Mercurial > hg
view tests/test-mq-qimport-fail-cleanup.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 | 8b12768b15e2 |
children | 1e9451476bf8 |
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Failed qimport of patches from files should cleanup by recording successfully imported patches in series file. $ echo "[extensions]" >> $HGRCPATH $ echo "mq=" >> $HGRCPATH $ hg init repo $ cd repo $ echo a > a $ hg ci -Am'add a' adding a $ cat >b.patch<<EOF > diff --git a/a b/a > --- a/a > +++ b/a > @@ -1,1 +1,2 @@ > a > +b > EOF $ echo empty series $ hg qseries $ echo qimport valid patch followed by invalid patch $ hg qimport b.patch fakepatch adding b.patch to series file abort: unable to read file fakepatch [255] $ echo valid patches before fail added to series $ hg qseries b.patch