tests: port test-absorb-filefixupstate to Python 3 Mostly b prefixes, but also some isinstance() checks and a couple of maplist() instances. The test now passes on Python 3. Differential Revision: https://phab.mercurial-scm.org/D4175

absorb: port partway to Python 3 Use pycompat.maplist() in the one place that matters and use the default iterator of a dict instead of iterkeys(). Two new tests pass on Python 3. Differential Revision: https://phab.mercurial-scm.org/D4174

localrepo: better error when a repo exists but we lack permissions Claiming "repository foo not found" when the repository does exist causes confusion regularly ("where is the typo?"). Differential Revision: https://phab.mercurial-scm.org/D4122

changegroup: extract _revisiondeltanormal() to standalone function It wasn't accessing anything important on the cgpacker that warranted it being a method instead of a function. Differential Revision: https://phab.mercurial-scm.org/D4142

changegroup: inline _revchunk() into group() _revchunk() was pretty minimal. I think having all the code for generating data composing the changegroup in one function makes things easier to understand. As part of the refactor, we now call the _revisiondelta* functions explicitly. This paves the road to refactor their argument signatures. Differential Revision: https://phab.mercurial-scm.org/D4141

changegroup: pass mfdicts properly With the narrow code part of core, the hacky pass-argument-via- attribute-on-self can be accomplished with a regular function argument. Differential Revision: https://phab.mercurial-scm.org/D4140

changegroup: pass sorted revisions into group() (API) Currently, group() receives a list of nodes and calls _sortgroup() to sort them and turn them into revs. Since the sorting behavior varies depending on the type of data being transferred, I think it makes sense to perform the sorting before group() is invoked. This commit extracts _sortgroup() to a pair of standalone functions. It then moves the calling of these functions to the 3 call sites of group(). group() now receives an iterable of revs instead of nodes. Differential Revision: https://phab.mercurial-scm.org/D4139

changegroup: pull _fileheader out of cgpacker It doesn't need any state from the packer. Differential Revision: https://phab.mercurial-scm.org/D4138

changegroup: factor changelogdone into an argument The variable was basically tracking whether the current operation is being performed against the changelog or something else. So let's just pass such a flag to everything that needs to access it. I'm still not a huge fan of building changelog awareness into low-level functions like revision delta generation. But passing an argument is strictly better than state on the packer instance. Differential Revision: https://phab.mercurial-scm.org/D4137

changegroup: record changelogdone after fully consuming its data Setting this as a side-effect of calling _close() is wonky. There's only one group for changelog data. So we can wait until after all data has been emitted before recording it. Differential Revision: https://phab.mercurial-scm.org/D4136