tests: check importing modules in perf.py for historical portability To check importing modules in perf.py for historical portability, this patch lists up files by "hg files" both for "1.2" and tip, and builds up "module whitelist" check from those files. This patch uses "1.2" as earlier side version of "module whitelist", because "mercurial.error" module is a blocker for loading perf.py with Mercurial earlier than 1.2, and just importing "mercurial.error" separately isn't enough.

tests: introduce check-perf-code.py to add extra checks on perf.py This patch introduces tests/check-perf-code.py as a preparation for adding extra checks on contrib/perf.py in subsequent patches (mainly, for historical portability). At this change, check-perf-code.py doesn't add any extra check, and is equal to check-code.py. This makes subsequent patch focus only on adding an extra check on perf.py check-perf-code.py. check-perf-code.py adds extra checks on perf.py by wrapping contrib/check-code.py, because "filtering" by check-code.py (e.g. normalize characters in string literal or comment line) is useful to simplify regexp for check, and avoid false positive matching.

check-code: move fixing up regexp into main procedure This patch makes an extra check pattern to be prepared by "_preparepats()" as similarly as existing patterns, if it is added to "checks" array before invocation of "main()" in check-code.py. This is a part of preparation for adding check-code.py extra checks by another python script in subsequent patch. This is also useful for SkeletonExtensionPlan. https://www.mercurial-scm.org/wiki/SkeletonExtensionPlan

check-code: factor out boot procedure into main This is a part of preparation for adding check-code.py extra checks by another python script in subsequent patch. This is also useful for SkeletonExtensionPlan. https://www.mercurial-scm.org/wiki/SkeletonExtensionPlan

perf: import newer modules separately for earlier Mercurial demandimport of early Mercurial loads an imported module immediately, if a module is imported absolutely by "from a import b" style. Recent perf.py satisfies this condition, because it does: - have "from __future__ import absolute_import" line - use "from a import b" style for modules in "mercurial" package Before this patch, importing modules below prevents perf.py from being loaded by earlier Mercurial, because these aren't available in such Mercurial, even though there are some code paths for Mercurial earlier than 1.9. - branchmap 2.5 (or bcee63733aad) - repoview 2.5 (or 3a6ddacb7198) - obsolete 2.3 (or ad0d6c2b3279) - scmutil 1.9 (or 8b252e826c68) For example, setting "_prereadsize" attribute in perfindex() and perfnodelookup() is effective only with Mercurial earlier than 1.8 (or 61c9bc3da402). After this patch, "mercurial.error" is the only blocker in "from mercurial import" statement for loading perf.py with Mercurial earlier than 1.2. This patch ignores it, because just importing it separately isn't enough.

py3: conditionalize BaseHTTPServer, SimpleHTTPServer and CGIHTTPServer import The BaseHTTPServer, SimpleHTTPServer and CGIHTTPServer has been merged into http.server in python 3. All of them has been merged as util.httpserver to use in both python 2 and 3. This patch adds a regex to check-code to warn against the use of BaseHTTPServer. Moreover this patch also includes updates to lower part of test-check-py3-compat.t which used to remain unchanged.

py3: re-implement the BaseHTTPServer.test() function The function is changed in python 3. So the latest version of function is re-implemented. One can look at https://hg.python.org/cpython/file/3.5/Lib/http/server.py#l1184 and https://hg.python.org/cpython/file/2.7/Lib/BaseHTTPServer.py#l590 to see the change