rebase: do not abort if all changesets have equivalents in the destination

changegroup: don't send empty subdirectory manifest groups When grafting/rebasing, it is common for multiple changesets to make the same change to a subdirectory. When writing the revlog for the directory, the revlog code already takes care of not writing the entry again. In 0c2a088ffcc5 (changegroup: prune subdirectory dirlogs too, 2016-02-12), I added the corresponding code in changegroup (not sending entries the client already has), but I forgot to avoid sending the entire changegroup if no nodes remained in the pruned set. Although that's harmless besides the wasted network traffic, the receiving side was checking for it (copied from the changegroup code for handling files). This resulted in the client crashing with: abort: received dir revlog group is empty Fix by simply not emitting a changegroup for the directory if there were no changes is it. This matches how files are handled.

chg: ignore SIGINT while waiting pager termination Otherwise the terminal would be left with unclean state. This is what fcc4b55876c3 does.

chg: reset signal handlers to default before waiting pager Our signal handlers forward signals to the server process, but it will disappear soon after hgc_close(). So we should unregister handlers before hgc_close(). Otherwise chg would abort due to kill(perrpid, sig) failure. The problem is spotted by SIGWINCH while waiting pager termination.

help: document that [subpaths] may rewrite relative paths The subpaths substitution logic first attempts to match the absolute repository path, then the relative subrepository path if that failed.

doc: describe detail about checkambig optional argument This is followup for patches below, which add checkambig argument to existing function. - 731ced087a4b - 76f1ea360c7e - ce2d81aafbae - a109bf7e0dc2