Comment 0 for bug 1842118

Ubuntu is stuck with tracker 2.1.8 and tracker miners 2.1.6, while GNOME 3.34 will ship versions 2.3.0 of both.

Main changes since archive version, in tracker:
    - Support for storing Musicbrainz metadata in the multimedia ontology.
  - Fix detection of files that need writeback
  - Fix crashes and invalid memory writes
  - Fixed initialization of virtual tables
  - Fixed segmentation fault in libtracker-miner
  - Don't try to create JSON-LD nodes with unsigned integers
  - Handle correctly backreferences in TrackerResource tree
  - Fixed handling doubles with exponents in SPARQL
  - Don't limit to specific desktop environments
  - Fix unichar unescaping
  - Correctly Handle BIND in first place of a triples block
  - Fix possible deadlock on WAL checkpoint
  - Fix some double values not being deleted
  - Fixed CHANGES_DONE_HINT handling in TrackerMonitor
  - Ported data generator utilities to python3
  - Ported functional tests to python3, reformatted to PEP-8
  - Correctly apply ignored-directories-with-content filter on monitor updates
  - Multiple memory leak and memory corruption fixes
  - New SPARQL parser, able to generate SQL that is generally more readable
    and at places performs better. Multiple buglets fixed in the process
  - Much improved support of SPARQL1.1 features and syntax that was missing:
    * Property paths: Allowing to match connectivity between two resources
      by an arbitrary length path. There is a number of supported operators
      (alternative, sequence, oneOrMany, ...) that can be combined, e.g:

      SELECT ?s ?p { ?s ^(nfo:belongsToContainer*)/(nie:url|nie:title) ?p }

      Only the negated path operator (!) is not supported at the moment.

    * Support for fully unrestricted queries, eg:

      SELECT ?s ?p ?o { ?s ?p ?o } ORDER BY ?o ?p ?s

      Queries with unrestricted predicate (?p in the example above) were
      just supported in a very restricted set of situations. All those
      limitations are gone.
    * MINUS allows subtracting the solutions that match the given triples
      template, eg:

      SELECT ?s { ?s a nfo:Media } MINUS { ?s a nfo:MusicPiece }

  - Support for prepared statements. TrackerSparqlStatement can be built
    with SELECT queries containing (custom) ~var syntax, and updating
    their values before obtaining a cursor.
  - tracker-store now automatically shuts down on inactivity.
  - More property paths supported, new operators supported are -, +, ? and |,
    only the ! operator is not supported yet.
  - Improve error handling in DBus backend
  - New SPARQL parser, able to support more 1.1 features and generating
    friendlier SQL at places. There is initial support for property
    paths (/ and ^), and other missing 1.1 syntax (MINUS, SHA384, ...).
    More improvements are expected to happen in the future thanks to this.
  - Support for prepared statements. TrackerSparqlStatement can be built
    with SELECT queries containing (custom) ~var syntax, and updating
    their values before obtaining a cursor.

NEWS upstream file changes:
 https://gitlab.gnome.org/GNOME/tracker/compare/2.1.8...2.2.99.0#9f621eb5fd3bcb2fa5c7bd228c9b1ad42edc46c8

While in tracker-miners:

  - Support for reading Musicbrainz metadata from audio files.
  - Tracker Writeback now uses GStreamer to write metadata to audio files,
    instead of depending on taglib directly.
  - Directories will now be ignored if they contain a file named `.nomedia`.
    A file named `.trackerignore` has the same effect, but the `.nomedia` file
    brings us in line with Android.
  - Removed obsolete 'max-media-art-width' setting.
  - Functional tests now use python3
  - Fix text extractor handling of non-existent files
  - Fix indexing of tracks in FLAC files
  - Whitelist syscall fadvise64_64
  - Fix failed functional tests being reported as successful
  - Fixes to desktop file indexing
  - The functionality of tracker-miner-apps has been adopted by
    tracker-miner-fs/tracker-extract.
  - Updated tracker-miner-fs and tracker-miner-rss to use TrackerResource

NEWS upstream file changes:
 https://gitlab.gnome.org/GNOME/tracker-miners/compare/2.1.6...2.2.99.0#9f621eb5fd3bcb2fa5c7bd228c9b1ad42edc46c8

So changes are quite a lot and with lots of improvements, that it's quite important to test a bit more before next LTS, so having in 19.10 would be smart.