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| author | David Kalnischkies <david@kalnischkies.de> | 2016-05-08 11:58:36 +0200 |
|---|---|---|
| committer | David Kalnischkies <david@kalnischkies.de> | 2016-05-08 13:39:32 +0200 |
| commit | 7f2d1eef183dbebaaabe07a296d9a97e9cfd0f4a (patch) | |
| tree | d4b783fa9946462547b6dda8ae0214c2631835bd /doc | |
| parent | 7c1dca1439b956a085b09c73fdbe5a66af20241b (diff) | |
implement Fallback-Of for IndexTargets
Sometimes index files are in different locations in a repository as it
is currently the case for Contents files which are per-component in
Debian, but aren't in Ubuntu. This has historic reasons and is perhaps
changed soon, but such cases of transitions can always happen in the
future again, so we should prepare:
Introduced is a new field declaring that the current item should only be
downloaded if the mentioned item wasn't allowing for transitions without
a flagday in clients and archives.
This isn't implemented 'simpler' with multiple MetaKeys as items (could)
change their descriptions and perhaps also other configuration bits with
their location.
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/acquire-additional-files.txt | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/doc/acquire-additional-files.txt b/doc/acquire-additional-files.txt index 68af9a5b0..19c3deb13 100644 --- a/doc/acquire-additional-files.txt +++ b/doc/acquire-additional-files.txt @@ -90,6 +90,11 @@ Additional optional properties: have to ensure your front-end can deal with all compressed fileformats supported by apt (libapt users can e.g. use FileFd, others can use the cat-file command of /usr/lib/apt/apt-helper). +* Fallback-Of: Is by default not set. If it is set and specifies another + target name (see Created-By) which was found in the Release file the + download of this target will be skipped. This can be used to implement + fallback(chain)s to allow transitions like the rename of target files. + The behavior if cycles are formed with Fallback-Of is undefined! * flat{MetaKey,Description}: APT supports two types of repositories: dists-style repositories which are the default and by far the most common which are named after the fact that the files are in an @@ -204,11 +209,11 @@ uppercase and wrapped in $(), as in the configuration file. To get all the filenames of all Translation-en files you can e.g. call: apt-get indextargets --format '$(FILENAME)' "Created-By: Translations" "Language: en" -The line-based filtering and the formating is rather crude and feature- +The line-based filtering and the formatting is rather crude and feature- less by design: The default format is Debians standard format deb822 (in particular: Field names are case-insensitive and the order of fields in the stanza is undefined), so instead of apt reimplementing powerful -filters and formating for this command, it is recommend to use piping +filters and formatting for this command, it is recommend to use piping and dedicated tools like 'grep-dctrl' if you need more than the basics provided. |