windows: degrade to py2 behavior when reading a non-symlink as a symlink
While waiting for the push to hg-committed in WSL to complete, I ran a
`phabimport` from Windows and got this traceback:
$ hg phabimport 11313
** Unknown exception encountered with possibly-broken third-party extension "mercurial_keyring" (version N/A)
** which supports versions unknown of Mercurial.
** Please disable "mercurial_keyring" and try your action again.
** If that fixes the bug please report it to https://foss.heptapod.net/mercurial/mercurial_keyring/issues
** Python 3.9.5 (default, May 6 2021, 17:29:31) [MSC v.1928 64 bit (AMD64)]
** Mercurial Distributed SCM (version 5.9rc1+hg32.
0e2f5733563d)
** Extensions loaded: absorb, blackbox, evolve 10.3.3, extdiff, fastannotate, fix, mercurial_keyring, mq, phabblocker
20210126, phabricator, rebase, show, strip, topic 0.22.3
Traceback (most recent call last):
File "mercurial.lock", line 279, in _trylock
File "mercurial.vfs", line 202, in makelock
File "mercurial.util", line 2147, in makelock
FileExistsError: [WinError 183] Cannot create a file when that file already exists: b'hp-omen:78348' -> b'C:\\Users\\Matt\\hg/.hg/store/lock'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "<string>", line 24, in <module>
File "mercurial.dispatch", line 144, in run
File "mercurial.dispatch", line 250, in dispatch
File "mercurial.dispatch", line 294, in _rundispatch
File "mercurial.dispatch", line 470, in _runcatch
File "mercurial.dispatch", line 480, in _callcatch
File "mercurial.scmutil", line 153, in callcatch
File "mercurial.dispatch", line 460, in _runcatchfunc
File "mercurial.dispatch", line 1273, in _dispatch
File "mercurial.dispatch", line 918, in runcommand
File "mercurial.dispatch", line 1285, in _runcommand
File "mercurial.dispatch", line 1271, in <lambda>
File "mercurial.util", line 1886, in check
File "mercurial.util", line 1886, in check
File "hgext.mq", line 4239, in mqcommand
File "mercurial.util", line 1886, in check
File "mercurial.util", line 1886, in check
File "hgext.phabricator", line 314, in inner
File "hgext.phabricator", line 2222, in phabimport
File "hgext.phabricator", line 2123, in readpatch
File "hgext.phabricator", line 2199, in _write
File "mercurial.localrepo", line 2956, in lock
File "mercurial.localrepo", line 2918, in _lock
File "mercurial.lock", line 152, in trylock
File "mercurial.lock", line 283, in _trylock
File "mercurial.lock", line 314, in _readlock
File "mercurial.vfs", line 221, in readlock
File "mercurial.util", line 2163, in readlock
File "mercurial.windows", line 619, in readlink
ValueError: not a symbolic link
Both exceptions look accurate (the file exists, and the Windows side can't read
WSL side symlinks). I didn't try to reproduce this entirely within the Windows
side, but we can do better than a cryptic stacktrace. With this change, the
same scenario results in this abort:
abort: C:\Users\Matt\hg/.hg/store/lock: The file cannot be accessed by the system
When both the `push` and `phabimport` are done on the Windows side, it prints a
message about waiting for the lock, and successfully applies the patch after the
push completes.
I'm not sure if there's enough info to be able to convert the abort into the
wait scenario. As it stands now, we don't support symlinks on Windows, which
requires either a UAC Administrator level process or an opt-in in developer
mode, and there are several places where the new symlink on Windows support in
py3 was explicitly disabled in order to get tests to pass quicker.
Differential Revision: https://phab.mercurial-scm.org/D11333
#testcases skip-detection fail-if-detected
Test situations that "should" only be reproducible:
- on networked filesystems, or
- user using `hg debuglocks` to eliminate the lock file, or
- something (that doesn't respect the lock file) writing to the .hg directory
while we're running
$ hg init a
$ cd a
$ cat > "$TESTTMP/waitlock_editor.sh" <<EOF
> [ -n "\${WAITLOCK_ANNOUNCE:-}" ] && touch "\${WAITLOCK_ANNOUNCE}"
> f="\${WAITLOCK_FILE}"
> start=\`date +%s\`
> timeout=5
> while [ \\( ! -f \$f \\) -a \\( ! -L \$f \\) ]; do
> now=\`date +%s\`
> if [ "\`expr \$now - \$start\`" -gt \$timeout ]; then
> echo "timeout: \$f was not created in \$timeout seconds (it is now \$(date +%s))"
> exit 1
> fi
> sleep 0.1
> done
> if [ \$# -gt 1 ]; then
> cat "\$@"
> fi
> EOF
Things behave differently if we don't already have a 00changelog.i file when
this all starts, so let's make one.
$ echo r0 > r0
$ hg commit -qAm 'r0'
Start an hg commit that will take a while
$ EDITOR_STARTED="$(pwd)/.editor_started"
$ MISCHIEF_MANAGED="$(pwd)/.mischief_managed"
$ JOBS_FINISHED="$(pwd)/.jobs_finished"
#if fail-if-detected
$ cat >> .hg/hgrc << EOF
> [debug]
> revlog.verifyposition.changelog = fail
> EOF
#endif
$ echo foo > foo
$ (WAITLOCK_ANNOUNCE="${EDITOR_STARTED}" \
> WAITLOCK_FILE="${MISCHIEF_MANAGED}" \
> HGEDITOR="sh $TESTTMP/waitlock_editor.sh" \
> hg commit -qAm 'r1 (foo)' --edit foo > .foo_commit_out 2>&1 ; touch "${JOBS_FINISHED}") &
Wait for the "editor" to actually start
$ WAITLOCK_FILE="${EDITOR_STARTED}" sh "$TESTTMP/waitlock_editor.sh"
Break the locks, and make another commit.
$ hg debuglocks -LW
$ echo bar > bar
$ hg commit -qAm 'r2 (bar)' bar
$ hg debugrevlogindex -c
rev linkrev nodeid p1 p2
0 0 222799e2f90b 000000000000 000000000000
1 1 6f124f6007a0 222799e2f90b 000000000000
Awaken the editor from that first commit
$ touch "${MISCHIEF_MANAGED}"
And wait for it to finish
$ WAITLOCK_FILE="${JOBS_FINISHED}" sh "$TESTTMP/waitlock_editor.sh"
#if skip-detection
(Ensure there was no output)
$ cat .foo_commit_out
And observe a corrupted repository -- rev 2's linkrev is 1, which should never
happen for the changelog (the linkrev should always refer to itself).
$ hg debugrevlogindex -c
rev linkrev nodeid p1 p2
0 0 222799e2f90b 000000000000 000000000000
1 1 6f124f6007a0 222799e2f90b 000000000000
2 1 ac80e6205bb2 222799e2f90b 000000000000
#endif
#if fail-if-detected
$ cat .foo_commit_out
transaction abort!
rollback completed
note: commit message saved in .hg/last-message.txt
note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
abort: 00changelog.i: file cursor at position 249, expected 121
And no corruption in the changelog.
$ hg debugrevlogindex -c
rev linkrev nodeid p1 p2
0 0 222799e2f90b 000000000000 000000000000
1 1 6f124f6007a0 222799e2f90b 000000000000 (missing-correct-output !)
And, because of transactions, there's none in the manifestlog either.
$ hg debugrevlogindex -m
rev linkrev nodeid p1 p2
0 0 7b7020262a56 000000000000 000000000000
1 1 ad3fe36d86d9 7b7020262a56 000000000000
#endif