changeset 24992:7df090c9c9fe

localrepo: use changelog.hasnode instead of self.__contains__

Before this patch, releasing the store lock implies the actions below, when
the transaction is aborted:

  1. "commithook()" scheduled in "localrepository.commit()" is invoked
  2. "changectx.__init__()" is invoked via "self.__contains__()"
  3. specified ID is examined against "repo.dirstate.p1()"
  4. validation function is invoked in "dirstate.p1()"

In subsequent patches, "dirstate.invalidate()" invocations for
discarding changes are replaced with "dirstateguard", but discarding
changes by "dirstateguard" is executed after releasing the store lock:
resources are acquired in "wlock => dirstateguard => store lock" order,
and are released in reverse order.

This may cause that "dirstate.p1()" still refers to the changeset to be
rolled-back at (4) above: pushing multiple patches by "hg qpush" is
a typical case.

When releasing the store lock, such changesets are:

  - not contained in "repo.changelog", if it is reloaded from
    ".hg/00changelog.i", as that file was already truncated by
    "transaction.abort()"

  - still contained in it, otherwise
    (this "dirty read" problem is discussed in "Transaction Plan"
     http://mercurial.selenic.com/wiki/TransactionPlan)

Validation function shows "unknown working parent" warning in the
former case, but reloading "repo.changelog" depends on the timestamp
of ".hg/00changelog.i". This causes occasional test failures.

In the case of scheduled "commithook()", it just wants to examine
whether "node ID" of committed changeset is still valid or not. Other
examinations implied in "changectx.__init__()" are meaningless.

To avoid showing the "unknown working parent" warning irregularly, this
patch uses "changelog.hasnode()" instead of "node in self" to examine
existence of committed changeset.

--- a/mercurial/localrepo.py	Thu May 07 12:07:10 2015 +0900
+++ b/mercurial/localrepo.py	Thu May 07 12:07:10 2015 +0900
@@ -1517,7 +1517,7 @@
         def commithook(node=hex(ret), parent1=hookp1, parent2=hookp2):
             # hack for command that use a temporary commit (eg: histedit)
             # temporary commit got stripped before hook release
-            if node in self:
+            if self.changelog.hasnode(ret):
                 self.hook("commit", node=node, parent1=parent1,
                           parent2=parent2)
         self._afterlock(commithook)

--- a/tests/test-mq-qpush-fail.t	Thu May 07 12:07:10 2015 +0900
+++ b/tests/test-mq-qpush-fail.t	Thu May 07 12:07:10 2015 +0900
@@ -34,7 +34,23 @@
   $ $PYTHON -c 'print "\xe9"' > message
   $ cat .hg/patches/bad-patch >> message
   $ mv message .hg/patches/bad-patch
-  $ hg qpush -a && echo 'qpush succeeded?!'
+  $ cat > $TESTTMP/wrapplayback.py <<EOF
+  > import os
+  > from mercurial import extensions, transaction
+  > def wrapplayback(orig,
+  >                  journal, report, opener, vfsmap, entries, backupentries,
+  >                  unlink=True):
+  >     orig(journal, report, opener, vfsmap, entries, backupentries, unlink)
+  >     # Touching files truncated at "transaction.abort" causes
+  >     # forcible re-loading invalidated filecache properties
+  >     # (including repo.changelog)
+  >     for f, o, _ignore in entries:
+  >         if o or not unlink:
+  >             os.utime(opener.join(f), (0.0, 0.0))
+  > def extsetup(ui):
+  >     extensions.wrapfunction(transaction, '_playback', wrapplayback)
+  > EOF
+  $ hg qpush -a --config extensions.wrapplayback=$TESTTMP/wrapplayback.py  && echo 'qpush succeeded?!'
   applying patch1
   applying patch2
   applying bad-patch