reachableroots: unify bail cases to raise exception correctly Before this patch, release_seen_and_tovisit did not return NULL, so the exception was not raised immediately. As Py_XDECREF() and free() are safe for NULL, we can simply bail in any case.

reachableroots: pass NULL to PySet_New() as it expects a pointer, not an int

merge with stable

copy: add flag for disabling copy tracing Copy tracing can be up to 80% of rebase time when rebasing stacks of commits in large repos (hundreds of thousands of files). This provides the option of turning off the majority of copy tracing. It does not turn off _forwardcopies() since that is used to carry copy information inside a commit across a rebase. This will affect the situation where a user edits a file, then rebases on top of commits that have moved that file. The move will not be detected and the user will have to manually resolve the issue (possibly by redoing the rebase with this flag off). The reason to have a flag instead of trying to fix the actual copy tracing performance is that copy tracing is fundamentally an O(number of files in the repo) operation. In order to know if file X in the rebase source was copied anywhere, we have to walk the filelog for every new file that exists in the rebase destination (i.e. a file in the destination that is not in the common ancestor). Without an index that lets us trace forward (i.e. from file Y in the common ancestor forward to the rebase destination), it will never be an O(number of changes in my branch) operation. In mozilla-central, rebasing a 3 commit stack across 20,000 revs goes from 39s to 11s.

strip: use the 'finally: tr.release' pattern during stripping The previous code, was calling 'abort' in all exception cases. This was wrong when an exception was raised by post-close callback on the transaction. Calling 'abort' on an already closed transaction resulted in a error, shadowing the original error. We now use the same pattern as everywhere else. 'tr.release()' will abort the transaction if we escape the scope without closing it. We add a test to make sure we do not regress.

changelog: trust C implementation of reachableroots more There are no remaining codepaths in reachableroots where it will return None, so just trust it completely and simplify this method. Result by revset ================ Revision: 0) Revision 1c75249e159b: style: adjust whitespaces in webutil.py 1) Revision d1d91b8090c6: changelog: trust C implementation of reachableroots more revset #0: 0::tip plain 0) 0.067684 1) 0.006622 9% revset #1: 0::@ plain 0) 0.068249 1) 0.009394 13% IOW this is a 10x speedup in my repo for hg itself for 0::tip and similar revsets now that the C code is correctly wired up.

reachableroots: return NULL if we're throwing an exception Based on my reading of [0] and surrounding sections, if we want an exception to be properly raised when something goes wrong in the C code, we need to make sure we return NULL here. Do so. https://docs.python.org/2/extending/extending.html#back-to-the-example

reachableroots: fix transposition of set and list types in PyArg_ParseTuple This is being masked by the function not properly returning NULL when it raises an exception, so the client code was just falling back to the native codepath when it got None back. A future change removes all reason for this C function to return None, which exposed this problem during development.