annotate 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.

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