changelog: load pending file directly When changelogs are written, a copy of the index (or inline revlog) may be written to an 00changelog.i.a file to facilitate hooks and other processes having access to the pending data before it is finalized. The way it works today, the localrepo class loads the changelog like normal. Then, if it detects a pending transaction, it asks the changelog class to load a pending changelog. The changelog class looks for a 00changelog.i.a file. If it exists, it is loaded and internal data structures on the new revlog class are copied to the original instance. The existing mechanism is inefficient because it loads 2 revlog files. The index, node map, and chunk cache for 00changelog.i are thrown away and replaced by those for 00changelog.i.a. The existing mechanism is also brittle because it is a layering violation to access the data structures being accessed. For example, the code copies the "chunk cache" because for inline revlogs this cache contains the raw revision chunks and allows the original changelog/revlog instance to access revision data for these pending revisions. This whole behavior of course relies on the revlog constructor reading the entirety of an inline revlog into memory and caching it. That's why it is brittle. (I discovered all this as part of modifying behavior of the chunk cache.) This patch streamlines the loading of a pending 00changelog.i.a revlog by doing it directly in the changelog constructor if told to do so. When this code path is active, we no longer load the 00changelog.i file at all. The only negative outcome I see from this change is if loading 00changelog.i was somehow facilitating a role. But I can't imagine what that would be because we throw away its data (the index data structures are replaced and inline revision data is replaced via the chunk cache) and since 00changelog.i.a is a copy of 00changelog.i, file content should be identical, so there should be no meaninful file integrity checking at play. I think this was all just sub-optimal code.

cleanup: use set literals We no longer support Python 2.6, so we can now use set literals.

py3: convert date and format arguments str before passing in time.strptime time.strptime() raises ValueError if the arguments are not str. Source Code: https://hg.python.org/cpython/file/3.5/Lib/_strptime.py#l307

py3: convert kwargs' keys to str using pycompat.strkwargs

verify: add a config option to skip certain flag processors Previously, "hg verify" verifies everything, which could be undesirable when there are expensive flag processor contents. This patch adds a "verify.skipflags" developer config. A flag processor will be skipped if (flag & verify.skipflags) == 0. In the LFS usecase, that means "hg verify --config verify.skipflags=8192" will not download all LFS blobs, which could be too large to be stored locally. Note: "renamed" is also skipped since its default implementation may call filelog.data() which will trigger the flag processor.

changegroup: add bundlecaps back Commit 282b288aa20c333c removed the unused bundlecaps argument from the changegroup code. While it is unused in core Mercurial, it was an important feature for the remotefilelog extension because it allowed the exchange layer to communicate to the changegroup packer that this was a shallow repo and that filelogs should not be included. Without bundlecaps, there is currently no other way to pass that information along without a more extensive refactor of exchange, bundle, and changegroup code. This patch backs out the original removal, and merges it with some recent changes to changegroup apis.

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.