fast-import: introduce "feature notes" command

Here is a 'feature' command for streams to use to require support for
the notemodify (N) command.

When the 'feature' facility was introduced (v1.7.0-rc0~95^2~4,
2009-12-04), the notes import feature was old news (v1.6.6-rc0~21^2~8,
2009-10-09) and it was not obvious it deserved to be a named feature.
But now that is clear, since all major non-git fast-import backends
lack support for it.

Details: on git version with this patch applied, any "feature notes"
command in the features/options section at the beginning of a stream
will be treated as a no-op.  On fast-import implementations without
the feature (and older git versions), the command instead errors out
with a message like

	This version of fast-import does not support feature notes.

So by declaring use of notes at the beginning of a stream, frontends
can avoid wasting time and other resources when the backend does not
support notes.  (This would be especially important for backends that
do not support rewinding history after a botched import.)

Improved-by: Thomas Rast <trast@student.ethz.ch>
Improved-by: Sverre Rabbelier <srabbelier@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jonathan Nieder 2011-02-09 16:43:57 -06:00 committed by Junio C Hamano
parent 68595cd442
commit 547e8b9205
3 changed files with 9 additions and 0 deletions

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@ -898,6 +898,12 @@ import-marks::
second, an --import-marks= command-line option overrides
any "feature import-marks" command in the stream.
notes::
Require that the backend support the 'notemodify' (N)
subcommand to the 'commit' command.
Versions of fast-import not supporting notes will exit
with a message indicating so.
`option`
~~~~~~~~
Processes the specified option so that git fast-import behaves in a

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@ -2821,6 +2821,8 @@ static int parse_one_feature(const char *feature, int from_stream)
relative_marks_paths = 0;
} else if (!prefixcmp(feature, "force")) {
force_update = 1;
} else if (!strcmp(feature, "notes")) {
; /* do nothing; we have the feature */
} else {
return 0;
}

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@ -120,6 +120,7 @@ test_expect_success 'add notes with simple M command' '
test_tick
cat >input <<INPUT_END
feature notes
commit refs/notes/test
committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
data <<COMMIT