extensions: refuse to load extensions if minimum hg version not met
As the author of several 3rd party extensions, I frequently see bug
reports from users attempting to run my extension with an old version
of Mercurial that I no longer support in my extension. Oftentimes, the
extension will import just fine. But as soon as we run extsetup(),
reposetup(), or get into the guts of a wrapped function, we encounter
an exception and abort. Today, Mercurial will print a message about
extensions that don't have a "testedwith" declaring explicit
compatibility with the current version.
The existing mechanism is a good start. But it isn't as robust as I
would like. Specifically, Mercurial assumes compatibility by default.
This means extension authors must perform compatibility checking in
their extsetup() or we wait and see if we encounter an abort at
runtime. And, compatibility checking can involve a lot of code and
lots of error checking. It's a lot of effort for extension authors.
Oftentimes, extension authors know which versions of Mercurial there
extension works on and more importantly where it is broken.
This patch introduces a magic "minimumhgversion" attribute in
extensions. When found, the extension loading mechanism will compare
the declared version against the current Mercurial version. If the
extension explicitly states we require a newer Mercurial version, a
warning is printed and the extension isn't loaded beyond importing
the Python module. This causes a graceful failure while alerting
the user of the compatibility issue.
I would be receptive to the idea of making the failure more fatal.
However, care would need to be taken to not criple every hg command.
e.g. the user may use `hg config` to fix the hgrc and if we aborted
trying to run that, the user would effectively be locked out of `hg`!
A potential future improvement to this functionality would be to catch
ImportError for the extension/module and parse the source code for
"minimumhgversion = 'XXX'" and do similar checking. This way we could
give more information about why the extension failed to load.
# enable bundle2 in advance
$ cat << EOF >> $HGRCPATH
> [format]
> usegeneraldelta=yes
> EOF
$ mkdir part1
$ cd part1
$ hg init
$ echo a > a
$ hg add a
$ hg commit -m "1"
$ hg status
$ hg copy a b
$ hg --config ui.portablefilenames=abort copy a con.xml
abort: filename contains 'con', which is reserved on Windows: 'con.xml'
[255]
$ hg status
A b
$ hg sum
parent: 0:c19d34741b0a tip
1
branch: default
commit: 1 copied
update: (current)
phases: 1 draft
$ hg --debug commit -m "2"
committing files:
b
b: copy a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
committing manifest
committing changelog
committed changeset 1:93580a2c28a50a56f63526fb305067e6fbf739c4
we should see two history entries
$ hg history -v
changeset: 1:93580a2c28a5
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
files: b
description:
2
changeset: 0:c19d34741b0a
user: test
date: Thu Jan 01 00:00:00 1970 +0000
files: a
description:
1
we should see one log entry for a
$ hg log a
changeset: 0:c19d34741b0a
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 1
this should show a revision linked to changeset 0
$ hg debugindex a
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 3 ..... 0 b789fdd96dc2 000000000000 000000000000 (re)
we should see one log entry for b
$ hg log b
changeset: 1:93580a2c28a5
tag: tip
user: test
date: Thu Jan 01 00:00:00 1970 +0000
summary: 2
this should show a revision linked to changeset 1
$ hg debugindex b
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 65 ..... 1 37d9b5d994ea 000000000000 000000000000 (re)
this should show the rename information in the metadata
$ hg debugdata b 0 | head -3 | tail -2
copy: a
copyrev: b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3
$ md5sum.py .hg/store/data/b.i
44913824c8f5890ae218f9829535922e .hg/store/data/b.i
$ hg cat b > bsum
$ md5sum.py bsum
60b725f10c9c85c70d97880dfe8191b3 bsum
$ hg cat a > asum
$ md5sum.py asum
60b725f10c9c85c70d97880dfe8191b3 asum
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
2 files, 2 changesets, 2 total revisions
$ cd ..
$ mkdir part2
$ cd part2
$ hg init
$ echo foo > foo
should fail - foo is not managed
$ hg mv foo bar
foo: not copying - file is not managed
abort: no files to copy
[255]
$ hg st -A
? foo
$ hg add foo
dry-run; print a warning that this is not a real copy; foo is added
$ hg mv --dry-run foo bar
foo has not been committed yet, so no copy data will be stored for bar.
$ hg st -A
A foo
should print a warning that this is not a real copy; bar is added
$ hg mv foo bar
foo has not been committed yet, so no copy data will be stored for bar.
$ hg st -A
A bar
should print a warning that this is not a real copy; foo is added
$ hg cp bar foo
bar has not been committed yet, so no copy data will be stored for foo.
$ hg rm -f bar
$ rm bar
$ hg st -A
A foo
$ hg commit -m1
moving a missing file
$ rm foo
$ hg mv foo foo3
foo: deleted in working directory
foo3 does not exist!
$ hg up -qC .
copy --after to a nonexistent target filename
$ hg cp -A foo dummy
foo: not recording copy - dummy does not exist
dry-run; should show that foo is clean
$ hg copy --dry-run foo bar
$ hg st -A
C foo
should show copy
$ hg copy foo bar
$ hg st -C
A bar
foo
shouldn't show copy
$ hg commit -m2
$ hg st -C
should match
$ hg debugindex foo
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 5 ..... 0 2ed2a3912a0b 000000000000 000000000000 (re)
$ hg debugrename bar
bar renamed from foo:2ed2a3912a0b24502043eae84ee4b279c18b90dd
$ echo bleah > foo
$ echo quux > bar
$ hg commit -m3
should not be renamed
$ hg debugrename bar
bar not renamed
$ hg copy -f foo bar
should show copy
$ hg st -C
M bar
foo
XXX: filtering lfilesrepo.status() in 3.3-rc causes the copy source to not be
displayed.
$ hg st -C --config extensions.largefiles=
M bar
foo
$ hg commit -m3
should show no parents for tip
$ hg debugindex bar
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 69 ..... 1 7711d36246cc 000000000000 000000000000 (re)
1 69 6 ..... 2 bdf70a2b8d03 7711d36246cc 000000000000 (re)
2 75 71 ..... 3 b2558327ea8d 000000000000 000000000000 (re)
should match
$ hg debugindex foo
rev offset length ..... linkrev nodeid p1 p2 (re)
0 0 5 ..... 0 2ed2a3912a0b 000000000000 000000000000 (re)
1 5 7 ..... 2 dd12c926cf16 2ed2a3912a0b 000000000000 (re)
$ hg debugrename bar
bar renamed from foo:dd12c926cf165e3eb4cf87b084955cb617221c17
should show no copies
$ hg st -C
copy --after on an added file
$ cp bar baz
$ hg add baz
$ hg cp -A bar baz
$ hg st -C
A baz
bar
foo was clean:
$ hg st -AC foo
C foo
but it's considered modified after a copy --after --force
$ hg copy -Af bar foo
$ hg st -AC foo
M foo
bar
$ cd ..