error: add InMemoryMergeConflictsError We'll raise this exception in the merge code, and in-memory users like rebase can catch it and retry without IMM. Differential Revision: https://phab.mercurial-scm.org/D1210

lfs: generate a large file by using `python` instead of yes | head yes(1) on some systems (like gcc112) feels compelled to inform you of broken pipes, such as those triggered by head(1). This works around the problem portably.

setup: add hgext.lfs to list of Python packages This is needed for lfs to get installed. Probably could stand to go into an earlier patch, but I just want to get this stuff pushed.

test-lfs: add tests demonstrating the interaction with largefiles Obviously the original series needs to be accepted first, but there are concerns about how well these extensions will play together before proceeding. It looks like the answer is surprisingly well. There are some merge surprises (largefiles seems to combine the choice of "keep tracking as a large/normal file" with taking the content of the large/normal file) and some existing diff weirdness (largefiles diffs the standins, not the large file). Converting the repo to normal files seemlessly transitions to lfs on the fly. I didn't test going the other way, because I'm not sure why anyone would want to do that. I flagged the lack of a repo requirement after converting, because some of the unsubmitted changes I have add a requirement on commit, but this somehow misses the convert case. I flagged an issue where devel-warnings are emitted on convert, which is a separate issue.