lock: while releasing, unlink lockfile even if the release function throws
Consider a hypothetical bug in the release function that causes it to raise an
exception. Also consider the bisect command, which saves its state in a finally
clause. Saving the state requires acquiring the wlock.
If we don't unlink the lockfile when the exception is thrown, we'll try to
acquire the wlock again. We're going to try and acquire a lock again while our
old lockfile is on disk. The PID on disk is our own, and of course we're still
running, so we won't take over the lock. Hence we'll be stuck waiting for a
lock that we left behind ourselves.
To avoid this, always unlink the lockfile. This preserves the invariant that
self.held > 0 is equivalent to the lockfile existing on disk.
#require docutils
Test document extraction
$ HGENCODING=UTF-8
$ export HGENCODING
$ { echo C; ls "$TESTDIR/../i18n"/*.po | sort; } | while read PO; do
> LOCALE=`basename "$PO" .po`
> echo
> echo "% extracting documentation from $LOCALE"
> echo ".. -*- coding: utf-8 -*-" > gendoc-$LOCALE.txt
> echo "" >> gendoc-$LOCALE.txt
> LANGUAGE=$LOCALE python "$TESTDIR/../doc/gendoc.py" >> gendoc-$LOCALE.txt 2> /dev/null || exit
>
> if [ $LOCALE != C ]; then
> cmp -s gendoc-C.txt gendoc-$LOCALE.txt && echo '** NOTHING TRANSLATED **'
> fi
>
> # We call runrst without adding "--halt warning" to make it report
> # all errors instead of stopping on the first one.
> echo "checking for parse errors"
> python "$TESTDIR/../doc/runrst" html gendoc-$LOCALE.txt /dev/null
> done
% extracting documentation from C
checking for parse errors
% extracting documentation from da
checking for parse errors
% extracting documentation from de
checking for parse errors
% extracting documentation from el
checking for parse errors
% extracting documentation from fr
checking for parse errors
% extracting documentation from it
checking for parse errors
% extracting documentation from ja
checking for parse errors
% extracting documentation from pt_BR
checking for parse errors
% extracting documentation from ro
checking for parse errors
% extracting documentation from ru
checking for parse errors
% extracting documentation from sv
checking for parse errors
% extracting documentation from zh_CN
checking for parse errors
% extracting documentation from zh_TW
checking for parse errors