util: introduce util.debugstacktrace for showing a stack trace without crashing
This is often very handy when hacking/debugging.
Calling util.debugstacktrace('hey') from a place in hg will give something like:
hey at:
./hg:38 in <module>
/home/user/hgsrc/mercurial/dispatch.py:28 in run
/home/user/hgsrc/mercurial/dispatch.py:65 in dispatch
/home/user/hgsrc/mercurial/dispatch.py:88 in _runcatch
/home/user/hgsrc/mercurial/dispatch.py:740 in _dispatch
/home/user/hgsrc/mercurial/dispatch.py:514 in runcommand
/home/user/hgsrc/mercurial/dispatch.py:830 in _runcommand
/home/user/hgsrc/mercurial/dispatch.py:801 in checkargs
/home/user/hgsrc/mercurial/dispatch.py:737 in <lambda>
/home/user/hgsrc/mercurial/util.py:472 in check
...
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
updating to branch default
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 4 changes to 4 files
updating to branch default
4 files updated, 0 files merged, 0 files removed, 0 files unresolved