lfs: prefetch lfs blobs when applying merge updates In addition to merge, this method ultimately gets called by many commands: - backout - bisect - clone - fetch - graft - import (without --bypass) - pull -u - rebase - strip - share - transplant - unbundle - update Additionally, it's also called by histedit, shelve, unshelve, and split, but it seems that the related blobs should always be available locally for these. For `hg update`, it happens after the normal argument checking and pre-update hook processing, and remote corruption is detected prior to manipulating the working directory. Other commands could use this treatment (archive, cat, revert, etc), but this covers so many of the frequently used bulk commands, it seems like a good starting point. Losing the verbose message that prints the file name before a corrupt blob aborts the command is a little sad, because there's no easy way to go from oid to file name. I'd like to change that message to list the file name so it looks cleaner and less cryptic, but the pointer object is nowhere near where it needs to be to do this. So punt on that for now.

lfs: factor out a method for extracting the pointer of a single file This will be useful for filesets, among other things, instead of traversing the whole context.

py3: add b'' to literals in check-config.py # skip-blame because we are just adding b'' Differential Revision: https://phab.mercurial-scm.org/D2046

check-config: specify the mode 'rb' to open the file Differential Revision: https://phab.mercurial-scm.org/D2045

py3: use open() instead of file() file() is not present in Python 3 Differential Revision: https://phab.mercurial-scm.org/D2044

py3: use pycompat.strkwargs() to convert kwargs' key to str Differential Revision: https://phab.mercurial-scm.org/D2043

py3: add __bytes__() for mq.patchheader and make sure __str__ returns str Before this patch, __str__() function for mq.patchheader class return bytes which is not str on Python 3. So let's move that logic to __bytes__() and for __str__() convert the return value of __bytes__() to str. Differential Revision: https://phab.mercurial-scm.org/D2042

py3: use "%d" to convert integer to bytes Differential Revision: https://phab.mercurial-scm.org/D2041

py3: use .startswith() instead of bytes[0] Differential Revision: https://phab.mercurial-scm.org/D2040

py3: slice on bytes to prevent getting the ascii values Differential Revision: https://phab.mercurial-scm.org/D2039

py3: add r'' to convert keys to keyword arguments to str # skip-blame as we are just adding r'' Differential Revision: https://phab.mercurial-scm.org/D2038

py3: add b'' to tweakdefaults config string The tweakdefaults config string is enclosed inside triple quotes and the transformer does not adds b'' there. # skip-blame because we are just adding b'' Differential Revision: https://phab.mercurial-scm.org/D2037

cmdutil: introduce deprecated aliases c8e2d6ed1f9e moved some objects used by Evolve and hence broke the latest Evolve revision. Next Evolve version will use the new objects when available but introduce deprecated aliases so users using older version of Evolve won't have a broken Evolve extension. Differential Revision: https://phab.mercurial-scm.org/D2023

makefile: remove Ubuntu Yakkety and Zesty docker targets Yakkety (16.10) was supported until 2017-07-20 and Zesty (17.04) was supported until 2018-01-13.

merge: use operation-provided labels (ex: dest/source) in several merge-tools Tools that did not use labels already, used only one, or used some label other than the exact strings of "local" or "other" were unmodified. Cases that used the label "base" were modified as well, if they were otherwise changed in this CL; "merged" was *not* changed. There are other possible changes we might want to make, but I didn't: - bcompare (linux and osx) uses the labels "parent1" and "parent2" instead of "local" and "other", so it was left alone, even though beyondcompare3 (windows) *was* changed. - araxis used the labels "Other", "Base", and "Local :$local", so it was also left alone. - UltraCompare didn't provide a label for 'local', just for 'base' and 'other', so it was left alone. Differential Revision: https://phab.mercurial-scm.org/D2012

filemerge: support passing labels to external merge tools This adds $labellocal, $labelother, and $labelbase to the replacement set for merge-tools.<tool>.args config variables, and to the environment as HG_MY_LABEL, HG_OTHER_LABEL, and HG_BASE_LABEL, respectively. We also add merge-tools.<tool>.mergemarkers and merge-tools.<tool>.mergemarkertemplate config variables as counterparts of the variables available in [ui]. We are intentionally *not* respecting ui.mergemarkers when calling out to external merge programs; too often the default template will be too wide to display comfortably in most GUIs. Differential Revision: https://phab.mercurial-scm.org/D2011