dirstate: ensure mv source is marked deleted when walking icasefs (issue4760) Previously, importing a case-only rename patch on a case insensitive filesystem caused the original file to be marked as '!' in status. The source was being forgotten properly in patch.workingbackend.close(), but the call it makes to scmutil.marktouched() then put the file back into the 'n' state (but it was still missing from the filesystem). The cause of this was scmutil._interestingfiles() would walk dirstate, and since dirstate was able to lstat() the old file via the new name, was treating this as a forgotten file, not a removed file. scmutil.marktouched() re-adds forgotten files, so dirstate got out of sync with the filesystem. This could be handled with less code in the "kind == regkind or kind == lnkkind" branch of dirstate._walkexplicit(), but this avoids filesystem accesses unless case collisions occur. _discoverpath() is used instead of normalize(), since the dirstate case is given first precedence, and the old file is still in it. What matters is the actual case in the filesystem.