revlog: have an explicit "pack_header" method
Having to pass the version header when retrieving the binary version of every
single entry is a bit silly. So we extract that special logic in its own method.
This also prepare the move to newer revlog format, not storing the header within
an actual entry…
Differential Revision: https://phab.mercurial-scm.org/D10510
#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
$ chmod +x "$TESTTMP/waitlock_editor.sh"
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="$TESTTMP/waitlock_editor.sh" \
> hg commit -qAm 'r1 (foo)' --edit foo > .foo_commit_out 2>&1 ; touch "${JOBS_FINISHED}") &
Wait for the "editor" to actually start
$ WAITLOCK_FILE="${EDITOR_STARTED}" "$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="${JOBS_FINISHED}" "$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
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