Log message:
Update to 1.4.1. From the changelog:

API:

* Constructing a Query for a non-reference counted PostingSource object will
  now try to clone the PostingSource object (as happened in 1.3.4 and
  earlier).  This clone code was removed as part of the changes in 1.3.5 to
  support optional reference counting of PostingSource objects, but that breaks
  the case when the PostingSource object is on the stack and goes out of scope
  before the Query object is used.  Issue reported by Till Schäfer and analysed
  by Daniel Vrátil in a bug report against Akonadi:
  https://bugs.kde.org/show_bug.cgi?id=363741

* Add BM25PlusWeight class implementing the BM25+ weighting scheme, implemented
  by Vivek Pal (https://github.com/xapian/xapian/pull/104).

* Add PL2PlusWeight class implementing the PL2+ weighting scheme, implemented
  by Vivek Pal (https://github.com/xapian/xapian/pull/108).

* LMWeight: Implement Dir+ weighting scheme as DIRICHLET_PLUS_SMOOTHING.
  Patch from Vivek Pal.

* Add CoordWeight class implementing coordinate matching.  This can be useful
  for specialised uses - e.g. to implement sorting by the number of matching
  filters.

* DLHWeight,DPHWeight,PL2Weight: With these weighting schemes, the formulae
  can give a negative weight contribution for a term in extreme cases.  We
  used to try to handle this by calculating a per-term lower bound on the
  contribution and subtracting this from the contribution, but this idea
  is fundamentally flawed as the total offset it adds to a document depends on
  what combination of terms that document matches, meaning in general the
  offset isn't the same for every matching document.  So instead we now clamp
  each term's weight contribution to be >= 0.

* TfIdfWeight: Always scale term weight by wqf - this seems the logical
  approach as it matches the weighting we'd get if we weighted every non-unique
  term in the query, as well as being explicit in the Piv+ formula.

* Fix OP_SCALE_WEIGHT to work with all weighting schemes - previously it was
  ignored when using PL2Weight and LMWeight.

* PL2Weight: Greatly improve upper bound on weight:
  + Split the weight equation into two parts and maximise each separately as
    that gives an easily solvable problem, and in common cases the maximum is
    at the same value of wdfn for both parts.  In a simple test, the upper
    bounds are now just over double the highest weight actually achieved -
    previously they were several hundred times.  This approach was suggested by
    Aarsh Shah in: https://github.com/xapian/xapian/pull/48
  + Improve upper bound on normalised wdf (wdfn) - when wdf_upper_bound >
    doclength_lower_bound, we get a tighter bound by evaluating at
    wdf=wdf_upper_bound.  In a simple test, this reduces the upper bound on
    wdfn by 36-64%, and the upper bound on the weight by 9-33%.

* PL2Weight: Fix calculation of upper_bound when P2>0.  P2 is typically
  negative, but for a very common term it can be positive and then we should
  use wdfn_lower not wdfn_upper to adjust P_max.

* Weight::unserialise(): Check serialised form is empty when unserialising
  parameter-free schemes BoolWeight, DLHWeight and DPHWeight.

* TermGenerator::set_stopper_strategy(): New method to control how the Stopper
  object is used.  Patch from Arnav Jain.

* QueryParser: Fix handling of CJK query over multiple prefixes.  Previously
  all the n-gram terms were AND-ed together - now we AND together for each
  prefix, then OR the results.  Fixes #719, reported by Aaron Li.

* Add Database::get_revision() method which provides access to the database
  revision number for chert and glass, intended for use by xapiand.  Marked
  as experimental, so we don't have to go through the usual deprecation cycle
  if this proves not to be the approach we want to take.  Fixes #709,
  reported by German M. Bravo.

* Mark RangeProcessor constructor as `explicit`.

* Update to Unicode 9.0.0.

* Reimplement ESet and ESetIterator as we did for MSet and MSetIterator in
  1.3.5.  ESetIterator internally now counts down to the end of the ESet, so
  the end test is now against 0, rather than against eset.size().  And more of
  the trivial methods are now inlined, which reduces the number of relocations
  needed to load the library, and should give faster code which is a very
  similar size to before.

* MSetIterator and ESetIterator are now STL-compatible random_access_iterators
  (previously they were only bidirectional_iterators).

* TfIdfWeight: Support freq and squared IDF normalisations.  Patch from Vivek
  Pal.

* New Xapian::Query::OP_INVALID to provide an "invalid" query object.

* Reject OP_NEAR/OP_PHRASE with non-leaf subqueries early to avoid a
  potential segmentation fault if the non-leaf subquery decayed at
  just the wrong moment.  See #508.

* Reduce positional queries with a MatchAll or PostingSource subquery to
  MatchNothing (since these subqueries have no positional information, so
  the query can't match).

* Deprecate ValueRangeProcessor and introduce new RangeProcessor class as
  a replacement.  RangeProcessor()::operator()() method returns Xapian::Query,
  so a range can expand to any query.  OP_INVALID is used to signal that
  a range is not recognised.  Fixes #663.

* Combining of ranges over the same quantity with OP_OR is now handled by
  an explicit "grouping" parameter, with a sensible default which works
  for value range queries.  Boolean term prefixes and FieldProcessor now
  support "grouping" too, so ranges and other filters can now be grouped
  together.

* Formally deprecate WritableDatabase::flush().  The replacement commit()
  method was added in 1.1.0, so code can be switched to use this and still
  work with 1.2.x.

* Fix handling of a self-initialised PIMPL object (e.g. Xapian::Query q(q);).
  Previously the uninitialised pointer was copied to itself, resulting in
  undefined behaviour when the object was used to destroyed.  This isn't
  something you'd see in normal code, but it's a cheap check which can probably
  be optimised away by the compiler (GCC 6 does).

* The Snipper class has been replaced with a new MSet::snippet() method.
  The implementation has also been redone - the existing implementation was
  slower than ideal, and didn't directly consider the query so would sometimes
  selects a snippet which doesn't contain any of the query terms (which users
  quite reasonably found surprising).  The new implementation is faster, will
  always prefer snippets containing query terms, and also understands exact
  phrases and wildcards.  Fixes #211.

* Add optional reference counting support for ErrorHandler, ExpandDecider,
  KeyMaker, PostingSource, Stopper and TermGenerator.  Fixes #186, reported
  by Richard Boulton.  (ErrorHandler's reference counting isn't actually used
  anywhere in xapian-core currently, but means we can hook it up in 1.4.x if
  ticket #3 gets addressed).

* Deprecate public member variables of PostingSource.  The new getters and/or
  setters added in 1.2.23 and 1.3.5 are preferred.  Fixes #499, reported by
  Joost Cassee.

* Reimplement MSet and MSetIterator.  MSetIterator internally now counts down
  to the end of the MSet, so the end test is now against 0, rather than against
  mset.size().  And more of the trivial methods are now inlined, which reduces
  the number of relocations needed to load the library, and should give faster
  code which is a very similar size to before.

* Only issue prefetch hints for documents if MSet::fetch() is called.  It's not
  useful to send the prefetch hint right before the actual read, which was
  happening since the implementation of prefetch hints in 1.3.4.  Fixes #671,
  reported by Will Greenberg.

* Fix OP_ELITE_SET selection in multi-database case - we were selecting
  different sets for each subdatabase, but removing the special case check for
  termfreq_max == 0 solves that.

* Remove "experimental" marker from FieldProcessor, since we're happy \ 
with the
  API as-is.  Reported by David Bremner on xapian-discuss.

* Remove "experimental" marker from Database::check().  We've not had any
  negative feedback on the current API.

* Databse::check() now checks that doccount <= last_docid.

* Database::compact() on a WritableDatabase with uncommitted changes could
  produce a corrupted output.  We now throw Xapian::InvalidOperationError in
  this case, with a message suggesting you either commit() or open the database
  from disk to compact from.  Reported by Will Greenberg on #xapian-discuss

* Add Arabic stemmer.  Patch from Assem Chelli in
  https://github.com/xapian/xapian/pull/45

* Improve the Arabic stopword list.  Patch from Assem Chelli.

* Make functions defined in xapian/iterator.h 'inline'.

* Don't force the user to specify the metric in the geospatial API -
  GreatCircleMetric is probably what most users will want, so a sensible
  default.

* Xapian::DBCHECK_SHOW_BITMAP: This was added in 1.3.0 (so has never been in
  a stable release) and was superseded by Xapian::DBCHECK_SHOW_FREELIST in
  1.3.2, so just remove it.

* Make setting an ErrorHandler a no-op - this feature is deprecated and we're
  not aware of anyone using it.  We're hoping to rework ErrorHandler in 1.4.x,
  which will be simpler without having to support the current behaviour as well
  as the new.  See #3.

* Update to Unicode 8.0.0.  Fixes #680.

* Overhaul database compaction API.  Add a Xapian::Database::compact() method,
  with the Database object specifying the source database(s).
  Xapian::Compactor is now just a functor to use if you want to control
  progress reporting and/or the merging of user metadata.  The existing API
  has been reimplemented using the new one, but is marked as deprecated.

* Add support for a default value when sorting.  Fixes #452, patch from
  Richard Boulton.

* Make all functor objects non-copyable.  Previously some were, some weren't,
  but it's hard to correctly make use of this ability.  Fixes #681.

* Fix use after free with WILDCARD_LIMIT_MOST_FREQUENT.  If we tried to open a
  postlist after processing such a wildcard, the postlist hint could be
  pointing to a PostList object which had been deleted.  Fixes #696, reported
  by coventry.

* Add support for optional reference counting of MatchSpy objects.

* Improve Document::get_description() - the output is now always valid UTF-8,
  doesn't contain implementation details like "Document::Internal", \ 
and more
  clearly reports if the document is linked to a database.

* Remove XAPIAN_CONST_FUNCTION marker from sortable_serialise_() helper, as it
  writes to the passed in buffer, so it isn't const or pure.  Fixes
  decvalwtsource2 testcase failure when compiled with clang.

* Make PostingSource::set_maxweight() public - it's hard to wrap for the
  bindings as a protected method.  Fixes #498, reported by Richard Boulton.

* Database:

  + Add new flag Xapian::DB_RETRY_LOCK which allows opening a database for
    writing to wait until it can get a write lock.  (Fixes #275, reported by
    Richard Boulton).

  + Fix Database::get_doclength_lower_bound() over multiple databases when some
    are empty or consist only of zero-length documents.  Previously this would
    report a lower bound of zero, now it reports the same lowest bound as a
    single database containing all the same documents.

  + Database::check(): When checking a single table, handle the ".glass"
    extension on glass database tables, and use the extension to guide the
    decision of which backend the table is from.

* Query:

  + Add new OP_WILDCARD query operator, which expands wildcards lazily, so now
    we create the PostList tree for a wildcard directly, rather than creating
    an intermediate Query tree.  OP_WILDCARD offers a choice of ways to limit
    wildcard expansion (no limit, throw an exception, use the first N by term
    name, or use the most frequent N).  (See tickets #48 and #608).

* QueryParser:

  + Add new set_max_expansion() method which provides access to OP_WILDCARD's
    choice of ways to limit expansion and can set limits for partial terms as
    well as for wildcards.  Partial terms now default to the 100 most frequent
    matching terms.  (Completes #608, reported by boomboo).

  + Deprecate set_max_wildcard_expansion() in favour of set_max_expansion().

* Add support for optional reference counting of FieldProcessor and
  ValueRangeProcessor objects.

* Update Unicode character database to Unicode 7.0.0.

* New Xapian::Snipper class from Mihai Bivol's GSOC 2012 project.  (mostly
  fixes #211)

* Fix all get_description() methods to always return UTF-8 text.  (fixes #620)

* Database::check():

  + Alter to take its "out" parameter as a pointer to std::ostream \ 
instead of a
    reference, and make passing NULL mean "do not produce output", and make
    the second and third parameters optional, defaulting to a quiet check.

  + Escape invalid UTF-8 data in keys and tags reported by xapian-check, using
    the same code we use to clean up strings returned by get_description()
    methods.

  + Correct failure message which talks above the root block when it's actually
    testing a leaf key.

  + Rename DBCHECK_SHOW_BITMAP to DBCHECK_SHOW_FREELIST (old name still
    provided for now, but flagged as deprecated - DBCHECK_SHOW_BITMAP was new
    in 1.3.0, so will likely be removed before 1.4.0).

* Methods and functions which take a string to unserialise now consistently
  call that parameter "serialised".

* Weight: Make number of distinct terms indexing each document and the
  collection frequency of the term available to subclasses.  Patch from
  Gaurav Arora's Language Modelling branch.

* WritableDatabase: Add support for multiple subdatabases, and support opening
  a stub database containing multiple subdatabases as a WritableDatabase.

* WritableDatabase can now be constructed from just a pathname (defaulting to
  opening the database with DB_CREATE_OR_OPEN).

* WritableDatabase: Add flags which can be bitwise OR-ed into the second
  argument when constructing:

  + Xapian::DB_NO_SYNC: to disable use of fsync, etc

  + Xapian::DB_DANGEROUS: to enable in-place updates

  + Xapian::DB_BACKEND_CHERT: if creating, create a chert database

  + Xapian::DB_BACKEND_GLASS: if creating, create a glass database

  + Xapian::DB_NO_TERMLIST: create a database without a termlist (see #181)

  + Xapian::DB_FULL_SYNC flag - if this is set for a database, we use the Mac
    OS X F_FULL_SYNC instead of fdatasync()/fsync()/etc on the version file
    when committing.

* Database: Add optional flags argument to constructor - the following can be
  bitwise OR-ed into it:

  + Xapian::DB_BACKEND_CHERT (only open a chert database)

  + Xapian::DB_BACKEND_GLASS (only open a glass database)

  + Xapian::DB_BACKEND_STUB (only open a stub database)

* Xapian::Auto::open_stub() and Xapian::Chert::open() are now deprecated in
  favour of these new flags.

* Add LMWeight class, which implements the Unigram Language Modelling weighting
  scheme.  Patch from Gaurav Arora.

* Add implementations of a number of DfR weighting schemes (BB2, DLH, DPH,
  IfB2, IneB2, InL2, PL2).  Patches from Aarsh Shah.

* Add support for the Bo1 query expansion scheme.  Patch from Aarsh Shah.

* Add Enquire::set_time_limit() method which sets a timelimit after which
  check_at_least will be disabled.

* Database: Trying to perform operations on a database with no subdatabases now
  throws InvalidOperationError not DocNotFoundError.

* Query: Implement new OP_MAX query operator, which returns the maximum weight
  of any of its subqueries.  (see #360)

* Query: Add methods to allow introspection on Query objects - currently you
  can read the leaf type/operator, how many subqueries there are, and get a
  particular subquery.  For a query which is a term, Query::get_terms_begin()
  allows you to get the term.  (see #159)

* Query: Only simplify OP_SYNONYM with a single subquery if that subquery is a
  term or MatchAll.

* Avoid two vector copies when storing term positions in most common cases.

* Reimplement version functions to use a single function in libxapian which
  returns a pointer to a static const struct containing the version
  information, with inline wrappers in the API header which call this.  This
  means we only need one relocation instead of 4, reducing library load time a
  little.

* Make TermGenerator flags an anonymous enum, and typedef TermGenerator::flags
  to int for backward compatibility with existing user code which uses it.

* Stem: Fix incorrect Unicode codepoints for o-double-acute and u-double-acute
  in the Hungarian Snowball stemmer.  Reported by Tom Lane to snowball-discuss.

* Stem: Add an early english stemmer.

* Provide the stopword lists from Snowball plus an Arabic one, installed in
  ${prefix}/share/xapian-core/stopwords/.  Patch from Assem Chelli, fixes #269.

* Improve check for direct inclusion of Xapian subheaders in user code to
  catch more cases.

* Add simple API to help with creating language-idiomatic iterator wrappers
  in <xapian/iterator.h>.

* Give an compilation error if user code tries to include API headers other
  than xapian.h directly - these other headers are an internal implementation
  detail, but experience has shown that some people try to include them
  directly.  Please just use '#include <xapian.h>' instead.

* Update Unicode character database to Unicode 6.2.0.

* Add FieldProcessor class (ticket#128) - currently marked as an experimental
  API while we sort out how best to sort out exactly how it interacts with
  other QueryParser features.

* Add implementation of several TF-IDF weighting schemes via a new TfIdfWeight
  class.

* Add ExpandDeciderFilterPrefix class which only return terms with a particular
  prefix.  (fixes #467)

* QueryParser: Adjust handling of Unicode opening/closing double quotes - if a
  quoted boolean term was started with ASCII double quote, then only ASCII
  double quote can end it, as otherwise it's impossible to quote a term
  containing Unicode double quotes.

* Database::check(): If the database can't be opened, don't emit a bogus
  warning about there being too many documents to cross-check doclens.

* TradWeight,BM25Weight: Throw SerialisationError instead of NetworkError if
  unserialise() fails.

* QueryParser: Change the default stemming strategy to STEM_SOME, to eliminate
  the API gotcha that setting a stemmer is ignored until you also set a
  strategy.

* Deprecate Xapian::ErrorHandler.  (ticket#3)

* Stem: Generate a compact and efficient table to decode language names.  This
  is both faster and smaller than the approach we were using, with the added
  benefit that the table is auto-generated.

* xapian.h:

  + Add check for Qt headers being included before us and defining
    'slots' as a macro - if they are, give a clear error advising how to work
    around this (previously compilation would fail with a confusing error).

  + Add a similar check for Wt headers which also define 'slots' as a macro
    by default.

* Update Unicode character database to Unicode 6.1.0.  (ticket#497)

* TermIterator returned by Enquire::get_matching_terms_begin(),
  Query::get_terms_begin(), Database::synonyms_begin(),
  QueryParser::stoplist_begin(), and QueryParser::unstem_begin() now stores the
  list of terms to iterate much more compactly.

* QueryParser:

  + Allow Unicode curly double quote characters to start and/or end phrases.

  + The set_default_op() method will now reject operators which don't make
    sense to set.  The operators which are allowed are now explicitly
    documented in the API docs.

* Query: The internals have been completely reimplemented (ticket#280).  The
  notable changes are:

  + Query objects are smaller and should be faster.

  + More readable format for Query::get_description().

  + More compact serialisation format for Query objects.

  + Query operators are no longer flattened as you build up a tree (but the
    query optimiser still combines groups of the same operator).  This means
    that Query objects are truly immutable, and so we don't need to copy Query
    objects when composing them.  This should also fix a few O(n*n) cases when
    building up an n-way query pair-wise.  (ticket#273)

  + The Query optimiser can do a few extra optimisations.

* There's now explicit support for geospatial search (this API is currently
  marked as experimental).  (ticket#481)

* There's now an API (currently experimental) for checking the integrity of
  databases (partly addresses ticket#238).

* Database::reopen() now returns true if the database may have been reopened
  (previously it returned void).  (ticket#548)

* Deprecate Xapian::timeout in favour of POSIX type useconds_t.

* Deprecate Xapian::percent and use int instead in the API and our own code.

* Deprecate Xapian::weight typedef in favour of just using double and change
  all uses in the API and our own code.  (ticket#560)

* Rearrange members of Xapian::Error to reduce its size (from 48 to 40 bytes on
  x86-64 Linux).

* Assignment operators for PositionIterator and TermIterator now return *this
  rather than void.

* PositionIterator, PostingIterator, TermIterator and ValueIterator now
  handle their reference counts in hand-crafted code rather than using
  intrusive_ptr/RefCntPtr, which means the compiler can inline the destructor
  and default constructor, so a comparison to an end iterator should now
  optimise to a simple NULL pointer check, but without the issues which the
  ValueIteratorEnd_ proxy class approach had (such as not working in templates
  or some cases of overload resolution).

* Enquire:

  + Previously, Enquire::get_matching_terms_begin() threw InvalidArgumentError
    if the query was empty.  Now we just return an end iterator, which is more
    consistent with how empty queries behave elsewhere.

  + Remove the deprecated old-style match spy approach of using a MatchDecider.

* Remove deprecated Sorter class and MultiValueSorter subclass.

* Xapian::Stem:

  + Add stemmers for Armenian (hy), Basque (eu), and Catalan (ca).

  + Stem::operator= now returns a reference to the assigned-to object.

testsuite:

* OP_SCALE_WEIGHT: Check top weight is non-zero - if it is zero, tests which
  try to check that OP_SCALE_WEIGHT works will always pass.

* testsuite: Check SerialisationError descriptions from Xapian::Weight
  subclasses mention the weighting scheme name.

* Merge queryparsertest and termgentest into apitest.  Their testcases now use
  the backend manager machinery in the testharness, so we don't have to
  hard-code use of inmemory and chert backends, but instead run them under all
  backends which support the required features.  This fixes some test failures
  when both chert and glass are disabled due to trying to run spelling tests
  with the inmemory backend.

* Avoid overflowing collection frequency in totaldoclen1.  We're trying to test
  total document length doesn't wrap, so avoid collection freq overflowing in
  the process, as that triggers errors when running the testsuite under ubsan.
  We should handle collection frequency overflow better, but that's a separate
  issue.

* Add some test coverage for ESet::get_ebound().

* Fix testcase notermlist1 to check correct table extension - ".glass" not
  ".DB" (chert doesn't support DB_NO_TERMLIST).

* unittest: We can't use Assert() to unit test noexcept code as it throws an
  exception if it fails.  Instead set up macros to set a variable and return if
  an assertion fails in a unittest testcase, and check that variable in the
  harness.

* Add unit test for internal C_isupper(), etc functions.

* If command line option --verbose/-v isn't specified, set the verbosity level
  from environmental variable VERBOSE.

* Re-enable replicate3 for glass, as it no longer fails.

* Add more test coverage for get_unique_terms().

* Don't leave an extra fd open when starting xapian-tcpsrv for remotetcp tests.

* Extend checkstatsweight1 to check that Weight::get_collection_freq() returns
  the same number as Database::get_collection_freq().

* queryparsertest: Add testcase for FieldProcessor on boolean prefix with
  quoted contents.

* queryparsertest: Enable some disabled cases which actually work (in some
  cases with slightly tweaked expected answers which are equivalent to those
  that were shown).

* Make use of the new writable multidatabase feature to simplify the
  multi-database handling in the test harness.

* Change querypairwise1_helper to repeat the query build 100 times, as with a
  fast modern machine we were sometimes trying with so many subqueries that we
  would run out of stack.

* apitest: Use Xapian::Database::check() in cursordelbug1.  (partly addresses
  #238)

* apitest: Test Query ops with a single MatchAll subquery.

* apitest: New testcase readonlyparentdir1 to ensure that commit works with a
  read-only parent directory.

* tests/generate-api_generated: Test that the string returned by a
  get_description() method isn't empty.

* Use git commit hash in title of test coverage reports generated from a git
  tree.

* Make unittest use the test harness, so it gets all the valgrind and fd leak
  checks, and other handy features all the other tests have.

* Improve test coverage in several places.

* Compress generated HTML files in coverage report.

matcher:

* Fix stats passed to Weight with OP_SYNONYM.  Previously the number of
  unique terms was never calculated, and a term which matched all documents
  would be optimised to an all-docs postlist, which fails to supply the
  correct wdf info.

* Use floating point calculation for OR synonym freq estimates.  The division
  was being done as an integer division, which means the result was always
  getting rounded down rather than rounded to the nearest integer.

* Fix upper bound on matches for OP_XOR.  Due to a reversed conditional, the
  estimate could be one too low in some cases where the XOR matched all the
  documents in the database.

* Improve lower bound on matches for OP_XOR.  Previously the lower bound was
  always set to 0, which is valid, but we can often do better.

* Optimise value range which is a superset of the bounds.  If the value
  frequency is equal to the doccount, such a range is equivalent to MatchAll,
  and we now avoid having to read the valuestream at all.

* Optimise OP_VALUE_RANGE when the upper bound can't be exceeded.  In this
  case, we now use ValueGePostList instead of ValueRangePostList.

* Streamline collation of statistics for use by weighting schemes - tests show
  a 2% or so increase in speed in some cases.

* If a term matches all documents and its weight doesn't depend on its wdf, we
  can optimise it to MatchAll (the previous requirement that maxpart == 0 was
  unnecessarily strict).

* Fix the check for a term which matches all documents to use the sub-db
  termfreq, not the combined db termfreq.

* When we optimise a postlist for a term which matches all documents to use
  MatchAll, we still need to set a weight object on it to get percentages
  calculated correctly.

* Drop MatchNothing subqueries in OR-like situations in add_subquery() rather
  than adding them and then handling it later.

* Handle the left side of AND_NOT and AND_MAYBE being MatchNothing in
  add_subquery() rather than in done().

* Handle QueryAndLike with a MatchNothing subquery in add_subquery() rather
  than done().

* Query: Multi-way operators now store their subquery pointers in a custom
  class rather than std::vector<Xapian::Query>.  The custom class take the
  same amount of space, or often less.  It's particularly efficient when
  there are two subqueries, which is very desirable as we no longer flatten a
  subtree of the same operator as we build the query.

* Optimise an unweighted query term which matches all the documents in a
  subdatabase to use the "MatchAll" postlist.  (ticket#387)

glass backend:

* Fix allterms with prefix on glass with uncommitted changes.  Glass aims to
  flush just the relevant postlist changes in this case but the end of the
  range to flush was wrong, so we'd only actually flush changes for a term
  exactly matching the prefix.  Fixes #721.

* Fix Database::check() parsing of glass changes file header.  In practice this
  was unlikely to actually cause problems.

* Make glass the default backend.  The format should now be stable, except
  perhaps in the unlikely event that a bug emerges which requires a format
  change to address.

* Don't explicitly store the 2 byte "component_of" counter for the first
  component of every Btree entry in leaf blocks - instead use one of the upper
  bits of the length to store a "first component" flag.  This directly \ 
saves 2
  bytes per entry in the Btree, plus additional space due to fewer blocks and
  fewer levels being needed as a result.  This particularly helps the position
  table, which has a lot of entries, many of them very small.  The saving would
  be expected to be a little less than the saving from the change which shaved
  2 bytes of every Btree item in 1.3.4 (since that saved 2 bytes multiple times
  for large entries which get split into multiple items).  A simple test
  suggests a saving of several percent in total DB size, which fits that.  This
  change reduces the maximum component size to 8194, which affects tables
  with a 64KB blocksize in normal use and tables with >= 16KB blocksize with
  full compaction.

* Refactor glass backend key comparison - == and < operations are replaced by
  a compare() function returns negative, 0 or positive (like strcmp(), memcmp()
  and std::string::compare()).  This allows us to avoid a final compare to
  check for equality when binary chopping, and to terminate early if the binary
  chop hits the exact entry.

* If a cursor is moved to an entry which doesn't exist, we need to step back to
  the first component of previous entry before we can read its tag.  However we
  often don't actually read its tag (e.g. if we only wanted the key), so make
  this stepping back lazy so we can avoid doing it when we don't want to read
  the tag.

* Avoid creating std::string objects to hold data when compressing and
  decompressing tags with zlib.

* Store minimum compression length per table in the version file, with 0
  meaning "don't compress".  Currently you can only change this \ 
setting with a
  hex editor on the file, but now it is there we can later make use of it
  without needing a database format change.

* Database::check() now performs additional consistency checks for glass.
  Reported by Jean-Francois Dockes and Bob Cargill via xapian-discuss.

* Database::check(): check docids don't exceed db_last_docid when checking
  a single glass table.

* We now throw DatabaseCorruptError in a few cases where it's appropriate
  but we didn't previously, in particular in the case where all the files in a
  DB have been truncated to zero size (which makes handling of this case
  consistent with chert).

* Fix compaction to a single file which already exists.  This was hanging.
  Noted by Will Greenberg on #xapian.

* Shave 2 bytes of every Btree item (which will probably typically reduce
  database size by several percent).

* More compact item format for branch blocks - 2 bytes per item smaller.  This
  means each branch block can branch more ways, reducing the number of Btree
  levels needed, which is especially helpful for cold-cache search times.

* Track an upper bound on spelling word frequency.  This isn't currently used,
  but will be useful for improving the spelling algorithm, and we want to
  stabilise the glass backend format.  See #225, reported by Philip Neustrom.

* Support 64-bit docids in the glass backend on-disk format.  This changes the
  encoding used by pack_uint_preserving_sort() to one which supports 64 bit
  values, and is a byte smaller for values 16384-32767, and the same size for
  all other 32 bit values.  Fixes #686, from original report by James Aylett.

* Use memcpy() not memmove() when no risk of overlap.

* Store length of just the key data itself, allowing keys to be up to 255 bytes
  long - the previous limit was 252.

* Change glass to store DB stats in the version file.  Previously we stored
  them in a special item in the postlist table, but putting them in the version
  file reduces the number of block reads required to open the database, is
  simpler to deal with, and means we can potentially recalculate tight upper
  and lower bounds for an existing database without having to commit a new
  revision.

* Add support for a single-file variant for glass.  Currently such databases
  can only be opened for reading - to create one you need to use
  xapian-compact (or its API equivalent).  You can embed such databases within
  another file, and open them by passing in a file descriptor open on that file
  and positioned at the offset the database starts at).  Database::check() also
  supports them.  Fixes #666, reported by Will Greenberg (and previously
  suggested on xapian-discuss by Emmanuel Engelhart).

* Avoid potential DB corruption with full-compaction when using 64K blocks.

* Where posix_fadvise() is available, use it to prefetch postlist Btree blocks
  from the level below the root block which will be needed for postlists of
  terms in the query, and similarly for the docdata table when MSet::fetch() is
  called.  Based on patch by Will Greenberg in #671.

* When reporting freelist errors during a database check, distinguish between a
  block in use and in the freelist, and a block in the freelist more than once.

* Fix compaction and database checking for the change to the format of keys
  in the positionlist table which happened in 1.3.2.

* After splitting a block, we always insert the new block in the parent right
  after the block it was split from - there's no need to binary chop.

* Avoid infinite recursion when we hit the end of the freelist block we're
  reading and the end of the block we're writing at the same time.

* Fix freelist handling to allow for the newly loaded first block of the
  freelist being already used up.

* 'brass' backend renamed to 'glass' - we decided to use names in ascending
  alphabetical order to make it easier to understand which backend is newest,
  and since 'flint' was used recently, we skipped over 'd', 'e' and 'f'.

* Change positionlist keys to be ordered by term first rather than docid first,
  which helps phrase searching significantly.  For more efficient indexing,
  positionlist changes are now batched up in memory and written out in key
  order.

* Use a separate cursor for each position list - now we're ordering the
  position B-tree by term first, phrase matching would cause a single cursor
  to cycle between disparate areas of the B-tree and reread the same blocks
  repeatedly.

* Reference count blocks in the btree cursor, so cursors can cheaply share
  blocks.  This can significantly reduce the amount of memory used by cursors
  for queries which contain a lot of terms (e.g. wildcards which expand to a
  lot of terms).

* Under glass, optimise the turning of a query into a postlist to reuse the
  cursor blocks which are the same as the previous term's postlist.  This is
  particularly effective for a wildcard query which expands to a lot of terms.

* Keep track of unused blocks in the Btrees using freelists rather than
  bitmaps.  (fixes #40)

* Eliminate the base files, and instead store the root block and freelist
  pointers in the "iamglass" file.

* When compacting, sync all the tables together at the end.

* In DB_DANGEROUS mode, update the version file in-place.

* Only actually store the document data if it is non-empty.  The table which
  holds the document data is now lazily created, so won't exist if you never
  set the document data.

* Iterating positional data now decodes it lazily, which should speed up
  phrases which include common words.

* Compress changesets in brass replication. Increments the changeset version.
  Ticket #348

* Restore two missing lines in database checking where we report a block with
  the wrong level.

* When checking if a block was newly allocated in this revision, just look
  at its revision number rather than consulting the base file's bitmap.

remote backend:

* Improve handling of invalid remote stub entries: Entries without a colon now
  give an error rather than being quietly skipped; IPv6 isn't yet supported,
  but entries with IPv6 addresses now result in saner errors (previously the
  colons confused the code which looks for a port number).

* Fix hook for remote support of user weighting schemes.  The commented-out
  code used entirely the wrong class - now we use the server object we have
  access to, and forward the method to the class which needs it.

* Avoid dividing zero by zero when calculating the average length for an empty
  database.

* Bump remote protocol version to 38.0, due to extra statistics being tracked
  for weighting.

* Make Weight::Internal track if any max_part values are set, so we don't need
  to serialise them when they've not been set.

* Prefix compress list of terms and metadata keys in the remote protocol.
  This requires a remote protocol major version bump.

* When propagating exceptions from a remote backend server, the protocol now
  sends a numeric code to represent which exception is being propagated, rather
  than the name of the type, as a number can be turned back into an exception
  with a simple switch statement and is also less data to transfer.
  (ticket#471)

* Remote protocol (these changes require a protocol major version bump):

  + Unify REPLY_GREETING and REPLY_UPDATE.

  + Send (last_docid - doccount) instead of last_docid and (doclen_ubound -
    doclen_lbound) instead of doclen_ubound.

* Remove special check which gives a more helpful error message when a modern
  client is used against a remote server running Xapian <= 0.9.6.

chert backend:

* When using 64-bit Xapian::docid, consistently use the actual maximum valid
  docid value rather instead of the maximum value the type can hold.

* Where posix_fadvise() is available, use it to prefetch postlist Btree blocks
  from the level below the root block which will be needed for postlists of
  terms in the query, and similarly for the record table when MSet::fetch() is
  called.  Based on patch by Will Greenberg in #671.

* Fix problems with get_unique_terms() on a modified chert database.

* Fix xapian-check on a single chert table, which seg faulted in 1.3.2.

* Improve DBCHECK_FIX:

  + if fixing a whole database, we now take the revision from the first table
    we successfully look at, which should be correct in most cases, and is
    definitely better than trying to determine the revision of each broken
    table independently.

  + handle a zero-sized .DB file.

  + After we successfully regenerate baseA, remove any empty baseB file to
    prevent it causing problems.  Tracked down with help from Phil Hands.

* Iterating positional data now decodes it lazily, which should speed up
  phrases which include common words.

flint backend:

* Remove flint backend.

Log message:
Update to 1.2.23. From the changelog:

API:

* PostingSource: Public member variables are now wrapped by methods (mostly
  getters and/or setters, depending on whether they should be readable,
  writable or both).  In 1.3.5, the public members variables have been
  deprecated - we've added the replacement methods in 1.2.23 as well to make
  it easier for people to migrate over.

chert backend:

* xapian-check now performs additional consistency checks for chert. Reported
  by Jean-Francois Dockes and Bob Cargill via xapian-discuss.

documentation:

* Update links to Xapian website and trac to use https, which is now supported,
  thanks to James Aylett.

portability:

* On older Linux kernels, rename() of a file within a directory on NFS can
  sometimes erroneously fail with EXDEV.  This should only happen if you
  try to rename a file across filing systems, so workaround this issue by
  retrying up to 5 times on EXDEV (which should be plenty to avoid this
  bug, and we don't want to risk looping forever).  Fixes #698, reported by
  Mark Dufour.

Log message:
Update to 1.2.22. From the changelog:

API:

* Add FLAG_CJK_NGRAM for QueryParser and TermGenerator.  Has the same effect as
  setting the environment variable XAPIAN_CJK_NGRAM.  Fixes #180, reported by
  Richard Boulton, with contributions from Pavel Strashkin, Mikkel Kamstrup
  Erlandsen and Brandon Schaefer.

* Fix bug parsing multiple non-exclusive filter terms - previously this could
  result in such filters effectively being ignored.

* Fix Database::get_doclength_lower_bound() over multiple databases when some
  are empty or consist only of zero-length documents.  Previously this would
  report a lower bound of zero, now it reports the same lowest bound as a
  single database containing all the same documents.

* Make Database::get_wdf_upper_bound("") return 0.

* Mark constructors taking a single argument as "explicit" to avoid \ 
unwanted
  implicit conversions.

testsuite:

* If command line option --verbose/-v isn't specified, set the verbosity level
  from environmental variable VERBOSE.

* Skip timed tests if $AUTOMATED_TESTING is set.  Fixes #553, reported by
  Dagobert Michelsen.

* Don't leave an extra fd open when starting xapian-tcpsrv for remotetcp tests.

* apitest: Revert disabling of part of adddoc5 for clang - the test failure was
  in fact due to a bug in 1.3.x, and 1.2.x was never affected.

* apitest: Tweak bounds checks in dbstats1 testcase - multi backends should
  give tight bounds.

brass backend:

* Format limit on docid now correctly imposed when sizeof(int) > 4.

* Avoid potential DB corruption with full-compaction when using 64K blocks.

chert backend:

* Format limit on docid now correctly imposed when sizeof(int) > 4.

* Avoid potential DB corruption with full-compaction when using 64K blocks.

flint backend:

* Format limit on docid now correctly imposed when sizeof(int) > 4.

* Avoid potential DB corruption with full-compaction when using 64K blocks.

remote backend:

* Fix to handle total document length exceeding 34,359,738,368.  (Fixes #678,
  reported by matf).

* Avoid dividing by zero when getting the average length for an empty database.

* Stop apparent error from remote server when read-only client disconnects.  A
  read-only client just closes the connection when done, but the server
  previously reported "Got exception NetworkError: Received EOF", \ 
which sounds
  like there was a problem.  Now we just say "Connection closed" here, and
  "Connection closed unexpectedly" if the client connects in the \ 
middle of an
  exchange.  Possibly fixes #654, reported by German M. Bravo.

* Give a clearer error message when the client and server remote protocol
  versions aren't compatible.

* Check length of key in MSG_SETMETADATA.

build system:

* pkg-config: Fix library name in .pc file to say "xapian" not \ 
"xapian-core".
  Reported by Eric Lindblad to the xapian-devel list.

* Private symbol decode_length() is no longer visible outside the library.

documentation:

* Stop maintaining ChangeLog files.  They make merging patches harder, and stop
  'git cherry-pick' from working as it should.  The git repo history should be
  sufficient for complying with GPLv2 2(a).

* Strip out "quickstart" examples which are out of date and rather \ 
redundant
  with the "simple" examples.

* Correct documentation of Enquire::get_query().  If no query has been set,
  the documentation said Xapian::InvalidArgumentError was thrown, but in
  fact we just return a default initialised Query object (i.e. Query()).  This
  seems reasonable behaviour and has been the case since Xapian 0.9.0.

* Document xapian-compact --blocksize takes an argument.

* Update snowball website link to snowballstem.org.

tools:

* xapian-replicate: Fix replication for files > 4GB on 32-bit platforms.
  Previously replication would fail to copy a file whose size didn't fit in
  size_t.  Fixes #685, reported by Josh Elsasser.

* xapian-tcpsrv: Better error if -p/--port not specified

* quest: Support `-f cjk_ngram`.

examples:

* xapian-metadata: Extend "list" subcommand to take optional key prefix.

portability:

* Fix new warnings from recent versions of GCC and clang.

* Add spaces between literal strings and macros which expand to literal strings
  for C++11 compatibility in __WIN32__-specific code.

* Need <unistd.h> for unlink() on FreeBSD, reported by Germán M. Bravo via
  github PR 72.

* Fix testsuite to build when S_ISSOCK() isn't defined.

* Don't provide our own implementation of sleep() under __WIN32__ if there
  already is one - mingw provides one, and in some situations it seems to clash
  with ours.  Reported to xapian-discuss by John Alveris.

* Add missing '#include <arpa/inet.h>' to htons().  Seems to be implicitly
  included on most platforms, but Interix needs it.  Reported by Eric Lindblad
  on xapian-discuss.

* Disable "<FUNCTION> is expected to return a value" warning \ 
from Sun's C++
  compiler, as it fires for functions ending in a "throw" statement.  \ 
Genuine
  instances will be caught by compilers with superior warning machinery.

* Prefer scalbn() to ldexp() where possible, since the former doesn't ever set
  errno.

* '#include <config.h>' in the "simple" examples, as when \ 
compiling with xlC on
  AIX, _LARGE_FILES gets defined by AC_SYS_LARGEFILE to enable large file
  support, and defining this changes the ABI of std::string, so it also needs
  to be defined when compiling code using Xapian.

* On cygwin, include <arpa/inet.h> instead of winsock headers for htons() and
  htonl().

* Include <cygwin/version.h> for CYGWIN_VERSION_API_MAJOR.

* Avoid referencing static members via an object in that object's own
  definition, as this doesn't work with all compilers (noted with GCC 3.3), and
  is a bit of an odd construct anyway.  Reported by Eric Lindblad on
  xapian-discuss.

* GCC < 3.4.2 lacks operator<< overloads for unsigned long long on some
  platforms, so simply work around this by using str(), as this isn't
  performance sensitive code.  Reported by Eric Lindblad on xapian-discuss.

* Fix delete which should be delete[] in brass backend cursor code.

Log message:
Add SHA512 digests for distfiles for textproc category

Problems found locating distfiles:
	Package cabocha: missing distfile cabocha-0.68.tar.bz2
	Package convertlit: missing distfile clit18src.zip
	Package php-enchant: missing distfile php-enchant/enchant-1.1.0.tgz

Otherwise, existing SHA1 digests verified and found to be the same on
the machine holding the existing distfiles (morden).  All existing
SHA1 digests retained for now as an audit trail.

Log message:
Added patch to fix compilation error (on -current, at least)

Log message:
Update to 1.2.21:

API:

* QueryParser: Extend the set of characters allowed in the start of a range to
  be anything except for '(' and characters <= ' '.  This better matches what's
  accepted for a range end (anything except for ')' and characters <= ' ').
  Reported by Jani Nikula.

matcher:

* Reimplement OP_PHRASE for non-exact phrases.  The previous implementation was
  buggy, giving both false positives and false negatives in rare cases when
  three or more terms were involved.  Fixes #653, reported by Jean-Francois
  Dockes.

* Reimplement OP_NEAR - the new implementation consistently requires the terms
  to occur at different positions, and fixes some previously missed matches.

* Fix a reversed check for picking the shorter position list for an exact
  phrase of two terms.  The difference this makes isn't dramatic, but can be
  measured (at least with cachegrind).  Thanks to kbwt for spotting this.

* When matching an exact phrase, if a term doesn't occur where we want, use
  its actual position to advance the anchor term, rather than just checking
  the next position of the anchor term.

brass backend:

* Fix cursor versioning to consider cancel() and reopen() as events where
  the cursor version may need incrementing, and flag the current cursor version
  as used when a cursor is rebuilt.  Fixes #675, reported by Germán M. Bravo.

* Avoid using file descriptions < 3 for writable database tables, as it risks
  corruption if some code in the same process tries to write to stdout or
  stderr without realising it is closed.  (Partly addresses #651)

chert backend:

* Fix cursor versioning to consider cancel() and reopen() as events where
  the cursor version may need incrementing, and flag the current cursor version
  as used when a cursor is rebuilt.  Fixes #675, reported by Germán M. Bravo.

* Avoid using file descriptions < 3 for writable database tables, as it risks
  corruption if some code in the same process tries to write to stdout or
  stderr without realising it is closed.  (Partly addresses #651)

* After splitting a block, we always insert the new block in the parent right
  after the block it was split from - there's no need to binary chop.

flint backend:

* Fix cursor versioning to consider cancel() and reopen() as events where
  the cursor version may need incrementing, and flag the current cursor version
  as used when a cursor is rebuilt.  Fixes #675, reported by Germán M. Bravo.

remote backend:

* Fix sort by value when multiple databases are in use and one or more are
  remote.  This change necessitated a minor version bump in the remote
  protocol.  Fixes #674, reported by Dylan Griffith.  If you are upgrading a
  live system which uses the remote backend, upgrade the servers before the
  clients.

build system:

* The compiler ABI check in the public API headers now issues a warning
  (instead of an error) for an ABI mismatch for ABI versions 2 and later
  (which means GCC >= 3.4).  The changes in these ABI versions are bug fixes
  for corner cases, so there's a good chance of things working - e.g. building
  xapian-bindings with GCC 5.1 (which defaults to ABI version 8) against
  xapian-core built with GCC 4.9 (which defaults to ABI version 2) seems to
  work OK.  A warning is still useful as a clue to what is going on if linking
  fails due to a missing symbol.

* xapian-config,xapian-core.pc: When compiling with xlC on AIX, the reported
  --cxxflags/--cflags now include -D_LARGE_FILES=1 as this is defined for the
  library, and defining it changes the ABI of std::string with this compiler,
  so it must also be defined when building code using the Xapian API.

* xapian-core.pc: Include --enable-runtime-pseudo-reloc in --libs output for
  mingw and cygwin, like xapian-config does.

* xapian-core.pc: Fix include directory reported by `pkg-config --cflags`.
  This bug was harmless if xapian-core was installed to a directory which was
  on the default header search path (such as /usr/include).

* xapian-config: Fix typo so cached result of test in is_uninstalled() is
  actually used on subsequent calls.  Fixes #676, reported (with patch) by Ryan
  Schmidt.

* configure: Changes in 1.2.19 broke the custom macro we use to probe for
  supported compiler flags such that the flags never got used.  This release
  fixes this problem.

* configure: Set default value for AUTOM4TE before AC_OUTPUT so the default
  will actually get used.  Only relevant when building in maintainer mode
  (e.g. from git).

* soaktest: Link with libtool's '-no-install' or '-no-fast-install', like we
  already do for other test programs, which means that libtool doesn't need to
  generate shell script wrappers for them on most platforms.

* Generate and install a file for pkg-config.  (Fixes#540)

* configure: Update link to cygwin FAQ in error message.

documentation:

* API documentation: Minor wording tweaks and formatting improvements.

* docs/deprecation.rst: Add deprecation of omindex --preserve-nonduplicates
  which happened in 1.2.4.

* HACKING: Update URL.

* HACKING: libtool 2.4.6 is now used for bootstrapping snapshots and releases.

* include/xapian/weight.h: Document the enum stat_flags values.

* docs/postingsource.rst: Use a modern class in postingsource example.  (Noted
  by James Aylett)

* docs/deprecation.rst,docs/replication.rst: Fix typos.

* Update doxygen configuration files to avoid warnings about obsolete tags from
  newer doxygen versions.

* HACKING: Update details of building Xapian packages.

tools:

* xapian-compact: Make sure we open all the tables of input databases at the
  same revision.  (Fixes #649)

* xapian-metadata: Add 'list' subcommand to list all the metadata keys.

* xapian-replicate: Fix connection timeout to be 10 seconds rather than 10000
  seconds (the incorrect timeout has been the case since 1.2.3).

* xapian-replicate: Set SO_KEEPALIVE for xapian-replicate's connection to the
  master, and add command line option to allow setting socket-level timeouts
  (SO_RCVTIMEO and SO_SNDTIMEO) on platforms that support them.  Fixes #546,
  reported by nkvoll.

* xapian-replicate-server: Avoid potentially reading uninitialised data if a
  changeset file is truncated.

* xapian-check: For chert and brass, cross-check the position and postlist
  tables to detect positional data for non-existent documents.

portability:

* Add spaces between literal strings and macros which expand to literal strings
  for C++11 compatibility.

* ValueCountMatchSpy::top_values_begin(): Fix the comparison function not to
  return true for two equal elements, which manifests as incorrect sorting in
  some cases when using clang's libc++ (which recent OS X versions do).

* apitest: The adddoc5 testcase fails under clang due to an exception handling
  bug, so just #ifdef out the problematic part of the testcase when building
  with clang for now.

* Fix clang warnings on OS X.  Reported by Germán M. Bravo.

* Fix examples to build with IBM's xlC compiler on AIX - they were failing due
  to _LARGE_FILES being defined for the library build but not for the examples,
  and defining this changes the ABI of std::string with this compiler.

* configure: Improve the probe for whether the test harness can use RTTI to
  work for IBM's xlC compiler (which defaults to not generating RTTI).

* Fix to build with Sun's C++ compiler.

* Use F_DUPFD where available to dup to a file descriptor which is >= 2, rather
  than calling dup() until we get one.

* When unserialising a double, avoid reading one byte past the end of the
  serialised value.  In practice this was harmless on most platforms, as
  dbl_max_mantissa is 255 for IEEE-754 format doubles, and at least GCC's
  std::string keeps the buffer nul-terminated.  Reported by Germán M. Bravo in
  github PR#67.

* When unserialising a double, add missing cast to unsigned char when we check
  if the value will fit in the double type.  On machines with IEEE-754 doubles
  (which is most current platforms) this happened to work OK before.  It would
  also have been fine on machines where char is unsigned by default.

* Fix incorrect use of "delete" which should be "delete []". \ 
 This is
  undefined behaviour in C++, though the type is POD, so in practice this
  probably worked OK on many platforms.

* When locking a database for writing, use F_OFD_SETLK where available, which
  avoids having to fork() a child process to hold the lock.  This currently
  requires Linux kernel >= 3.15, but it has been submitted to POSIX so
  hopefully will be widely supported eventually.  Thanks to Austin Clements for
  pointing out this now exists.

* Fix detection of fdatasync(), which appears to have been broken practically
  forever - this means we've probably been using fsync() instead, which
  probably isn't a big additional overhead.  Thanks to Vlad Shablinsky for
  helping with Mac OS X portability of this fix.

* configure: Define MINGW_HAS_SECURE_API under mingw to get _putenv_s()
  declared in stdlib.h.

* Use POSIX O_NONBLOCK in preference to O_NDELAY - the semantics of the latter
  differ between BSD and System V.

* According to POSIX, strerror() may not be thread safe, so use alternative
  thread-safe ways to translate errno values where possible.

* On Microsoft Windows, avoid defining EADDRINUSE, etc if they're already
  defined, and use WSAE* constants un-negated - they start from a high value
  so won't collide with E* constants.

debug code:

* Fix some overly strict assertions in flint, which caused apitest's
  cursordelbug1 to fail with assertions on.

* Add more assertions to the chert backend code.

Log message:
Update to 1.2.19. From the changelog:

API:

* Xapian::BM5Weight:

  + Improve BM25 upper bound in the case when our wdf upper bound > our
    document length lower bound.  Thanks to Craig Macdonald for pointing out
    this trick.

  + Pre-multiply termweight by (param_k1 + 1) rather than doing it for
    every weighted term in every document considered.

testsuite:

* Don't report apparent leaks of fds opened on /dev/urandom - at least on
  Linux, something in the C library seems to lazily open it, and the report of
  a possible leak followed by assurance that it's OK really is just noise we
  can do without.

matcher:

* Fix false matches reported for non-exact phrases in some cases.  Fixes the
  reduced testcase in #657, reported by Jean-Francois Dockes.

brass backend:

* Only full sync after writing the final base file (only affects Max OS X).

chert backend:

* Only full sync after writing the final base file (only affects Max OS X).

flint backend:

* Only full sync after writing the final base file (only affects Max OS X).

build system:

* For Sun's C++ compiler, pass -library=Crun separately since libtool looks for
  " -library=stlport4 " (with the spaces).  (fixes#650)

* Remove .replicatmp (created by the test suite) upon "make clean".

documentation:

* include/xapian/compactor.h: Fix formatting of doxygen comment.

* HACKING: freecode no longer accepts updates, so drop that item from the
  release checklist.

* docs/overview.rst: Add missing database path to example of using
  xapian-progsrv in a stub database file.

portability:

* Suppress unused typedef warnings from debugging logging macros, which occur
  in functions which always exit via throwing an exception when compiling with
  recent versions of GCC or clang.

* Fix debug logging code to compile with clang.  (fixes #657, reported by
  Germán M. Bravo)

debug code:

* Add missing RETURN() markup for debug logging in a few places, highlighted by
  warnings from recent GCC.

* Fix incorrect return types in debug logging annotations so that code compiles
  when configured with --enable-log.

Log message:
Update to 1.2.18. From the changelog:

API:

* Document: Fix get_docid() to return the docid for the sub-database (as it
  is explicitly documented to) for Document objects passed to functors like
  KeyMaker during the match.  (fixes#636, reported by Jeff Rand).

* Document: Don't store the termname in OmDocumentTerm - we were only using it
  in get_description() output and an exception message.  Speeds up indexing
  etext.txt using simpleindex by 0.4%, and should reduce memory usage a bit
  too.  (Change inspired by comments from Vishesh Handa on xapian-devel).

* Database: Iterating the values in a particular slot is now a bit more
  efficient for inmemory and remote backends (but still slow compared to
  flint, chert and brass).

testsuite:

* apitest: Expand crashrecovery1 to check that the expected base files exist
  and ones which shouldn't exist don't.

* queryparsertest: Fix testcase for empty wildcard followed by negation to
  enable FLAG_LOVEHATE so the negation is actually parsed.  Fortunately the
  fixed testcase passes.

matcher:

* OP_SYNONYM: avoid fetching the doclength if the weighting scheme doesn't
  need it and the calculated wdf for the synonym is <= doclength_lower_bound
  for the current subdatabase.  (fixes #360)

build system:

* Releases are now bootstrapped with libtool 2.4.2 instead of 2.4, and with
  config.guess and config.sub updated to the latest versions.

documentation:

* Add an example of initializing SimpleStopper using a file listing stopwords.
  (Patch from Assem Chelli)

* Improve the descriptions of the stem_strategy values in the API docs.
  (Reported by "oilap" on #xapian)

* docs/sorting.rst: Fix incorrect parameter types in Xapian::Weight
  subclass example.

* docs/glossary.rst: Add definition of "collection frequency".

* HACKING:

  + makeindex is now in Debian package texlive-binaries.

  + Replace a link to the outdated autotools "goat book" with a link to the
    "Portable Shell" chapter of the autoconf manual.

* include/xapian/base.h: Remove very out of date comments talking about atomic
  assignment and locking - since 0.5.0 we've adopted a "user locks" policy.
  (Reported by Jean-Francois Dockes)

examples:

* delve:

  + Add -A <prefix> option to list all terms with a particular prefix.

  + Send errors to stderr not stdout.

  + If -v is specified more than once, show even more info in some cases.
    (NEWS file claimed this was backported in 1.2.15, but it actually wasn't).

* quest:

  + Add --default-op option.

  + Add --weight option to allow the weighting scheme to be specified.

portability:

* Explicitly '#include <algorithm>' for std::max(), fixing build with VS2013.
  (Fixes#641, reported by "boomboo").

* Fix testcase blocksize1 not to try to delete an open database, which isn't
  possible under Windows.  (Fixes #643, reported by Chris Olds)

* docs/quickstart.rst: Split --cxxflags and --libs for portability (noted by
  "Hurricane Tong" on xapian-devel).

* Fix warnings with clang 5.0.

debug code:

* Add assertions that weighting scheme upper bounds aren't exceeded.

Log message:
Update to 1.2.17. From the changelog:

API:
* Enquire::set_sort_by_relevance_then_value() and
  Enquire::set_sort_by_relevance_then_key(): Fix sense of reverse parameter.
  Reported by "boomboo" on IRC.
* BM25Weight: Fix case where (k1 == 0 || b == 0) but k2 != 0.  Reported by
  "boomboo" on IRC.
* Unicode::tolower(): Fix to give correct results for U+01C5, U+01C8, U+01CB,
  and U+01F2 (previously these were left unchanged).
* PositionIterator,PostingIterator,TermIterator,ValueIterator: Don't segfault
  if skip_to() or check() is called on an iterator which is already at_end().
  Reported by David Bremner.
* ValueCountMatchSpy: get_description() on a default-constructed
  ValueCountMatchSpy object no longer fails when xapian-core is built with
  --enable-log.
* ValueCountMatchSpy: get_total() on a default-constructed ValueCountMatchSpy
  object now returns 0 rather than segfaulting.

testsuite:
* Automatically probe for and hook in eatmydata to the testsuite using the
  wrapper script it now includes.
* Fix apitest to build when brass, chert or flint are disabled.
* If -v/--verbose is specified more than once to a test program, show the
  diagnostic output for passing tests as well as failing/skipped ones.
* queryparsertest: Change qp_scale1 to time 5 repetitions of the large query to
  help average out variations.
* queryparsertest: Add test coverage for explicit synonym of a term with a
  prefix (e.g. ~foo:search).
* apitest: Remove code from registry* testcases which tries to test the
  consequences of throwing an exception from a destructor - it's complex to
  ensure we don't leak memory while doing this (it seems GCC doesn't release
  the object in this case, but clang does), and it's generally frowned upon,
  plus C++11 makes destructors noexcept by default.
* Fix "make check" to actually removed cached databases first, as is
  intended.

brass backend:
* Fix handling of invalid block sizes passed to Xapian::Brass::open() - the
  size gets fixed as documented, but the uncorrected size was passed to the
  base file (and abort() was called if 0 was passed).
* Validate "dir_end" when reading a block.  (fixes #592)
* When moving a cursor on a read-only table, check if the block we want is in
  the internal cursor.  We already do this for a writable table, as it is
  necessary for correctness, but it's a cheap check and may avoid asking the
  OS for a block we actually already have.
* Correctly report the database as closed rather than 'Bad file descriptor'
  in certain cases.
* Reuse a cursor for reading values from valuestreams rather than creating
  a new one each time.  This can dramatically reduce the number of blocks
  redundantly reread when sorting by value.  The rereads will generally get
  served from VM cache, but there's still an overhead to that.

chert backend:
* Fix handling of invalid block sizes passed to Xapian::Chert::open() - the
  size gets fixed as documented, but the uncorrected size was passed to the
  base file (and abort() was called if 0 was passed).
* Validate "dir_end" when reading a block.  (fixes #592)
* When moving a cursor on a read-only table, check if the block we want is in
  the internal cursor.  We already do this for a writable table, as it is
  necessary for correctness, but it's a cheap check and may avoid asking the
  OS for a block we actually already have.
* Correctly report the database as closed rather than 'Bad file descriptor'
  in certain cases.
* Reuse a cursor for reading values from valuestreams rather than creating
  a new one each time.  This can dramatically reduce the number of blocks
  redundantly reread when sorting by value.  The rereads will generally get
  served from VM cache, but there's still an overhead to that.

flint backend:
* Fix handling of invalid block sizes passed to Xapian::Flint::open() - the
  size gets fixed as documented, but the uncorrected size was passed to the
  base file (and abort() was called if 0 was passed).
* Validate "dir_end" when reading a block.  (fixes #592)
* When moving a cursor on a read-only table, check if the block we want is in
  the internal cursor.  We already do this for a writable table, as it is
  necessary for correctness, but it's a cheap check and may avoid asking the
  OS for a block we actually already have.
* Correctly report the database as closed rather than 'Bad file descriptor'
  in certain cases.

build system:
* configure: Improve reporting of GCC version.
* Use -no-fast-install on platforms where -no-install causes libtool to emit a
  warning.
* docs/Makefile.am: Fix handling of MAINTAINER_NO_DOCS.
* Include UnicodeData.txt and the script to generate the unicode tables from
  it.
* Compress source tarballs with xz instead of gzip.
* Split XAPIAN_LIBS out of XAPIAN_LDFLAGS so that -l flags for libraries
  configure detects are needed appear after -L flags specified by the user
  that may be needed to find such libraries.  (fixes#626)
* XO_LIB_XAPIAN now handles the user specifying a relative path in
  XAPIAN_CONFIG, e.g.: "./configure \ 
XAPIAN_CONFIG=../xapian-core/xapian-config"
* Adjust XO_LIB_XAPIAN to strip _gitNNN suffix from snapshot versions.
* configure: Handle git snapshot naming when calculating REVISION.
* configure: Enable -fshow-column for GCC - things like vim's quickfix mode
  will then jump to the appropriate column for a compiler error or warning, not
  just the appropriate line.
* configure: Report GCC version in configure output.

documentation:
* postingsource.rst: Clarify a couple of points (reported by "vHanda" \ 
on IRC).
* The API documentation shipped with the release is now generated with
  doxygen 1.8.5 instead of 1.5.9, which is most evident in the different
  HTML styling newer doxygen uses.
* Document how Utf8Iterator handles invalid UTF-8 in API documentation.
* Improve how descriptions of deprecated features appear in the API
  documentation.
* docs/remote_protocol.rst: Correct error in documentation of REPLY_DOCDATA
  message.
* docs/overview.rst: Correct documentation for how to specify "prog" remote
  databases in stub files.
* Direct users to git in preference to SVN - we'll be switching entirely in
  the near future.

portability:
* Protect the ValueIterator::check() method against Mac OS X SDK headers
  which define a check() macro.
* Fix warning from xlC compiler.
* Avoid use of grep -e in configure, as /usr/bin/grep on Solaris doesn't
  support -e.
* Fix check for flags which might be needed for ANSI mode for compilers called
  'cxx'.
* configure: Improve handling of Sun's C++ compiler - trick libtool into not
  adding -library=Cstd, and prefer -library=stdcxx4 if supported.  Explicitly
  add -library=Crun which seems to be required, even though the documentation
  suggests otherwise.
* configure: clang doesn't support -Wstrict-null-sentinel or -Wlogical-op, so
  don't pass it these options.
* Fix build errors and warnings with mingw.
* Suppress "unused local typedef" warnings from GCC 4.8.
* If the compiler supports C++11, use static_assert to implement
  CompileTimeAssert.
* tests/zlib-vg.c: Fix two warnings when compiled with clang.
* Fix failure when built with -D_GLIBCXX_DEBUG - we were modifying the top()
  element of a heap before calling pop(), such that the heap comparison
  operation (which is called when -D_GLIBCXX_DEBUG is on to verify the heap is
  valid) would read off the end of the data.  In a normal build, this issue
  would likely never manifest.
* configure: When generating ABI compatibility checks in xapian/version.h, pass
  $CXXFLAGS and $CPPFLAGS to $CXXCPP as they could contain options which affect
  the ABI (such as -fabi-version for GCC).  (Fixes #622)
* Microsoft GUIDs in binary form have reversed byte order in the first three
  components compared to standard UUIDs, so the same database would report a
  different UUID on Windows to on other platforms.  We now swap the bytes to
  match the standard order.  With this fix, the UUIDs of existing databases
  will appear to change on Windows (except in rare "palindronic" cases).
* Fix a couple of issues to get Xapian to build and work on AIX.
* common/safeuuid.h: Remove bogus take-address-of from uuid handling code for
  NetBSD and OpenBSD.
* Under cygwin, use cygwin_conv_path() if using a new enough cygwin version,
  rather than the now deprecated cygwin_conv_to_win32_path().  Reported by
  "Haroogan" on the xapian-devel mailing list.
* common/safeuuid.h: Add missing '#include <cstdlib>' and qualify free \ 
with std.
* Fix 'unused label' warning when chert backend is disabled.
* xapian.h: Add check for Wt headers being included before us and defining
  'slots' as a macro - if they are, give a clear error advising how to work
  around this (previously compilation would fail with a confusing error).

tools:
* xapian-chert-update: Fix -b to work rather than always segfaulting (reported
  in http://bugs.debian.org/716484).
* xapian-chert-update: The documented alias --blocksize for -b has never
  actually been supported, so just drop mentions of it from --help and the man
  page.
* xapian-check:
  + Fix chert database check that first docid in each doclength chunk is more
    than the last docid in the previous chunk - previously this didn't actually
    work.
  + Fix database check not to falsely report "position table: Junk after
    position data" whenever there are 7 unused bits (7 is OK, *more* than 7
    isn't).
  + Fix to report block numbers correctly for links within the B-tree.
  + If the METAINFO key is missing, only report it once per table.
  + Fix database consistency checking to always open all the tables at the same
    revision - not doing this could lead to false errors being reported after a
    commit interrupted by the process being killed or the machine crashing.
    Reported by Joey Hess in http://bugs.debian.org/724610

examples:
* quest: Add --check-at-least option.

debug code:
* Fix assertion failure for when an OrPostList decays to an AndPostList - the
  ordering of the subqueries by estimated termfreq may not be the same as it
  was when the OrPostList was constructed, as the subqueries may themselves
  have decayed.  Reported by Michel Pelletier.
* Fix -Wcast-qual warning from GCC 4.7 when configured with --enable-log.

Log message:
Update to 1.2.15. From the changelog:

Xapian-core 1.2.15 (2013-04-16):

API:

* QueryParser/TermGenerator: Don't include CJK codepoints which are
  punctuation in N-grams.

* TermGenerator: Fix bug where we failed to generate the first bigram
  from the second sequence of N-grammable CJK characters in a piece of text.

brass backend:

* Call fdatasync()/fsync() when creating the "iambrass" file.

chert backend:

* Call fdatasync()/fsync() when creating the "iamchert" file.

flint backend:

* Call fdatasync()/fsync() when creating the "iamflint" file.

tools:

* delve: If -v is specified more than once, show even more info in some cases.

Xapian-core 1.2.14 (2013-03-14):

API:

* MSet::get_document(): Don't cache retrieved Document objects unless they
  were requested with fetch().  This avoids using a lot of memory when many
  MSet entries are retrieved.  (Fixes #604)

matcher:

* Check if a candidate document has at least the minimum weight needed
  before checking positional information, which speeds up slow phrase
  searches (partly addresses #394).

brass backend:

* Fix multipass compaction not to damage document values, and to merge the
  database stats correctly.  (fixes #615)

chert backend:

* Fix multipass compaction not to damage document values, and to merge the
  database stats correctly.  (fixes #615)

flint backend:

* Fix multipass compaction bug.  (fixes #615)

tools:

* xapian-replicate:

  + Fix handling of delays between replication events - the subtraction of the
    target time and the current time was reversed, so we wouldn't sleep when
    before the deadline, but would sleep after it for the amount we'd missed it
    by.

  + On Microsoft Windows, we no longer sleep for more than 43 years if the
    target time for a replication event had already passed.  (Fixes #472)

Xapian-core 1.2.13 (2013-01-09):

API:

* TermGenerator: Add new method TermGenerator::set_max_word_length() to allow
  this limit to be adjusted by the user.

* QueryParser: Implicitly close any unclosed brackets at the end of the query
  string.  Patch from Sehaj Singh Kalra.

* DateValueRangeProcessor: Add extra constructor overloaded form so that in
  DateValueRangeProcessor(1, "date:"), the const char * gets interpreted as
  std::string rather than bool.

matcher:

* Improved fix for #590 - count all matching LeafPostList objects with a Weight
  object rather than trying to prune at the MultiAndPostList level based on
  max_wt (if wdf is always zero for a term, BM25 gives max_wt of 0, which lead
  to us never counting that subquery.

* Fix calculation of 0.0/0.0 in some cases.  This then got used as a minimum
  weight, but it seems this gives -nan (at least on x86-64 Linux) so it may
  have been harmless in practice.

* We no longer use the highest weighted MSet entry to calculate percentages, so
  remove code which finds it.

brass backend:

* Close excess file handles before we get the fcntl lock, which avoids the
  lock being released again if one is open on the lock file.  Notably this
  avoids a situation where multiple threads in the same process could succeed
  in locking a database concurrently.

chert backend:

* Close excess file handles before we get the fcntl lock, which avoids the
  lock being released again if one is open on the lock file.  Notably this
  avoids a situation where multiple threads in the same process could succeed
  in locking a database concurrently.

flint backend:

* Close excess file handles before we get the fcntl lock, which avoids the
  lock being released again if one is open on the lock file.  Notably this
  avoids a situation where multiple threads in the same process could succeed
  in locking a database concurrently.

remote backend:

* Improve the UnimplementedError message for a MatchSpy subclass which doesn't
  implement name() so it's clearer that it is this particular subclass which
  can't be used remotely, rather than all MatchSpy objects.

documentation:

* valueranges.html: Update documentation to reflect change in Xapian 1.1.2 -
  DateValueRangeProcessor and StringValueRangeProcessor now support a prefix or
  suffix.

* Clarify that the "reverse" parameter of \ 
set_sort_by_relevance_then_value()
  and set_sort_by_relevance_then_key() only affects the ordering of the
  value/key part of the sort.

* docs/quickstart.html: Fix seriously outdated statement that Xapian doesn't
  create the database directory - that changed in 0.7.2 (released 2003-07-11).

* HACKING: Try to make it clearer we're looking for a dual-licence on submitted
  patches.

tools:

* xapian-replicate:

  + Add a --full-copy option to force a full copy to be sent.  (ticket#436)

  + Add --quiet option, and be a little more verbose by default.

  + Allow files > 32G to be be copied by replication.

  + Fix "if (fd > 0)" tests in some replication code to be "if \ 
(fd >= 0)".
    In practice this is unlikely to actually have caused problems since
    stdin is typically still open and using fd 0.

  + Simplify how we open the .DB file on the replication slave to just call
    open() once with O_CREAT, rather than once without, than stat() if that
    fails, and then again with O_CREAT|O_TRUNC if stat() doesn't show an
    ordinary file exists.

examples:

* quest:

  + New --flags command line option to allow setting arbitrary QueryParser
    flags.

  + Align option descriptions in --help output, and make the initial letter of
    such descriptions consistently lowercase.