packaging: support building Inno installer with PyOxidizer We want to start distributing Mercurial on Python 3 on Windows. PyOxidizer will be our vehicle for achieving that. This commit implements basic support for producing Inno installers using PyOxidizer. While it is an eventual goal of PyOxidizer to produce installers, those features aren't yet implemented. So our strategy for producing Mercurial installers is similar to what we've been doing with py2exe: invoke a build system to produce files then stage those files into a directory so they can be turned into an installer. We had to make significant alterations to the pyoxidizer.bzl config file to get it to produce the files that we desire for a Windows install. This meant differentiating the build targets so we can target Windows specifically. We've added a new module to hgpackaging to deal with interacting with PyOxidizer. It is similar to pyexe: we invoke a build process then copy files to a staging directory. Ideally these extra files would be defined in pyoxidizer.bzl. But I don't think it is worth doing at this time, as PyOxidizer's config files are lacking some features to make this turnkey. The rest of the change is introducing a variant of the Inno installer code that invokes PyOxidizer instead of py2exe. Comparing the Python 2.7 based Inno installers with this one, the following changes were observed: * No lib/*.{pyd, dll} files * No Microsoft.VC90.CRT.manifest * No msvc{m,p,r}90.dll files * python27.dll replaced with python37.dll * Add vcruntime140.dll file The disappearance of the .pyd and .dll files is acceptable, as PyOxidizer has embedded these in hg.exe and loads them from memory. The disappearance of the *90* files is acceptable because those provide the Visual C++ 9 runtime, as required by Python 2.7. Similarly, the appearance of vcruntime140.dll is a requirement of Python 3.7. Differential Revision: https://phab.mercurial-scm.org/D8473

packaging: split Inno installer building from Mercurial building We want to make the logic for producing the installer agnostic about how Mercurial is built to allow for alternate build methods (like PyOxidizer). Differential Revision: https://phab.mercurial-scm.org/D8472

packaging: remove pyoxidizer.bzl from packaging directory We have another version in rust/hgcli that is more modern and is already associated with our Rust CLI project. Differential Revision: https://phab.mercurial-scm.org/D8471

contrib: install PyOxidizer in Linux and Windows environments For Linux, this was trivial. For Windows, we need to teach the powershell script to install Rust as well. This was also pretty straightforward. Differential Revision: https://phab.mercurial-scm.org/D8468

diff: re-establish linear runtime performance The previous method with sum() and list() creates a new list object for every hunk. Then sum() is used to flatten out this sequence of lists. The sum() function is not "lazy", but creates a new list object for every "+" operation and so this code had quadratic runtime behaviour.

copies: fix the changeset based algorithm regarding merge In 99ebde4fec99, we changed the list of files stored into the `files` field. This lead to the changeset centric copy algorithm to break in various merge situation involving merge. Older information could reach the merge through `p1`, and while information from `p2` was strictly fresher, it would get overwritten anyway. We update the situation with more details about which revision introduces rename information. This help use making the right decision in case of merge. We are now running a more comprehensive suite of test with include this kind of situation. The behavior differ slightly from the filelog based in a couple of instance. There is mostly two distinct cases: 1) there are conflicting rename information in a merge (different rename history on each side). In this case the filelog based implementation arbitrarily pick a side based on the file-revision-number. So it depends on a local factor. The changeset centric algorithm will use a deterministic approach, by picking the information coming from the first parent of the merge. This is stable across different clone. 2) rename information related to file that exist in both source and destination. The filelog based implementation do not even try to detect these, however the changeset centric one get them for "free" (it is simpler to detect them than not). The new implementation focus on correctness. Performance improvement will come later. Differential Revision: https://phab.mercurial-scm.org/D8244

merge with stable

rust-chg: clean up excessive indents Differential Revision: https://phab.mercurial-scm.org/D8450