Deprecation

Table of contents

Introduction

Xapian's API is fairly stable and has been polished piece by piece over time, but it still occasionally needs to be changed. This may be because a new feature has been implemented and the interface needs to allow access to it, but it may also be required in order to polish a rough edge which has been missed in earlier versions of Xapian, or simply to reflect an internal change which requires a modification to the external interface.

We aim to make such changes in a way that allows developers to work against a stable API, while avoiding the need for the Xapian developers to maintain too many old historical interface artefacts. This document describes the process we use to deprecate old pieces of the API, lists parts of the API which are currently marked as deprecated, and also describes parts of the API which have been deprecated for some time, and are now removed from the Xapian library.

It is possible for functions, methods, constants, types or even whole classes to be deprecated, but to save words this document will often use the term "features" to refer collectively to any of these types of interface items.

Deprecation Procedure

Deprecation markers

At any particular point, some parts of the C++ API will be marked as "deprecated". Deprecated features are annotated in the API headers with macros such as XAPIAN_DEPRECATED(), which will cause compilers with appropriate support (such as GCC, clang and MSVC) to emit compile-time warnings if these features are used.

If a feature is marked with one of these markers, you should avoid using it in new code, and should migrate your code to use a replacement when possible. The documentation comments for the feature, or the list at the end of this file, will describe possible alternatives to the deprecated feature.

If you want to disable deprecation warnings temporarily, you can do so by passing "-DXAPIAN_DEPRECATED(X)=X" to the compiler (the quotes are needed to protect the brackets from the shell). If your build system uses make, you might do this like so:

make 'CPPFLAGS="-DXAPIAN_DEPRECATED(X)=X"'

API and ABI compatibility

Releases are given three-part version numbers (e.g. 1.2.9), the three parts being termed "major" (1), "minor" (2), and "revision" (9). Releases with the same major and minor version are termed a "release series".

For Xapian releases 1.0.0 and higher, an even minor version indicates a stable release series, while an odd minor version indicates a development release series.

Within a stable release series, we strive to maintain API and ABI forwards compatibility. This means that an application written and compiled against version X.Y.a of Xapian should work, without any source changes or need to recompile, with a later version X.Y.b, for all b >= a. Stable releases which increase the minor or major version number will usually change the ABI incompatibly (so that code will need to be recompiled against the newer release series. They may also make incompatible API changes, though we will attempt to do this in a way which makes it reasonably easy to migrate applications, and document how to do so in this document.

It is possible that a feature may be marked as deprecated within a minor release series - that is from version X.Y.c onwards, where c is not zero. The API and ABI will not be changed by this deprecation, since the feature will still be available in the API (though the change may cause the compiler to emit new warnings when rebuilding code which uses the now-deprecated feature).

Users should generally be able to expect working code which uses Xapian not to stop working without reason. We attempt to codify this in the following policy, but we reserve the right not to slavishly follow this. The spirit of the rule should kept in mind - for example if we discovered a feature which didn't actually work, making an incompatible API change at the next ABI bump would be reasonable.

Normally a feature will be supported after being deprecated for an entire stable release series. For example, if a feature is deprecated in release 1.2.0, it will be supported for the entire 1.2.x release series, and removed in development release 1.3.0. If a feature is deprecated in release 1.2.1, it will be supported for the 1.2.x and 1.4.x stable release series (and of course the 1.3.x release series in between), and won't be removed until 1.5.0.

Experimental features

During a development release series (such as the 1.1.x series), some features may be marked as "experimental". Such features are liable to change without going through the normal deprecation procedure. This includes changing on-disk formats for data stored by the feature, and breaking API and ABI compatibility between releases for the feature. Such features are included in releases to get wider use and corresponding feedback about them.

Deprecation in the bindings

When the Xapian API changes, the interface provided by the Xapian bindings will usually change in step. In addition, it is sometimes necessary to change the way in which Xapian is wrapped by bindings - for example, to provide a better convenience wrapper for iterators in Python. Again, we aim to ensure that an application written (and compiled, if the language being bound is a compiled language) for version X.Y.a of Xapian should work without any changes or need to recompile, with a later version X.Y.b, for all a <= b.

However, the bindings are a little less mature than the core C++ API, so we don't intend to give the same guarantee that a feature present and not deprecated in version X.Y.a will work in all versions X+1.Y.b. In other words, we may remove features which have been deprecated without waiting for an entire release series to pass.

Any planned deprecations will be documented in the list of deprecations and removed features at the end of this file.

Support for Other Software

Support for other software doesn't follow the same deprecation rules as for API features.

Our guiding principle for supporting version of other software is that we don't aim to actively support versions which are no longer supported "upstream".

So Xapian 1.1.0 doesn't support PHP4 because the PHP team no longer did when it was released. By the API deprecation rules we should have announced this when Xapian 1.0.0 was released, but we don't have control over when and to what timescales other software providers discontinue support for older versions.

Sometimes we can support such versions without extra effort (e.g. Tcl's stubs mechanism means Tcl 8.1 probably still works, even though the last 8.1.x release was over a decade ago), and in some cases Linux distros continue to support software after upstream stops.

But in most cases keeping support around is a maintenance overhead and we'd rather spend our time on more useful things.

Note that there's no guarantee that we will support and continue to support versions just because upstream still does. For example, we ceased providing backported packages for Ubuntu dapper with Xapian 1.1.0 - in this case, it's because we felt that if you're conservative enough to run dapper, you'd probably prefer to stick with 1.0.x until you upgrade to hardy (the next Ubuntu LTS release). But we may decide not to support versions for other reasons too.

How to avoid using deprecated features

We recommend taking the following steps to avoid depending on deprecated features when writing your applications:

  • If at all possible, test compile your project using a compiler which supports warnings about deprecated features (such as GCC 3.1 or later), and check for such warnings. Use the -Werror flag to GCC to ensure that you don't miss any of them.
  • Check the NEWS file for each new release for details of any new features which are deprecated in the release.
  • Check the documentation comments, or the automatically extracted API documentation, for each feature you use in your application. This documentation will indicate features which are deprecated, or planned for deprecation.
  • For applications which are not written in C++, there is currently no equivalent of the XAPIAN_DEPRECATED macro for the bindings, and thus there is no way for the bindings to give a warning if a deprecated feature is used. This would be a nice addition for those languages in which there is a reasonable way to give such warnings. Until such a feature is implemented, all application writers using the bindings can do is to check the list of deprecated features in each new release, or lookup the features they are using in the list at the end of this file.

Features currently marked for deprecation

Native C++ API

Deprecated Remove Feature name Upgrade suggestion and comments
1.3.0 1.5.0 Xapian::timeout typedef Use unsigned instead, which should also work with older Xapian releases.
1.3.0 1.5.0 Xapian::percent typedef Use int instead, which should also work with older Xapian releases.
1.3.0 1.5.0 Xapian::weight typedef Use double instead, which should also work with older Xapian releases.
1.3.1 1.5.0 Xapian::ErrorHandler We feel the current ErrorHandler API doesn't work at the right level (it only works in Enquire, whereas you should be able to handle errors at the Database level too) and we can't find any evidence that people are actually using it. So we've made the API a no-op and marked it as deprecated. The hope is to replace it with something better thought out, probably during the 1.4.x release series. There's some further thoughts at https://trac.xapian.org/ticket/3#comment:8
1.3.2 1.5.0 Xapian::Auto::open_stub() Use the constructor with Xapian::DB_BACKEND_STUB flag (new in 1.3.2) instead.
1.3.2 1.5.0 Xapian::Chert::open() Use the constructor with Xapian::DB_BACKEND_CHERT flag (new in 1.3.2) instead.
1.3.2 1.5.0 Xapian::Enquire::get_eset() overloaded form taking k parameter. Use Xapian::Enquire::set_expansion_scheme() to specify the algorithm which get_eset() should use, along with any parameters (added in 1.3.2).
1.3.3 1.5.0 Xapian::QueryParser::set_max_wildcard_expansion() Use Xapian::QueryParser::set_max_expansion() instead.
1.3.4 1.5.0 Xapian::Compactor methods set_block_size(), set_renumber(), set_multipass(), set_compaction_level(), set_destdir(), add_source()` and ``compact(). Use the Xapian::Database::compact() method instead. The Xapian::Compactor class is now just a subclassable functor class to allow access to progress messages and control over merging of user metadata.
1.3.5 1.5.0 Xapian::ValuePostingSource public member variables Use the respective getter and setter methods instead, added in 1.3.5 and 1.2.23.
1.3.5 1.5.0 Xapian::InMemory::open() Use the constructor with Xapian::DB_BACKEND_INMEMORY flag (new in 1.3.5) instead.
1.3.6 1.5.0 Xapian::WritableDatabase::flush() Use Xapian::WritableDatabase::commit() instead (available since 1.1.0).
1.3.6 1.5.0 Subclassing Xapian::ValueRangeProcessor Subclass Xapian::RangeProcessor instead, and return a Xapian::Query from operator()() (added in 1.3.6).
1.3.6 1.5.0 Xapian::DateValueRangeProcessor Use Xapian::DateRangeProcessor instead (added in 1.3.6).
1.3.6 1.5.0 Xapian::NumberValueRangeProcessor Use Xapian::NumberRangeProcessor instead (added in 1.3.6).
1.3.6 1.5.0 Xapian::StringValueRangeProcessor Use Xapian::RangeProcessor instead, which includes equivalent support for prefix/suffix checking (added in 1.3.6).
1.3.6 1.5.0 Xapian::QueryParser::add_valuerangeprocessor() Use Xapian::QueryParser::add_rangeprocessor() instead, with a Xapian::RangeProcessor object instead of a Xapian::ValueRangeProcessor object (added in 1.3.6).

Bindings

Deprecated Remove Language Feature name Upgrade suggestion and comments
1.2.5 1.5.0 Python MSet.items Iterate the MSet object itself instead.
1.2.5 1.5.0 Python ESet.items Iterate the ESet object itself instead.

Omega

Deprecated Remove Feature name Upgrade suggestion and comments
1.2.4 1.5.0 omindex command line long option --preserve-nonduplicates. Renamed to --no-delete, which works in 1.2.4 and later.
1.2.5 1.5.0 $set{spelling,true} Use $set{flag_spelling_suggestion,true} instead.

Features removed from Xapian

Native C++ API

Removed Feature name Upgrade suggestion and comments
1.0.0 QueryParser::set_stemming_options()

Use set_stemmer(), set_stemming_strategy() and/or set_stopper() instead:

  • set_stemming_options("") becomes set_stemming_strategy(Xapian::QueryParser::STEM_NONE)
  • set_stemming_options("none") becomes set_stemming_strategy(Xapian::QueryParser::STEM_NONE)
  • set_stemming_options(LANG) becomes set_stemmer(Xapian::Stem(LANG) and set_stemming_strategy(Xapian::QueryParser::STEM_SOME)
  • set_stemming_options(LANG, false) becomes set_stemmer(Xapian::Stem(LANG) and set_stemming_strategy(Xapian::QueryParser::STEM_SOME)
  • set_stemming_options(LANG, true) becomes set_stemmer(Xapian::Stem(LANG) and set_stemming_strategy(Xapian::QueryParser::STEM_ALL)

If a third parameter is passed, set_stopper(PARAM3) and treat the first two parameters as above.

1.0.0 Enquire::set_sort_forward()

Use Enquire::set_docid_order() instead:

  • set_sort_forward(true) becomes set_docid_order(ASCENDING)
  • set_sort_forward(false) becomes set_docid_order(DESCENDING)
1.0.0 Enquire::set_sorting()

Use Enquire::set_sort_by_relevance(), Enquire::set_sort_by_value(), or Enquire::set_sort_by_value_then_relevance() instead.

  • set_sorting(KEY, 1) becomes set_sort_by_value(KEY)
  • set_sorting(KEY, 1, false) becomes set_sort_by_value(KEY)
  • set_sorting(KEY, 1, true) becomes set_sort_by_value_then_relevance(KEY)
  • set_sorting(ANYTHING, 0) becomes set_sort_by_relevance()
  • set_sorting(Xapian::BAD_VALUENO, ANYTHING) becomes set_sort_by_relevance()
1.0.0 Stem::stem_word(word) Use Stem::operator()(word) instead.
1.0.0 Auto::open(path) Use the Database(path) constructor instead.
1.0.0 Auto::open(path, action) Use the WritableDatabase(path, action) constructor instead.
1.0.0 Query::is_empty() Use Query::empty() instead.
1.0.0 Document::add_term_nopos() Use Document::add_term() instead.
1.0.0 Enquire::set_bias() Use PostingSource instead (new in 1.2).
1.0.0 ExpandDecider::operator() Return type is now bool not int.
1.0.0 MatchDecider::operator() Return type is now bool not int.
1.0.0 Error::get_type() Return type is now const char * not std::string. Most existing code won't need changes, but if it does the simplest fix is to write std::string(e.get_type()) instead of e.get_type().
1.0.0 <xapian/output.h> Use cout << obj.get_description(); instead of cout << obj;
1.0.0 Several constructors marked as explicit. Explicitly create the object type required, for example use Xapian::Enquire enq(Xapian::Database(path)); instead of Xapian::Enquire enq(path);
1.0.0 QueryParser::parse_query() throwing const char * exception. Catch Xapian::QueryParserError instead of const char *, and call get_msg() on the caught object. If you need to build with either version, catch both (you'll need to compile the part which catches QueryParserError conditionally, since this exception isn't present in the 0.9 release series).
1.1.0 xapian_version_string() Use version_string() instead.
1.1.0 xapian_major_version() Use major_version() instead.
1.1.0 xapian_minor_version() Use minor_version() instead.
1.1.0 xapian_revision() Use revision() instead.
1.1.0 Enquire::include_query_terms Use Enquire::INCLUDE_QUERY_TERMS instead.
1.1.0 Enquire::use_exact_termfreq Use Enquire::USE_EXACT_TERMFREQ instead.
1.1.0 Error::get_errno() Use Error::get_error_string() instead.
1.1.0 Enquire::register_match_decider() This method didn't do anything, so just remove calls to it!
1.1.0 Query::Query(Query::op, Query) This constructor isn't useful for any currently implemented Query::op.
1.1.0 The Quartz backend Use the Chert backend instead.
1.1.0 Quartz::open() Use Chert::open() instead.
1.1.0 quartzcheck Use xapian-check instead.
1.1.0 quartzcompact Use xapian-compact instead.
1.1.0 quartzdump Use xapian-inspect instead.
1.1.0 configure --enable-debug configure --enable-assertions
1.1.0 configure --enable-debug=full configure --enable-assertions --enable-log
1.1.0 configure --enable-debug=partial configure --enable-assertions=partial
1.1.0 configure --enable-debug=profile configure --enable-log=profile
1.1.0 configure --enable-debug-verbose configure --enable-log
1.1.0 Database::positionlist_begin() throwing RangeError if the term specified doesn't index the document specified. This check is quite expensive, and often you don't care. If you do it's easy to check - just open a TermListIterator for the document and use skip_to() to check if the term is there.
1.1.0 Database::positionlist_begin() throwing DocNotFoundError if the document specified doesn't exist. This check is quite expensive, and often you don't care. If you do, it's easy to check - just call Database::get_document() with the specified document ID.
1.1.5 delve -k Accepted as an undocumented alias for -V since 0.9.10 for compatibility with 0.9.9 and earlier. Just use -V instead.
1.3.0 The Flint backend Use the Chert backend instead.
1.3.0 Flint::open() Use Chert::open() instead.
1.3.0 xapian-chert-update Install Xapian 1.2.x (where x >= 5) to update chert databases from 1.1.3 and earlier.
1.3.0 Default second parameter to Enquire sorting functions.

The parameter name was ascending and defaulted to true. However ascending=false gave what you'd expect the default sort order to be (and probably think of as ascending) while ascending=true gave the reverse (descending) order. For sanity, we renamed the parameter to reverse and deprecated the default value. In the more distant future, we'll probably add a default again, but of false instead.

The methods affected are: Enquire::set_sort_by_value(Xapian::valueno sort_key) Enquire::set_sort_by_key(Xapian::Sorter * sorter) Enquire::set_sort_by_value_then_relevance(Xapian::valueno sort_key) Enquire::set_sort_by_key_then_relevance(Xapian::Sorter * sorter) Enquire::set_sort_by_relevance_then_value(Xapian::valueno sort_key) Enquire::set_sort_by_relevance_then_key(Xapian::Sorter * sorter)

To update them, just add a second parameter with value true to each of the above calls. For the methods which take a Xapian::Sorter object, you'll also need to migrate to Xapian::KeyMaker (see below).

1.3.0 Sorter abstract base class. Use KeyMaker class instead, which has the same semantics, but has been renamed to indicate that the keys produced may be used for purposes other than sorting (we plan to allow collapsing on generated keys in the future).
1.3.0 MultiValueSorter class.

Use MultiValueKeyMaker class instead. Note that MultiValueSorter::add() becomes MultiValueKeyMaker::add_value(), but the sense of the direction flag is reversed (to be consistent with Enquire::set_sort_by_value()), so:

MultiValueSorter sorter;
// Primary ordering is forwards on value 4.
sorter.add(4);
// Secondary ordering is reverse on value 5.
sorter.add(5, false);

becomes:

MultiValueKeyMaker sorter;
// Primary ordering is forwards on value 4.
sorter.add_value(4);
// Secondary ordering is reverse on value 5.
sorter.add_value(5, true);
1.3.0 matchspy parameter to Enquire::get_mset() Use the newer MatchSpy class and Enquire::add_matchspy() method instead.
1.3.0 Xapian::Query::unserialise() throws Xapian::SerialisationError not Xapian::InvalidArgumentError for errors in serialised data To be compatible with older and newer Xapian, you can catch both exceptions.
1.3.2 The Brass backend Use the Glass backend instead.
1.3.2 Xapian::Brass::open() Use the constructor with Xapian::DB_BACKEND_GLASS flag (new in 1.3.2) instead.
1.3.4 Copy constructors and assignment operators for classes: Xapian::ExpandDecider, Xapian::FieldProcessor (new in 1.3.1), Xapian::KeyMaker, Xapian::MatchDecider, Xapian::StemImplementation, Xapian::Stopper and Xapian::ValueRangeProcessor. We think it was a mistake that implicit copy constructors and assignment operators were being provided for these functor classes - it's hard to use them correctly, but easy to use them in ways which compile but don't work correctly, and we doubt anyone is intentionally using them, so we've simply removed them. For more information, see https://trac.xapian.org/ticket/681
1.3.5 Xapian::DBCHECK_SHOW_BITMAP Use Xapian::DBCHECK_SHOW_FREELIST (added in 1.3.2) instead. Xapian::DBCHECK_SHOW_BITMAP was added in 1.3.0, so has never been in a stable release.

Bindings

Removed Language Feature name Upgrade suggestion and comments
1.0.0 SWIG [1] Enquire::set_sort_forward()

Use Enquire::set_docid_order() instead.

  • set_sort_forward(true) becomes set_docid_order(ASCENDING)
  • set_sort_forward(false) becomes set_docid_order(DESCENDING)
1.0.0 SWIG [1] Enquire::set_sorting()

Use Enquire::set_sort_by_relevance(), Enquire::set_sort_by_value() or Enquire::set_sort_by_value_then_relevance() instead.

  • set_sorting(KEY, 1) becomes set_sort_by_value(KEY)
  • set_sorting(KEY, 1, false) becomes ``set_sort_by_value(KEY)
  • set_sorting(KEY, 1, true) becomes set_sort_by_value_then_relevance(KEY)
  • set_sorting(ANYTHING, 0) becomes set_sort_by_relevance()
  • set_sorting(Xapian::BAD_VALUENO, ANYTHING) becomes set_sort_by_relevance()
1.0.0 SWIG [1] Auto::open(path) Use the Database(path) constructor instead.
1.0.0 SWIG [1] Auto::open(path, action) Use the WritableDatabase(path, action) constructor instead.
1.0.0 SWIG [3] MSet::is_empty() Use MSet::empty() instead.
1.0.0 SWIG [3] ESet::is_empty() Use ESet::empty() instead.
1.0.0 SWIG [3] RSet::is_empty() Use RSet::empty() instead.
1.0.0 SWIG [3] Query::is_empty() Use Query::empty() instead.
1.0.0 SWIG [1] Document::add_term_nopos() Use Document::add_term() instead.
1.0.0 CSharp ExpandDecider::Apply() Return type is now bool instead of int.
1.0.0 CSharp MatchDecider::Apply() Return type is now bool instead of int.
1.0.0 SWIG [1] Stem::stem_word(word) Use Stem::operator()(word) instead. [4]
1.1.0 SWIG [1] xapian_version_string() Use version_string() instead.
1.1.0 SWIG [1] xapian_major_version() Use major_version() instead.
1.1.0 SWIG [1] xapian_minor_version() Use minor_version() instead.
1.1.0 SWIG [1] xapian_revision() Use revision() instead.
1.1.0 SWIG [1] ESetIterator::get_termname() Use ESetIterator::get_term() instead. This change is intended to bring the ESet iterators in line with other term iterators, which all support get_term() instead of get_termname().
1.1.0 Python get_description() All get_description() methods have been renamed to __str__(), so the normal python str() function can be used.
1.1.0 Python MSetItem.get_*() All these methods are deprecated, in favour of properties. To convert, just change msetitem.get_FOO() to msetitem.FOO
1.1.0 Python Enquire.get_matching_terms Replaced by Enquire.matching_terms, for consistency with rest of Python API. Note: an Enquire.get_matching_terms method existed in releases up-to and including 1.2.4, but this was actually an old implementation which only accepted a MSetIterator as a parameter, and would have failed with code written expecting the version in 1.0.0. It was fully removed after release 1.2.4.
1.1.0 SWIG [1] Error::get_errno() Use Error::get_error_string() instead.
1.1.0 SWIG [2] MSet::get_document_id() Use MSet::get_docid() instead.
1.2.0 Python mset[i][xapian.MSET_DID] etc This was inadvertently removed in 1.2.0, but not noticed until 1.2.5, by which point it no longer seemed worthwhile to reinstate it. Please use the property API instead, e.g. mset[i].docid, mset[i].weight, etc.
1.2.5 Python if idx in mset This was nominally implemented, but never actually worked. Since nobody seems to have noticed in 3.5 years, we just removed it. If you have uses (which were presumably never called), you can replace them with: if idx >= 0 and idx < len(mset)
1.3.0 Python Non-pythonic iterators Use the pythonic iterators instead.
1.3.0 Python Stem_get_available_languages Use Stem.get_available_languages instead (static method instead of function)
[1](1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) This affects all SWIG generated bindings (currently: Python, PHP, Ruby, Tcl8 and CSharp)
[2]This affects all SWIG-generated bindings except those for Ruby, support for which was added after the function was deprecated in Xapian-core.
[3](1, 2, 3, 4) This affects all SWIG generated bindings except those for Ruby, which was added after the function was deprecated in Xapian-core, and PHP, where empty is a reserved word (and therefore, the method remains "is_empty").
[4]Python handles this like C++. Ruby renames it to 'call' (idiomatic Ruby). PHP renames it to 'apply'. CSharp to 'Apply' (delegates could probably be used to provide C++-like functor syntax, but that's effort and it seems debatable if it would actually be more natural to a C# programmer). Tcl8 renames it to 'apply' - need to ask a Tcl type if that's the best solution.

Omega

Removed Feature name Upgrade suggestion and comments
1.0.0 $freqs Use $map{$queryterms,$_:&nbsp;$nice{$freq{$_}}} instead.
1.0.0 scriptindex -u -u was ignored for compatibility with 0.7.5 and earlier, so just remove it.
1.0.0 scriptindex -q -q was ignored for compatibility with 0.6.1 and earlier, so just remove it.
1.1.0 scriptindex index=nopos Use indexnopos instead.
1.3.0 OLDP CGI parameter Use xP CGI parameter instead (direct replacement), which has been supported since at least 0.5.0.