tests: simplify Windows and PYTHON3 conditionals PYTHON3 is always True. So this flow can be reduced. Differential Revision: https://phab.mercurial-scm.org/D12243

tests: delete some not PYTHON3 blocks These can never be used anymore. Differential Revision: https://phab.mercurial-scm.org/D12242

tests: unconditionalize _bytes2sys() As part of requiring Python 3. Differential Revision: https://phab.mercurial-scm.org/D12241

tests: remove Python 3 conditionalizing from variables Differential Revision: https://phab.mercurial-scm.org/D12240

tests: always encode session Differential Revision: https://phab.mercurial-scm.org/D12239

tests: unconditionalize bchr We could probably just do bytes([x]) everywhere. But this eliminates use of PYTHON3. Differential Revision: https://phab.mercurial-scm.org/D12238

tests: unconditionalize _unified_diff Now that we're Python 3 only we can make this logic simpler. Differential Revision: https://phab.mercurial-scm.org/D12237

tests: collapse elif PYTHON3 block PYTHON3 is always True now so this logic should be identical as to before. Differential Revision: https://phab.mercurial-scm.org/D12236

tests: collapse some more trivial if PYTHON3 blocks This doesn't account for all of the references to PYTHON3. But it accounts for the ones that are more trivial and don't entail logical changes. Differential Revision: https://phab.mercurial-scm.org/D12235

tests: require Python 3.5+ in run-tests.py We change the version check logic to hard fail if running on <= 3.5.0. The branch for <3.5 has been deleted. And the >=3.5 branch block has been dedented. Differential Revision: https://phab.mercurial-scm.org/D12234

revlog: use rust rank computation if available Differential Revision: https://phab.mercurial-scm.org/D12212

rust: expose rank computation function to python Differential Revision: https://phab.mercurial-scm.org/D12211

rust: implement vcsgraph::RankedGraph for Index Differential Revision: https://phab.mercurial-scm.org/D12210

revlog: implement fast_rank retrieval in C This will be useful in particular to avoid going through the Python interpreter in native Rust functions. Differential Revision: https://phab.mercurial-scm.org/D12209

revlog: return 0 for the fast_rank of nullrev By convention, the rank of the null revision is 0. This particular revision is never "physically" stored in the changelog, so it is a special case. For consistency, the value `None` is still being returned for revlogs which do not store the fast_rank property for any revision. Differential Revision: https://phab.mercurial-scm.org/D12208

setup: drop support for Python 3.5 We talked about this on the mailing list [1] and there seemed to be agreement that Python 3.5 is effectively dead and no longer worth supporting. So this commit changes our minimum version requirement to 3.6.2. [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2022-February/147885.html Differential Revision: https://phab.mercurial-scm.org/D12315

packaging: remove requirements constraints to support Python 2 We just deleted support for Python 2 from the packaging code. We no longer need these package constraints in the requirements file to support Python 2. Differential Revision: https://phab.mercurial-scm.org/D12267

packaging: remove py2exe / Python 2.7 support This commit started by deleting references to py2exe (which is only used on Python 2). After pulling the thread, quite a lot of code was orphaned and was deleted. Differential Revision: https://phab.mercurial-scm.org/D12265

automation: delete code related to Python 2.7 support The building of Inno and WiX installers took a python_version argument that allowed us to specify "2" or "3" for the major Python version. Since we no longer support Python 2, we can delete this argument and everything feeding into it. Differential Revision: https://phab.mercurial-scm.org/D12264

automation: drop support for Python 2.7 in Windows environment We stop installing Python 2.7 in the Windows environment. We remove support for building Python 2.7 wheels and installers. There is still some Python 2.7 support cleanup to perform in automation. But this removes the biggest remaining chunk of references to 2.7. Differential Revision: https://phab.mercurial-scm.org/D12263

automation: drop support for Python 2.7 in Linux environment We stop installing Python 2.7 via pyenv. We stop installing the system Python 2 packages. We delete support for running tests on Python 2.7. Differential Revision: https://phab.mercurial-scm.org/D12262

automation: make system3 the default for run-tests-linux We'll soon drop support for Python 2.7. Let's use Python 3 by default. Differential Revision: https://phab.mercurial-scm.org/D12261

automation: run hg with python3 Python 2.7 support will go away soon. Let's use Python 3 as part of the automation. Differential Revision: https://phab.mercurial-scm.org/D12260

rust: enable Python 3 support unconditionally Note: `cpython/python3-sys` is a default feature. Differential Revision: https://phab.mercurial-scm.org/D12316

cext: really remove Python 2 file handling code Disclaimer: This is _WIN32 code and I have no machine to test.

cext: backout e9ca736f5b52 "remove Python 2 file handling code" It's if"n"def.

rust: jettison Python 2 support Differential Revision: https://phab.mercurial-scm.org/D12283

setup: always decode xcode version Not decoding was a Python 2 thing. Differential Revision: https://phab.mercurial-scm.org/D12282

setup: remove Rust support for Python 2 Differential Revision: https://phab.mercurial-scm.org/D12281

cleanup: stop bundling concurrent.futures on Python 2 We no longer support Python 2. Differential Revision: https://phab.mercurial-scm.org/D12280