check-config: use raw strings for regular expressions This avoids SyntaxWarning on Python 3.8 for invalid \ escapes. Differential Revision: https://phab.mercurial-scm.org/D5826

run-tests: use raw strings for regular expressions Avoids SyntaxWarning due to invalid \ escape on Python 3.8. Differential Revision: https://phab.mercurial-scm.org/D5825

check-commit: use raw string for regular expression Avoids SyntaxWarning on Python 3.8. Differential Revision: https://phab.mercurial-scm.org/D5824

configitems: use raw strings for hidden-{command,topic} items These strings are regular expressions. The "\." needs to be string escaped. We use raw strings to avoid doing that and the SyntaxWarning we'd receive otherwise on Python 3.8. Differential Revision: https://phab.mercurial-scm.org/D5822

convert: use raw string for regular expressions This avoids a SyntaxWarning on Python 3.8. Differential Revision: https://phab.mercurial-scm.org/D5821

graphmod: use raw string Needed to avoid a SyntaxWarning due to unescaped \ in Python 3.8. Differential Revision: https://phab.mercurial-scm.org/D5820

crecord: use raw string for regular expression \s emits a SyntaxWarning in Python 3.8. Use a raw string to avoid escaping the \. Differential Revision: https://phab.mercurial-scm.org/D5819

patch: properly escape \ in string literals Python 3.8 will emit a SyntaxWarning for str/bytes with invalid escapes. This commit addresses 4 occurrences where we had a bare \ in a str/bytes. Differential Revision: https://phab.mercurial-scm.org/D5818

global: make some docstrings raw strings Python 3.8 emits a SyntaxWarning when a str/bytes contains invalid \ escapes. Various docstrings in our code base contain invalid \ escapes. This commit turns those docstrings into raw strings. Differential Revision: https://phab.mercurial-scm.org/D5816

global: use raw strings for regular expressions with escapes Escape sequences like \w, \s, and \d are technically invalid in str/bytes. This became a deprecation warning in Python 3.6 (https://bugs.python.org/issue27364). Python 3.8 bumps it to a SyntaxWarning (https://bugs.python.org/issue32912), which is non-silent by default. This commit changes a number of regular expressions to use br'' so regular expression special sequences don't need \\ literals. This fixes roughly half of the SyntaxWarning we see in the code base with Python 3.8. Differential Revision: https://phab.mercurial-scm.org/D5815

tests: add optional Python 2.7 deprecation output pip 19 will emit a Python 2.7 deprecation warning when used with Python 2.7. Let's add that as optional output to our pip test. Differential Revision: https://phab.mercurial-scm.org/D5823

tests: fix test-match.py on Python3 # skip-blame just b prefixes Differential Revision: https://phab.mercurial-scm.org/D5835

merge with stable

match: teach diffmatcher.visitdir() to return 'all' if possible This patch teaches differencematcher.visitdir() to return 'all' when m1.visitdir() returns 'all' and m2 does not matches. Before this patch, from a differencematcher.visitdir(), we always returned either True or False. We never returned 'all' even when we can. This causes problem when m1 and m2 of a differencematcher are themselves differencematcher. In that case, we try to check: `if self._m2_.visitdir(dir) == 'all'` which will never be 'all' even though it can be. This leads to iterating over a lot of sub-directory manifest, even though we don't want to while extending a narrow clone. I am yet to measure the impact of this but calculating manifest was taking ~50-60 seconds, so this should definitely save some of time there. Differential Revision: https://phab.mercurial-scm.org/D5814