flagprocessor: add a fast path when flags is 0 When flags is 0, _processflags could be a no-op instead of iterating through the flag bits.

shelve: make shelvestate use simplekeyvaluefile Currently shelvestate uses line ordering to differentiate fields. This makes it hard for extensions to wrap shelve, since if two alternative versions of code add a new line, correct merging is going to be problematic. simplekeyvaluefile was introduced fot this purpose specifically. After this patch: - shelve will always write a simplekeyvaluefile - unshelve will check the first line of the file for a version, and if the version is 1, will read it in a position-based way, if the version is 2, will read it in a key-value way As discussed with Yuya previously, this will be able to handle old-style shelvedstate files, but old Mercurial versions will fail on the attempt to read shelvedstate file of version 2 with a self-explanatory message: 'abort: this version of shelve is incompatible with the version used in this repo'

shelve: refactor shelvestate loading This is a preparatory patch which separates file reading from the minimal validation we have (like turning version into int and checking that this version is supported). The purpose of this patch is to be able to read statefile form simplekeyvaluefile, which is implemented in the following patch.

extdiff: copy back execbit-only changes to the working directory Some tools like BeyondCompare allow the file mode to be changed. The change was previously applied if the content of the file changed (either according to size or mtime), but was not being copied back for a mode-only change. That would seem to indicate handling this in an 'elif' branch, but I opted not to in order to avoid copying back the mode without the content changes when mtime and size are unchanged. (Yes, that's a rare corner case, but all the more reason not to have a subtle difference in behavior.) The only way I can think to handle this undetected change is to set each file in the non-wdir() snapshot to readonly, and check for that attribute (as well as mtime) when deciding to copy back. That would avoid the overhead of copying the whole file when only the mode changed. But a chmod in a diff tool is likely rare. See also affd753ddaf1.

tests: remove regular expression matching for Python 2.6 This effectively reverts 52cca17ac523. Some lines still have (re) due to variable length port numbers. There's not much we can do about that. But at least this change removes most of the ugliness.

branchmap: remove use of buffer() to support Python 2.6 The use of buffer() was added in 7359157b9e46 to support Python 2.6, which we no longer support.

py3: remove delayed import of importlib All supported versions of Python now have importlib. This effectively reverts b85fa6bf298b.

tests: use context manager form of assertRaises Support for using unittest.TestCase.assertRaises as a context manager was added in Python 2.7. This form is more readable, especially for complex tests. While I was here, I also restored the use of assertRaisesRegexp, which was removed in c6921568cd20 for Python 2.6 compatibility.

obsolete: use 2 argument form of enumerate() The 2 argument form of enumerate was added in Python 2.6. This change effectively reverts 10880c8aad85.

tests: remove special handling for undefined memoryview 'memoryview' was introduced in Python 2.7. 4adc090fa2fb added code to filterpyflakes.py to ignore "undefined name 'memoryview'" pyflakes warnings. Since we no longer support <Python 2.7, we can remove this workaround.