win32: 'raise ctypes.WinError' -> 'raise ctypes.WinError()' WinError is a function that creates an Error, not an Error itself. This is a partial backout of e34106fa0dc3.

patch.diff: add support for diffs relative to a subdirectory For now this implementation is pretty naive -- it filters out files right before passing them into trydiff. In upcoming patches we'll add some more smarts.

patch.trydiff: add support for stripping a relative root This assumes that if relroot is not None, all the files in modified, added and removed start with it. In upcoming patches we'll follow that.

merge with stable

obsolete: mark warning for translation No good reason not to.

subrepo: add basic support to hgsubrepo for the files command Paths into the subrepo are not yet supported. The need to use the workingctx in the subrepo will likely be used more in the future, with the proposed working directory revset symbol. It is also needed with archive, if that code is to be reused to support 'extdiff -S'. Unfortunately, it doesn't seem possible to put the smarts in subrepo.subrepo(), as it breaks various status and diff tests. I opted not to pass the desired revision into the subrepo method explicitly, because the only ones that do pass an explicit revision are methods like status and diff, which actually operate on two contexts- the subrepo state and the explicitly passed revision.

mergecopies: reuse ancestry context when traversing file history (issue4537) Merge copies is traversing file history in search for copies and renames. Since 3.3 we are doing "linkrev adjustment" to ensure duplicated filelog entry does not confuse the traversal. This "linkrev adjustment" involved ancestry testing and walking in the changeset graph. If we do such walk in the changesets graph for each file, we end up with a 'O(<changesets>x<files>)' complexity that create massive issue. For examples, grafting a changeset in Mozilla's repo moved from 6 seconds to more than 3 minutes. There is a mechanism to reuse such ancestors computation between all files. But it has to be manually set up in situation were it make sense to take such shortcut. This changesets set this mechanism up and bring back the graph time from 3 minutes to 8 seconds. To do so, we need a bigger control on the way 'filectx' are instantiated during each 'checkcopies' calls that 'mergecopies' is doing. We add a new 'setupctx' that configure and return a 'filectx' factory. The function make sure the ancestry context is properly created and the factory make sure it is properly installed on returned 'filectx'.

adjustlinkrev: handle 'None' value as source When the source rev value is 'None', the ctx is a working context. We cannot compute the ancestors from there so we directly skip to its parents. This will be necessary to allow 'None' value for '_descendantrev' itself necessary to make all contexts used in 'mergecopies' reuse the same '_ancestrycontext'.