color: avoid shadowing a variable inside a list comprehension

memory: avoid shadowing variables inside a list comprehension

shelve: move shelve-finishing logic to a separate function With future obs-based shelve, finishing shelve will be different from just aborting a transaction and I would like to keep both variants of this functionality in a separate function.

shelve: move unknown files handling to a separate function This change has nothing to do with future obsshelve introduction, it is done just for readability purposes.

shelve: move actual created commit shelving to a separate function Currently, this code does not have any branching, it just bundles a commit and saves a patch file. Later, obsolescence-based shelve will be added, so this code will also create some obsmarkers and will be one of the few places where obsshelve will be different from traditional shelve.

shelve: move 'nothing changed' messaging to a separate function This has nothing to do with the future obsshelve implementation, I just thought that moving this messaging to a separate function will improve shelve code readability.

shelve: move commitfunc creation to a separate function Special commitfuncs are created as closures at least twice in shelve's code and one time special commitfunc is used within another closure. They all serve very specific purposes like temporarily tweak some configuration or enable editor, etc. This is not immediately important to someone reading shelve code, so I think moving this logic to a separate function is a good idea.

shelve: move mutableancestors to not be a closure There's no value in it being a closure and everyone who tries to read the outer function code will be distracted by it. IMO moving it out significantly improves readability, especially given how clear it is what mutableancestors function does from its name.

shelve: move shelve name generation to a separate function This has nothing to do with future obsshelve introduction, done just for readability purposes.

shelve: move possible shelve file extensions to a single place This and a couple of following patches are a preparation to implementing obsolescense-enabled shelve which was discussed on a Sprint. If this refactoring is not done, shelve is going to look even more hackish than now. This particular commit introduces a slight behavior change. Previously, if only .hg/shelve/name.patch file exists, but .hg/name.hg does not, 'hg shelve -d name' would fail saying "shelve not found". Now deletion will only fail if .patch file does not exist (since .patch is used as an indicator of an existing shelve). Other shelve files being absent are skipped silently to accommodate for future introduction of obs-based shelve, which will mean that for some shelves .hg and .patch files exist, while for others .hg and .oshelve.