policy: add "cext" package which will host CPython extension modules I'm going to restructure cext/pure modules and get rid of our hgimporter hack. C extension modules will be moved to cext/ directory so old and new compiled modules can coexist in development tree. This is necessary to run 'hg bisect' without recompiling. New extension modules will be loaded by an importer function: base85 = policy.importmod('base85') # select pure.base85 or cext.base85 This will also allow us to split cffi from pure modules, which is currently difficult because pure modules can't be imported by name.

policy: mark all string literals as sysstr or bytes The policy module won't be imported early in future, which means string literals will be processed by our Python 3 loader.

debuginstall: check C extensions only if they are loadable per policy This check is useless in pure installation and I want to make it directly import C extension modules.

osutil: proxy through util (and platform) modules (API) See the previous commit for why. Marked as API change since osutil.listdir() seems widely used in third-party extensions. The win32mbcs extension is updated to wrap both util. and windows. aliases.

win32mbcs: wrap underlying pycompat.bytestr to use checkwinfilename safely win32mbcs wraps some functions, to prevent them from unintentionally treating backslash (0x5c), which is used as the second or later byte of multi bytes characters by problematic encodings, as a path component delimiter on Windows platform. This wrapping assumes that wrapped functions can safely accept unicode string arguments. Unfortunately, d1937bdcee8c broke this assumption by introducing pycompat.bytestr() into util.checkwinfilename() for py3 support. After that, wrapped checkwinfilename() always fails for non-ASCII filename at pycompat.bytestr() invocation. This patch wraps underlying pycompat.bytestr() function to use util.checkwinfilename() safely. To avoid similar regression in the future, another patch series will add smoke testing on default branch.

hghave: prefill more version of Mercurial The previous code was unable to go above version 4.0.

graft: fix graft across merges of duplicates of grafted changes Graft used findmissingrevs to find the candidates for graft duplicates in the destination. That function operates with the constraint: 1. N is an ancestor of some node in 'heads' 2. N is not an ancestor of any node in 'common' For our purpose, we do however have to work correctly in cases where the graft set has multiple roots or where merges between graft ranges are skipped. The only changesets we can be sure doesn't have ancestors that are grafts of any changeset in the graftset, are the ones that are common ancestors of *all* changesets in the graftset. We thus need: 2. N is not an ancestor of all nodes in 'common' This change will graft more correctly, but it will also in some cases make graft slower by making it search through a bigger and unnecessary large sets of changes to find duplicates. In the general case of grafting individual or linear sets, we do the same amount of work as before.

graft: test coverage of grafts and how merges can break duplicate detection This demonstrates unfortunate behaviour: extending the graft range cause the graft to behave differently. When the graft range includes a merge, we fail to detect duplicates that are ancestors of the merge.

mpatch: proxy through mdiff module See the previous commit for why.

bdiff: proxy through mdiff module See the previous commit for why. mdiff seems a good place to host bdiff functions. bdiff.bdiff was already aliased as textdiff, so we use it.

base85: proxy through util module I'm going to replace hgimporter with a simpler import function, so we can access to pure/cext modules by name: # util.py base85 = policy.importmod('base85') # select pure.base85 or cext.base85 # cffi/base85.py from ..pure.base85 import * # may re-export pure.base85 functions This means we'll have to use policy.importmod() function in place of the standard import statement, but we wouldn't want to write it every place where C extension modules are used. So this patch makes util host base85 functions.

mdiff: move re-exports to top This style seems more common in our codebase.

test-commit-interactive-curses: remove unused import of parsers

churn: use the non-deprecated template option in the examples

strip: make tree stripping O(changes) instead of O(repo) The old tree stripping logic iterated over every tree revlog in the repo looking for commits that had revs to be stripped. That's very inefficient in large repos. Instead, let's look at what files are touched by the strip and only inspect those revlogs. I don't have actual perf numbers, since internally we don't use a true treemanifest, but simply iterating over hundreds of thousands of revlogs takes many, many seconds, so this should help tremendously when stripping only a few commits.

strip: move tree strip logic to it's own function This will allow external extensions to modify tree strip behavior more precisely.

manifest: remove unused property _oldmanifest The last use seems to have gone away in 7c7d845f8b64 (manifest: make manifestlog use it's own cache, 2016-11-10).

sslutil: reference fingerprints config option properly (issue5559) The config option is "host:fingerprints" not "host.fingerprints". This warning message is bad and misleads users.

py3: convert key to str to make kwargs.pop work in mq The keys are passed here and there as unicodes and our transformer make things bytes. Due to that, mq was not poped and this results in error on Py3. Here we abuse r'' to make that str on Python 3.

py3: convert kwargs' keys to str before passing in cmdutil.getcommiteditor

diff: add a fast path to avoid loading binary contents When diffing binary contents, with certain configs, we can show "Binary file <name> has changed" without actual content. That allows a fast path where we could avoid providing actual binary contents. Note: in that case we still need to test if two contents are the same, that's done by using "filectx.cmp", which could have its own fast path.

diff: correct binary testing logic This seems to be more correct given the table drawn in the previous patch. Namely, "losedatafn" and "opts.git" are removed, "not opts.text" is added. - losedatafn: diff output (binary) should not be affected by "losedatafn" - opts.git: binary testing is helpful for detecting a fast path in the next path. the fast path can also be used if opts.git is False - opts.text: if it's set, we should treat the content as non-binary

diff: draw a table about binary diff behaviors The table should make it easier to reason about future changes.

diff: use fctx.size() to test empty fctx.size() could have a fast path that does not require loading content.

diff: use fctx.isbinary() to test binary The end goal is to avoid calling fctx.data() when unnecessary. For example, if diff.nobinary=1 and files are binary, the expected behavior is to print "Binary file has changed". That could avoid reading fctx.data() sometimes. This is mainly to enable an external LFS extension to skip expensive binary file loading sometimes (read: most of the time with diff.nobinary=1 and diff.text=0), without any behavior changes to mercurial (i.e. whether a file is LFS or not does not change any behavior, LFS could be 100% transparent to users).

pycompat: extract helper to raise exception with traceback It uses "raise excobj, None, tb" form which I think is simpler and more useful than "raise exctype, args, tb".

largefiles: make sure debugstate command is populated before wrapping Copied the hack from 869d660b8669, which seemed the simplest workaround. Perhaps debugcommands.py should have its own commands table.

check-code: ignore re-exports of os.environ in encoding.py These are valid uses of os.environ.

check-code: exclude demandimport.py and policy.py from Python 3 checks These modules can't depend on pycompat.py, which means we have to write Py3 hacks in them.

check-code: rewrite py3 exclusion pattern with negative lookahead I want to add more patterns, but negative lookbehind requires patterns of the same length so not useful.