py3: use sysstr() to convert ProgrammingError bytes with no unicode error risk msg.decode('utf8') may fail if msg isn't an ASCII string, and that's possible as we sometimes embed a filename in the error message for example.

revlog: reuse cached delta for identical base revision (issue5975) Since 8f83a953dddf, we skip over empty deltas when choosing a delta base. Such delta happens when two distinct revisions have the same content. The remote might be sending a delta against such revision within the bundle. In that case, the delta base is no longer considered, but the cached one could still, be used with the equivalent revision. Not reusing the delta from the bundle can have a significant performance impact, so we now make sure with doing so when possible.

snapshot: fix line order when skipping over empty deltas The code movement in 37957e07138c introduced an error. Since 8f83a953dddf, we discarded some revisions because they are identical to their delta base (and use that delta base instead). That logic is good, however, in 37957e07138c we mixed up the order of two line, adding the "new" revision to the set of already tested one, instead of the discarded one. So in practice, we were never investigating any revisions in a chain starting with an empty delta. Creating significantly worst delta chain (eg: Mercurial's manifest move goes from about 60MB up to about 80MB).

tests: stabilize change for handling not quoting non-empty-directory The change originated in cb1329738d64. I suspect the problem is with the combination of (re) and the '\' to '/' retry on Windows. I've no idea if py3 on Windows needs the quoting, since it can't even run `hg` with no arguments. (It's dying somewhere on the ctype declarations when win32.py is imported.)

hg: wrap the highest layer in the `hg` script possible in trace event This should help us have a better idea of what "interpreter startup costs" look like. This does omit the HGUNICODEPEDANTRY block and the LIBDIR dancing to set up sys.path, but the former is usually off and the latter is unavoidable and should be very fast. If we get worried about those cases we can consider open-coding the tracing logic here. Differential Revision: https://phab.mercurial-scm.org/D4346

localrepo: use urllocalpath() for path to create repo too It looks like this was lost in 7ce9dea3a14a (localrepo: move repo creation logic out of localrepository.__init__ (API), 2018-09-11). I don't know when it makes a difference (maybe on Windows, since urllocalpath() mentions something about drive letters). Differential Revision: https://phab.mercurial-scm.org/D4550

localrepo: move check for existing repo into createrepository() For symmetry with the check for existence of a repo in localrepository.__init__, we should check for the non-existence in createrepository(). We could alternatively move both checks into instance(). Differential Revision: https://phab.mercurial-scm.org/D4549

py3: add b'' to some run-tests.py strings for Windows Things go seriously off the rails after this, so there may be more that are missing. # skip-blame since these are just converting to bytes literals

wireprotov1peer: forward __name__ of wrapped method in batchable decorator Not required, but clarifies debugging when the going gets really tough. Differential Revision: https://phab.mercurial-scm.org/D4551

templatekw: add {size} keyword as an example of fctx-based keyword I'll add {status}, and I think some lfs keywords can be migrated to this. I'm not certain how many fctx-based keywords will be introduced into the global space, but if there are a couple more, we'll probably need to sort them out to the "File Keywords" section in the templater help. Until then, fctx keywords are hidden as experimental.