Mercurial > hg
view tests/test-convert-hg-sink.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 | 81bf25ddd76a |
children | 77872b002e73 |
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$ cat >> $HGRCPATH <<EOF > [extensions] > convert= > [convert] > hg.saverev=False > EOF $ hg init orig $ cd orig $ echo foo > foo $ echo bar > bar $ hg ci -qAm 'add foo and bar' $ hg rm foo $ hg ci -m 'remove foo' $ mkdir foo $ echo file > foo/file $ hg ci -qAm 'add foo/file' $ hg tag some-tag $ hg log changeset: 3:593cbf6fb2b4 tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: Added tag some-tag for changeset ad681a868e44 changeset: 2:ad681a868e44 tag: some-tag user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add foo/file changeset: 1:cbba8ecc03b7 user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: remove foo changeset: 0:327daa9251fa user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: add foo and bar $ cd .. $ hg convert orig new 2>&1 | grep -v 'subversion python bindings could not be loaded' initializing destination new repository scanning source... sorting... converting... 3 add foo and bar 2 remove foo 1 add foo/file 0 Added tag some-tag for changeset ad681a868e44 $ cd new $ hg out ../orig comparing with ../orig searching for changes no changes found [1] dirstate should be empty: $ hg debugstate $ hg parents -q $ hg up -C 3 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg copy bar baz put something in the dirstate: $ hg debugstate > debugstate $ grep baz debugstate a 0 -1 unset baz copy: bar -> baz add a new revision in the original repo $ cd ../orig $ echo baz > baz $ hg ci -qAm 'add baz' $ cd .. $ hg convert orig new 2>&1 | grep -v 'subversion python bindings could not be loaded' scanning source... sorting... converting... 0 add baz $ cd new $ hg out ../orig comparing with ../orig searching for changes no changes found [1] dirstate should be the same (no output below): $ hg debugstate > new-debugstate $ diff debugstate new-debugstate no copies $ hg up -C 1 files updated, 0 files merged, 0 files removed, 0 files unresolved $ hg debugrename baz baz not renamed $ cd .. test tag rewriting $ cat > filemap <<EOF > exclude foo > EOF $ hg convert --filemap filemap orig new-filemap 2>&1 | grep -v 'subversion python bindings could not be loaded' initializing destination new-filemap repository scanning source... sorting... converting... 4 add foo and bar 3 remove foo 2 add foo/file 1 Added tag some-tag for changeset ad681a868e44 0 add baz $ cd new-filemap $ hg tags tip 2:6f4fd1df87fb some-tag 0:ba8636729451 $ cd ..