comparison mercurial/sparse.py @ 42456:87a34c767384

merge: fix race that could cause wrong size in dirstate

The problem is that hg merge/update/etc work the following way:
1. figure out what files to update
2. apply the update to disk
3. apply the update to in-memory dirstate
4. write dirstate

where step3 looks at the filesystem and assumes it sees the result of
step2. If a file is changed between step2 and step3, step3 will record
incorrect information in the dirstate.

I avoid this by passing the size step3 needs directly from step2, for
the common path (not implemented for change/delete conflicts for
instance).

I didn't fix the same race for the exec bit for now, because it's less
likely to be problematic and I had trouble due to the fact that the
dirstate stores the permissions differently from the manifest (st_mode
vs '' 'l' 'x'), in combination with tests that pretend that symlinks
are not supported.

However, I moved the lstat from step3 to step2, which should tighten
the race window markedly, both for the exec bit and for the mtime.

Differential Revision: https://phab.mercurial-scm.org/D6475

42455:5ca136bbd3f6

            actions.append((file, None, message))
            dropped.append(file)

    typeactions = mergemod.emptyactions()
    typeactions['r'] = actions
    mergemod.applyupdates(repo, typeactions, repo[None], repo['.'], False)

    # Fix dirstate
    for file in dropped:
        dirstate.drop(file)

                actions.append((file, (fctx.flags(), False), message))

        typeactions = mergemod.emptyactions()
        typeactions['g'] = actions
        mergemod.applyupdates(repo, typeactions, repo[None], repo['.'],
                              False)

        dirstate = repo.dirstate
        for file, flags, msg in actions:
            dirstate.normal(file)

    # Apply changes to disk
    typeactions = mergemod.emptyactions()
    for f, (m, args, msg) in actions.iteritems():
        typeactions[m].append((f, args, msg))

    mergemod.applyupdates(repo, typeactions, repo[None], repo['.'], False)

    # Fix dirstate
    for file in added:
        dirstate.normal(file)

42456:87a34c767384

            actions.append((file, None, message))
            dropped.append(file)

    typeactions = mergemod.emptyactions()
    typeactions['r'] = actions
    mergemod.applyupdates(repo, typeactions, repo[None], repo['.'], False,
                          wantfiledata=False)

    # Fix dirstate
    for file in dropped:
        dirstate.drop(file)

                actions.append((file, (fctx.flags(), False), message))

        typeactions = mergemod.emptyactions()
        typeactions['g'] = actions
        mergemod.applyupdates(repo, typeactions, repo[None], repo['.'],
                              False, wantfiledata=False)

        dirstate = repo.dirstate
        for file, flags, msg in actions:
            dirstate.normal(file)

    # Apply changes to disk
    typeactions = mergemod.emptyactions()
    for f, (m, args, msg) in actions.iteritems():
        typeactions[m].append((f, args, msg))

    mergemod.applyupdates(repo, typeactions, repo[None], repo['.'], False,
                          wantfiledata=False)

    # Fix dirstate
    for file in added:
        dirstate.normal(file)