record: update comment to match code

Commit 205599e31870 changed how newfiles get passed to commitfunc, but
did not change the corresponding comment that explains this. This
commit also updates this comment.
pack_dirstate: in C version, for invalidation set dict to what we write to disk

For files written out in the last second, Mercurial used to invalidate all the
stat data (state, size, mode, mtime) while persisting to disk. This included
invalidating the data in the dirstate dict as well.

In commit 187bf2dde7c1, this was found to be unnecessary, and Mercurial
switched to invalidating only the mtime. However, in the C version of
pack_dirstate the value set in the dict was still the fully invalidated one.

Switch to invalidating just the mtime in the dict as well.
parsers: remove no longer used dirstate_unset
dirstate: add dirstatetuple to create dirstate values

Upcoming patches will switch away from using Python tuples for dirstate values
in compiled builds.  Make that easier by introducing a variable called
dirstatetuple, currently set to tuple. In upcoming patches, this will be set to
an object from the parsers module.
parsers: inline fields of dirstate values in C version

Previously, while unpacking the dirstate we'd create 3-4 new CPython objects
for most dirstate values:

- the state is a single character string, which is pooled by CPython
- the mode is a new object if it isn't 0 due to being in the lookup set
- the size is a new object if it is greater than 255
- the mtime is a new object if it isn't -1 due to being in the lookup set
- the tuple to contain them all

In some cases such as regular hg status, we actually look at all the objects.
In other cases like hg add, hg status for a subdirectory, or hg status with the
third-party hgwatchman enabled, we look at almost none of the objects.

This patch eliminates most object creation in these cases by defining a custom
C struct that is exposed to Python with an interface similar to a tuple. Only
when tuple elements are actually requested are the respective objects created.

The gains, where they're expected, are significant. The following tests are run
against a working copy with over 270,000 files.

parse_dirstate becomes significantly faster:

$ hg perfdirstate
before: wall 0.186437 comb 0.180000 user 0.160000 sys 0.020000 (best of 35)
after:  wall 0.093158 comb 0.100000 user 0.090000 sys 0.010000 (best of 95)

and as a result, several commands benefit:

$ time hg status  # with hgwatchman enabled
before: 0.42s user 0.14s system 99% cpu 0.563 total
after:  0.34s user 0.12s system 99% cpu 0.471 total

$ time hg add new-file
before: 0.85s user 0.18s system 99% cpu 1.033 total
after:  0.76s user 0.17s system 99% cpu 0.931 total

There is a slight regression in regular status performance, but this is fixed
in an upcoming patch.
dirstate.status: assign members one by one instead of unpacking the tuple

With this patch, hg status and hg diff regain their previous speed.

The following tests are run against a working copy with over 270,000 files.
Here, 'before' means without this or the previous patch applied.

Note that in this case `hg perfstatus` isn't representative since it doesn't
take dirstate parsing time into account.

$ time hg status  # best of 5
before: 2.03s user 1.25s system 99% cpu 3.290 total
after:  2.01s user 1.25s system 99% cpu 3.261 total

$ time hg diff    # best of 5
before: 1.32s user 0.78s system 99% cpu 2.105 total
after:  1.27s user 0.79s system 99% cpu 2.066 total
dirstate.status: assign members one by one instead of unpacking the tuple

With this patch, hg status and hg diff regain their previous speed.

The following tests are run against a working copy with over 270,000 files.
Here, 'before' means without this or the previous patch applied.

Note that in this case `hg perfstatus` isn't representative since it doesn't
take dirstate parsing time into account.

$ time hg status  # best of 5
before: 2.03s user 1.25s system 99% cpu 3.290 total
after:  2.01s user 1.25s system 99% cpu 3.261 total

$ time hg diff    # best of 5
before: 1.32s user 0.78s system 99% cpu 2.105 total
after:  1.27s user 0.79s system 99% cpu 2.066 total
hg: add support for HGUNICODEPEDANTRY environment variable

This lets us easily verify that there are no implicit conversions
between unicodes and bytes in Mercurial's codebase. Based on something
mpm did by hand periodically, but it kept regressing, so just open the
door to running it in a buildbot.
config: move config.sortdict class into util

This makes it more natural to use the sortdict class from outside config.py.
tags: read tag info into a sorted dict (rather than into a regular dict)

This lets us preserve the original tag order (as specified on the .hgtags file
that is being read). This will be useful to preserve the tag order when saving
the result of a successful automated .hgtags merge (which will be introduced on
a future patch).

There shouldn't be much impact on performance because the sortdict that
_readtags returns is then used to update the alltags regular dict (which
remains a regular dict).
match: make glob '**/' match the empty string

Previously, a glob pattern of the form 'foo/**/bar' would match 'foo/a/bar' but
not 'foo/bar'. That was because the '**' in 'foo/**/bar' would be translated to
'.*', making the final regex pattern 'foo/.*/bar'. That pattern doesn't match
the string 'foo/bar'.

This is a bug because the '**/' glob matches the empty string in standard Unix
shells like bash and zsh.

Fix that by making the ending '/' optional if an empty string can be matched.

--HG--
branch : stable
merge with stable