mergestate: move _read() call to read constructor With this patch, mergestate.clean() will no longer abort when it encounters an unsupported merge type. However we hold off on testing it until backwards compatibility is in place.

debugmergestate: explain why we create mergestate objects directly We would normally use the read() constructor, but in this case it's fine because - we implement our own reading layer, so the extra parsing done by read() is unnecessary - read() can raise an exception for unsupported merge state records, but here we'd like to handle that separately - debugmergestate needs to be privy to mergestate internals anyway

debugdirstate: convert keyword parameters to **opts Removes the named arguments and replaces them by accessing opts. This will be used in the next patch in the series because we'll be adding more flags to debugdirstate

convert: changed test's progress output format to ignore estimate On my machine, whenever I run all test with a high -j value, test-convert-git.t would consistently fail by displaying an estimate. This patch removes that value from the output.

mq: use repo._bookmarks.recordchange instead of repo._bookmarks.write Before this patch, mq was using repo._bookmarks.write. This patch replaces this code with the recommended way of saving bookmarks changes: repo._bookmarks.recordchange.

mq: indentation change to make the next patch more legible We put the code to be indented in the next patch in a "if True:" block to make it easier to review.

bookmarks: use repo._bookmarks.recordchange instead of repo._bookmarks.write We move from the old api repo._bookmarks.write to the new api repo._bookmarks.recordchange.

localrepo: put bookmark move following commit in one transaction Before this patch, making a commit on a local repo could move a bookmark and both operations would not be grouped as one transaction. This patch makes both operations part of one transaction. This is necessary to switch to the new api to save bookmarks repo._bookmarks.recordchange if we don't want to change the current behavior of rollback. Dirstate change happening after the commit is done is now part of the transaction mentioned above. This leads to a change in the expected output of several tests. The change to test-fncache happens because both lock are now released in the same finally clause. The lock release is made explicitly buggy in this test. Previously releasing lock would crash triggering release of wlock that crashes too. Now lock release crash does not directly result in the release of wlock. Instead wlock is released at garbage collection time and the error raised at that time "confuses" python.

test-resolve.t: switch to mergestate.read() See previous patches for why we're doing this.

localrepo.commit: switch to mergestate.read() See previous patches for why we're doing this.

fileset: switch to mergestate.read() See previous patches for why we're doing this.

commands.summary: switch to mergestate.read() See previous patch for why we're doing this. We do this with a bit of care -- it would be bad form for 'hg summary' to abort completely if we encounter an unsupported merge record. Instead just warn about that and continue with the rest of the summary.

commands.resolve: switch to mergestate.read() See previous patches for why we're doing this.

shelve: switch to mergestate.read() See previous patches for why we're doing this.

mergestate: add a constructor that reads state from disk At the moment it's the same as just creating a new mergestate, but we'll soon move the _read call out of __init__ and in here.

merge.applyupdates: switch to mergestate.clean() See the previous patches for why we're doing this.

localrepo: switch to mergestate.clean() See the previous patches for why we're doing this.

strip: switch to mergestate.clean() See the previous patches for why we're doing this.

mergestate: add a constructor that sets up a clean merge state Eventually, we'll move the read call out of the constructor. This will: - avoid unnecessary reads when we're going to nuke the merge state anyway - avoid raising an exception if there's an unsupported merge record 'clean' seems like a good name for it because I wanted to avoid anything with the word 'new' in it, and 'reset' is more an action performed on a merge state than a way to get a new merge state. Thanks to Martin von Zweigbergk for feedback about naming this.

mergestate: raise structured exception for unsupported merge records We're going to catch this exception in 'hg summary' to print a better error message. This code is pretty untested, so there are no changes to test output. In upcoming patches we're going to test the output more thoroughly.

error: add a structured exception for unsupported merge records We're going to use this in summary to print a better error message.

dirstate: back out 502b56a9e897 Superseded by the parent of this commit.

osutil: make statfiles check for interrupts periodically This is a simpler and faster fix for issue4878 than the contortions performed in 502b56a9e897.

osutil: don't leak on statfiles error Found using the power of the mighty eyeball.

histedit: extracts _isdirtywc function Checking if working copy is dirty was done in few places, this patch extracts it in _isdirtywc procedure.

node: add 'nullhex', hex-encoded nullid We're going to need this for upcoming changes, because the merge state stores nodes as hex strings.

filemerge: introduce class whose objects represent files not in a context Most code is going to barf at the return values here (particularly from data and size), so we restrict it to the filemerge code. This is already somewhat supported via: ctx.filectx(f, fileid=nullid) Indeed, for add/add conflicts (ancestor doesn't have the file) we use precisely that. However, that is broken in subtle ways: - The cmp() function in filectx returns False (identical) for such a filectx when compared to a zero-length file. - size() returns 0 rather than some sort of value indicating that the file isn't present. - data() returns '' rather than some sort of value indicating that the file isn't present. Given the relatively niche use of such filectxes, this seems to be the simplest way to fix all these issues.

filectx: add isabsent method This will indicate whether this filectx represents a file that is *not* in a changectx. This will be used by merge and filemerge code to know about when a conflict is a change/delete conflict. While this is kind of hacky, it is the least bad of all the alternatives. Other options considered but rejected include: - isinstance(fctx, ...) -- not very Pythonic, doesn't support duck typing - fctx.size() is None -- the 'size()' call on workingfilectxes causes a disk stat - fctx.filenode() == nullid -- the semantics around filenode are incredibly confusing. In particular, for workingfilectxes, filenode() is always None no matter whether the file is present on disk or in either parent. Having different behavior for None versus nullid in the merge code is just asking for pain. Thanks to Pierre-Yves David for early review feedback here.

filectx: allow custom comparators We're going to introduce other sorts of filectxes very soon, and we'd like the cmp method to function properly (i.e. commutatively) for them. The only way to make that happen is for this cmp method to call into that specialized one if that defines a custom comparator.

debugmergestate: print out record type for files We're going to add a separate record type for change/delete conflicts soon. We need to make sure they get stored with the correct record type so that older versions of Mercurial correctly abort when they see change/delete records.