[PATCH 2 of 9 V3] localrepo: use changelog.hasnode instead of self.__contains__

[FUJIWARA Katsunori]

At Mon, 11 May 2015 18:42:46 -0700,
Pierre-Yves David wrote:
> 
> On 05/06/2015 08:15 PM, FUJIWARA Katsunori wrote:
> > # HG changeset patch
> > # User FUJIWARA Katsunori <foozy at lares.dti.ne.jp>
> > # Date 1430968030 -32400
> > #      Thu May 07 12:07:10 2015 +0900
> > # Node ID cbc75b379738476e9037b4f1adda5669963a42af
> > # Parent  449a46109f0c96bb8d82d4edf2c8855341558c2f
> > localrepo: use changelog.hasnode instead of self.__contains__
> >
> > Before this patch, releasing store lock implies actions below, when
> > 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 sotre lock:
> > resouces are acquired in "wlock => dirstateguard => store lock" order,
> > and are released in reversed order.
> >
> > This may cause that "dirstate.p1()" still refers the changeset to be
> > rollback-ed at (4) above: pushing multiple patches by "hg qpush" is
> > typical case.
> >
> > At releasing store lock, such changesets are:
> >
> >    - not contained in "repo.changelog", if it is reloaded from
> >      ".hg/00changelog.i" 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 failure.
> 
> btw, this timestamp business sounds like a bug. Do we have an issue and 
> repro for it?

Re-loading from changed (in "timestamp second" view) file itself seems
expected behavior and to work correctly.

Would you mean that there may be code paths which potentially cause
similar problem when transaction crossing the border of timestamp
second is aborted ?


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[FUJIWARA Katsunori]                             foozy at lares.dti.ne.jp