tests: add a substitution for ENOENT/ERROR_FILE_NOT_FOUND messages Automatic replacement seems better than trying to figure out a check-code rule. I didn't bother looking to see why the error message and file name is reversed in the annotate and histedit tests, based on Windows or not. I originally had this as a list of tuples, conditional on the platform. But there are a couple of 'No such file or directory' messages emitted by Mercurial itself, so unconditional is required for stability. There are also several variants of what I assume is 'connection refused' and 'unknown host' in test-clone.t and test-clonebundles.t for Docker, FreeBSD jails, etc. Yes, these are handled by (re) tags, but maybe it would be better to capture those strings in order to avoid whack-a-mole in future tests. All of this points to using a dictionary containing one or more strings-to-be-replaced values.

setup: only write some autogenerated files if they change Without this change, setup.py always writes some files on every invocation. This prevents some builds from being a no-op when they should. And, since times can sneak into generated .pyc files, this prevents file content from being deterministic between builds. As part of the refactor, we treat file content as bytes. The only potential regression from this would be if some tool is looking at mtimes of the changed files to determine if further action should be taken. But I don't think anything critically important is keyed off the mtimes of these specific files. Differential Revision: https://phab.mercurial-scm.org/D1580

python3: whitelist many more passing tests Differential Revision: https://phab.mercurial-scm.org/D1584