py3: have bytes version of sys.argv sys.argv returns unicodes on Python 3. We need a bytes version for us. There was also a python bug/feature request which wanted then to implement one. They rejected and it is quoted in one of the comments that we can use fsencode() to get a bytes version of sys.argv. Though not sure about its correctness. Link to the comment: http://bugs.python.org/issue8776#msg217416 After this patch we will have pycompat.sysargv which will return us bytes version of sys.argv. If this patch goes in, i will like to make transformer rewrite sys.argv with pycompat.argv because there are lot of occurences.

util: use '\\' rather than using r'\' We need bytes, and I find this just a little more immediately obvious than doing rb'\'.

util: use pycompat urlunquote function

pycompat: introduce an alias for urllib.unquote We have to use unquote_to_bytes on Python 3, so we need an abstraction for this.

keyword: handle filectx _customcmp Suggested by Yuya Nishihara: https://www.mercurial-scm.org/pipermail/mercurial-devel/2016-October/089461.html Related to issue5364.

mail: do not print(), use ui.debug() instead Since print() can't take a bytes output, it's pretty useless in Mercurial on Python 3. As this is a debug message, switching to ui.debug() seems fine.

progress: obtain stderr from ui This will help Python 3 porting.

simplemerge: obtain stdout from ui This will help Python 3 porting.

profiling: obtain stderr from ui This will help Python 3 porting.

scmutil: ignore EPERM at os.utime, which avoids ambiguity at closing According to POSIX specification, just having group write access to a file causes EPERM at invocation of os.utime() with an explicit time information (e.g. working on the repository shared by group access permission). To ignore EPERM at closing file object in such case, this patch makes checkambigatclosing._checkambig() use filestat.avoidambig() introduced by previous patch. Some functions below imply this code path at truncation of an existing (= might be owned by another user) file. - strip() in repair.py, introduced by e38d85be978f - _playback() in transaction.py, introduced by 599912a62ff6 This is a variant of issue5418.

vfs: ignore EPERM at os.utime, which avoids ambiguity at renaming (issue5418) According to POSIX specification, just having group write access to a file causes EPERM at invocation of os.utime() with an explicit time information (e.g. working on the repository shared by group access permission). To ignore EPERM at renaming in such case, this patch makes vfs.rename() use filestat.avoidambig() introduced by previous patch.

util: add utility function to skip avoiding file stat ambiguity if EPERM Now, advancing stat.st_mtime by os.utime() is used to avoid file stat ambiguity. But according to POSIX specification, utime(2) with an explicit time information is permitted only for a process with: - the effective user ID equal to the user ID of the file, or - appropriate privileges http://pubs.opengroup.org/onlinepubs/9699919799/functions/utime.html Therefore, just having group write access to a file causes EPERM at applying os.utime() on it (e.g. working on the repository shared by group access permission). This patch adds class filestat utility function avoidamgig() to avoid file stat ambiguity but skip it if EPERM. It is reasonable to always ignore EPERM, because utime(2) causes EPERM only in the case described above (EACCES is used only for utime(2) with NULL).

bdiff: replace hash algorithm This patch replaces lyhash with the hash algorithm used by diffutils. The algorithm has its origins in Git commit 2e9d1410, which is all the way back from 1992. The license header in the code at that revision in GPL v2. I have not performed an extensive analysis of the distribution (and therefore buckets) of hash output. However, `hg perfbdiff` gives some clear wins. I'd like to think that if it is good enough for diffutils it is good enough for us? From the mozilla-unified repository: $ perfbdiff -m 3041e4d59df2 ! wall 0.053271 comb 0.060000 user 0.060000 sys 0.000000 (best of 100) ! wall 0.035827 comb 0.040000 user 0.040000 sys 0.000000 (best of 100) $ perfbdiff 0e9928989e9c --alldata --count 100 ! wall 6.204277 comb 6.200000 user 6.200000 sys 0.000000 (best of 3) ! wall 4.309710 comb 4.300000 user 4.300000 sys 0.000000 (best of 3) From the hg repo: $ perfbdiff 35000 --alldata --count 1000 ! wall 0.660358 comb 0.660000 user 0.660000 sys 0.000000 (best of 15) ! wall 0.534092 comb 0.530000 user 0.530000 sys 0.000000 (best of 19) Looking at the generated assembly and statistical profiler output from the kernel level, I believe there is room to make this function even faster. Namely, we're still consuming data character by character instead of at the word level. This translates to more loop iterations and more instructions. At this juncture though, the real performance killer is that we're hashing every line. We should get a significant speedup if we change the algorithm to find the longest prefix, longest suffix, treat those as single "lines" and then only do the line splitting and hashing on the parts that are different. That will require a lot of C code, however. I'm optimistic this approach could result in a ~2x speedup.

profiling: make statprof the default profiler (BC) The statprof sampling profiler runs with significantly less overhead. Its data is therefore more useful. Furthermore, its default output shows the hotpath by default, which I've found to be way more useful than the default profiler's function time table. There is one behavioral regression with this change worth noting: the statprof profiler currently doesn't profile individual hgweb requests like lsprof does. This is because the current implementation of statprof only profiles the thread that started profiling. The ability for lsprof to profile individual hgweb requests is relatively new and likely not widely used. Furthermore, I have plans to modify statprof to support profiling multiple threads. I expect that change to go through several iterations. I'm submitting this patch first so there is more time to test statprof. Perfect is the enemy of good.

profiling: use vendored statprof and upstream enhancements (BC) Now that the statprof module is vendored and suitable for use, we switch our statprof profiler to use it. This required some minor changes because of drift between the official statprof profiler and the vendored copy. We also incorporate Facebook's improvements from the "statprofext" extension at https://bitbucket.org/facebook/hg-experimental, notably support for different display formats. Because statprof output is different, this is marked as BC. Although most users likely won't notice since most users don't profile.

crecord: use scmutil.termsize()

scmutil: extend termwidth() to return terminal height, renamed to termsize() It appears crecord.py has its own termsize() function. I want to get rid of it. The fallback height is chosen from the default of cmd.exe on Windows, and VT100 on Unix.

scmutil: clarify that we explicitly do termwidth - 1 on Windows I was a bit confused since we didn't add 1 to the width, which is different from the example shown in StackOverflow. http://stackoverflow.com/a/12642749

scmutil: remove superfluous indent from termwidth()

scmutil: narrow ImportError handling in termwidth() The array module must exist. It's sufficient to suppress the ImportError of termios. Also salvaged the comment why we have to handle AttributeError, from 7002bb17cc5e.

scmutil: make termwidth() obtain stdio from ui I'm getting rid of direct sys.stderr|out|in references so Py3 porting will be slightly easier.

scmutil: move util.termwidth() I'm going to get rid of sys.stderr|out|in references from posix.termwidth(). In order to do that, termwidth() needs to take a ui, but functions in util.py shouldn't depend on a ui object. So moves termwidth() to scmutil.py.

bdiff: don't check border condition in loop `plast = a + len - 1`. So, this "for" loop iterates from "a" to "plast", inclusive. So, `p == plast` can only be true on the final iteration of the loop. So checking for it on every loop iteration is wasteful. This patch simply decreases the upper bound of the loop by 1 and adds an explicit check after iteration for the `p == plast` case. We can't simply add 1 to the initial value for "i" because that doesn't do the correct thing on empty input strings. `perfbdiff -m 3041e4d59df2` on the Firefox repo becomes significantly faster: ! wall 0.072763 comb 0.070000 user 0.070000 sys 0.000000 (best of 100) ! wall 0.053221 comb 0.060000 user 0.060000 sys 0.000000 (best of 100) For the curious, this code has its origins in 8b067bde6679, which is the changeset that introduced bdiff.c in 2005. Also, GNU diffutils is able to perform a similar line-based diff in under 20ms. So there's likely more perf wins to be found in this code. One of them is the hashing algorithm. But it looks like mpm spent some time testing hash collisions in d0c48891dd4a. I'd like to do the same before switching away from lyhash, just to be on the safe side.

perf: add perfbdiff bdiff shows up a lot in profiling. I think it would be useful to have a perf command that runs bdiff over and over so we can find hot spots.

help: show help for disabled extensions (issue5228) This patch does not exactly solve issue5228 but it results in a better condition on this issue. For disabled extensions, we used to parse the module and get the first occurrences of docstring and then return the first line of that as an introductory heading of extension. This is what we get today. This patch returns the whole docstring of the module as a help for extension, which is more informative. There are some modules which don't have much docstring at top level except the heading so those are unaffected by this change. To follow the existing trend of showing commands either we have to load the extension or have a very ugly parsing method which don't even assure correctness.

py3: make scmutil.rcpath() return bytes This patch make sure scmutil.rcpath() returns bytes independent of which platform is used on Python 3. If we want to change type for windows we can just conditionalize the return variable.

py3: use pycompat.ossep at certain places Certain instances of os.sep has been converted to pycompat.ossep where it was sure to use bytes only. There are more such instances which needs some more attention and will get surely.

py3: have pycompat.ospathsep and pycompat.ossep We needed bytes version of os.sep and os.pathsep in py3 as they return unicodes.

py3: add a bytes version of os.name os.name returns unicodes on py3. Most of our checks are like os.name == 'nt' Because of the transformer, on the right hand side we have b'nt'. The condition will never satisfy even if os.name returns 'nt' as that will be an unicode. We either need to encode every occurence of os.name or have a new variable which is much cleaner. Now we have pycompat.osname. There are around 53 occurences of os.name in the codebase which needs to be replaced by pycompat.osname to support Python 3.

py3: make util.datapath a bytes variable In this patch we make util.datapath a bytes variable, but we have to pass a unicode to gettext.translation otherwise it will cry. Used pycompat.fsdecode() to decode it back to unicode as it was converted to bytes using pycompat.fsencode().

py3: add os.fsdecode() as pycompat.fsdecode() We need to use os.fsdecode() but this was not present in Python 2. So added the function in pycompat.py

statprof: return state from stop() I don't like global variables. Have stop() return the captured state so callers can pass data to the display function.