Mercurial > hg
view tests/test-rebase-interruptions.t @ 14007:d764463b433e
atomictempfile: avoid infinite recursion in __del__().
The problem is that a programmer using atomictempfile directly can
make an innocent everyday mistake -- not enough args to the
constructor -- which escalates badly. You would expect a simple
TypeError crash in that case, but you actually get an infinite
recursion that is surprisingly difficult to kill: it happens between
__del__() and __getattr__(), and Python does not handle infinite
recursion from __del__() well.
The fix is to not implement __getattr__(), but instead assign instance
attributes for the methods we wish to delegate to the builtin file
type: write() and fileno(). I've audited mercurial.* and hgext.* and
found no users of atomictempfile using methods other than write() and
rename(). I audited third-party extensions and found one (snap)
passing an atomictempfile to util.fstat(), so I also threw in
fileno().
The last time I submitted a similar patch, Matt proposed that we make
atomictempfile a subclass of file instead of wrapping it. Rejected on
grounds of unnecessary complexity: for one thing, it would make the
Windows implementation of posixfile quite a bit more complex. It would
have to become a subclass of file rather than a simple function -- but
since it's written in C, this is non-obvious and non-trivial.
Furthermore, there's nothing wrong with wrapping objects and
delegating methods: it's a well-established pattern that works just
fine in many cases. Subclassing is not the answer to all of life's
problems.
author | Greg Ward <greg@gerg.ca> |
---|---|
date | Sun, 24 Apr 2011 19:25:10 -0400 |
parents | b19b4c1df066 |
children | 2371f4aea665 |
line wrap: on
line source
$ cat >> $HGRCPATH <<EOF > [extensions] > graphlog= > rebase= > > [alias] > tglog = log -G --template "{rev}: '{desc}' {branches}\n" > EOF $ hg init a $ cd a $ echo A > A $ hg ci -Am A adding A $ echo B > B $ hg ci -Am B adding B $ echo C >> A $ hg ci -m C $ hg up -q -C 0 $ echo D >> A $ hg ci -m D created new head $ echo E > E $ hg ci -Am E adding E $ cd .. Changes during an interruption - continue: $ hg clone -q -u . a a1 $ cd a1 $ hg tglog @ 4: 'E' | o 3: 'D' | | o 2: 'C' | | | o 1: 'B' |/ o 0: 'A' Rebasing B onto E: $ hg rebase -s 1 -d 4 merging A warning: conflicts during merge. merging A failed! abort: unresolved conflicts (see hg resolve, then hg rebase --continue) [255] Force a commit on C during the interruption: $ hg up -q -C 2 $ echo 'Extra' > Extra $ hg add Extra $ hg ci -m 'Extra' $ hg tglog @ 6: 'Extra' | | o 5: 'B' | | | o 4: 'E' | | | o 3: 'D' | | o | 2: 'C' | | o | 1: 'B' |/ o 0: 'A' Resume the rebasing: $ hg rebase --continue merging A warning: conflicts during merge. merging A failed! abort: unresolved conflicts (see hg resolve, then hg rebase --continue) [255] Solve the conflict and go on: $ echo 'conflict solved' > A $ rm A.orig $ hg resolve -m A $ hg rebase --continue warning: new changesets detected on source branch, not stripping $ hg tglog @ 7: 'C' | | o 6: 'Extra' | | o | 5: 'B' | | o | 4: 'E' | | o | 3: 'D' | | | o 2: 'C' | | | o 1: 'B' |/ o 0: 'A' $ cd .. Changes during an interruption - abort: $ hg clone -q -u . a a2 $ cd a2 $ hg tglog @ 4: 'E' | o 3: 'D' | | o 2: 'C' | | | o 1: 'B' |/ o 0: 'A' Rebasing B onto E: $ hg rebase -s 1 -d 4 merging A warning: conflicts during merge. merging A failed! abort: unresolved conflicts (see hg resolve, then hg rebase --continue) [255] Force a commit on B' during the interruption: $ hg up -q -C 5 $ echo 'Extra' > Extra $ hg add Extra $ hg ci -m 'Extra' $ hg tglog @ 6: 'Extra' | o 5: 'B' | o 4: 'E' | o 3: 'D' | | o 2: 'C' | | | o 1: 'B' |/ o 0: 'A' Abort the rebasing: $ hg rebase --abort warning: new changesets detected on target branch, can't abort [255] $ hg tglog @ 6: 'Extra' | o 5: 'B' | o 4: 'E' | o 3: 'D' | | o 2: 'C' | | | o 1: 'B' |/ o 0: 'A' $ cd ..