automation: support building Python 3 Inno installers The core packaging code now supports building Python 3 installers using PyOxidizer. Let's teach the automation code to invoke it so that we produce both Python 2 and Python 3 based exe installers. When publishing the artifacts, the Python 3 versions are preferred over the Python 2 versions given their higher weight (10 versus 9). This may be a controversial change. But I think making Python 3 the default is warranted, as it is the future. The Python 2 installers are still fully supported and can be installed should issues with Python 3 arise. Differential Revision: https://phab.mercurial-scm.org/D8483

automation: add extra arguments when building Inno These were being fed into the template expansion but not being used. This meant --version was not getting set when it should have been. Differential Revision: https://phab.mercurial-scm.org/D8482

packaging: add -python2 to Windows installer filenames We just taught the Windows installers to produce Python 3 variants built with PyOxidizer. Our plan is to publish both Python 2 and Python 3 versions of the installers for Mercurial 5.4. This commit teaches the Inno and WiX installers to add an optional string suffix to the installer name. On Python 2, that suffix is "-python2." We reserve the existing name for the Python 3 installers, which we want to make the default. Differential Revision: https://phab.mercurial-scm.org/D8479

automation: support building Windows wheels for Python 3.7 and 3.8 The time has come to support Python 3 on Windows. Let's teach our automation code to produce Windows wheels for Python 3.7 and 3.8. We could theoretically support 3.5 and 3.6. But I don't think it is worth it. People on Windows generally use the Mercurial installers, not wheels. And I'd prefer we limit variability and not have to worry about supporting earlier Python versions if it can be helped. As part of this, we change the invocation of pip to `python.exe -m pip`, as this is what is being recommended in Python docs these days. And it seemed to be required to avoid a weird build error. Why, I'm not sure. But it looks like pip was having trouble finding a Visual Studio files when invoked as `pip.exe` but not when using `python.exe -m pip`. Who knows. Differential Revision: https://phab.mercurial-scm.org/D8478

packaging: support building WiX installers with PyOxidizer We initially implemented PyOxidizer support for Inno installers. That did most of the heavy work of integrating PyOxidizer into the packaging system. Implementing WiX installer support was pretty straightforward. Aspects of this patch look very similar to Inno's. The main difference is the handling of the Visual C++ Redistributable Runtime files. The WiX installer was formerly using merge modules to install the VC++ 9.0 runtime because this feature is supported by the WiX installer (it isn't easily available to Inno installers). Our strategy for the runtime files is to install the vcruntime140.dll file next to hg.exe just like any other file. While we could leverage WiX's functionality for invoking a VCRedist installer, I don't want to deal with the complexity at this juncture. So, we let run_pyoxidizer() copy vcruntime140.dll into the staging directory (like it does for Inno) and our dynamic WiX XML generator picks it up as a regular file and installs it. We did, however, have to teach mercurial.wxs how to conditionally use the merge modules. But this was rather straightforward. Comparing the file layout of the WiX installers before and after: * Various lib/*.{pyd, dll} files no longer exist * python27.dll was replaced by python37.dll * vcruntime140.dll was added All these changes are expected due to the transition to Python 3 and to PyOxidizer, which embeded the .pyd and .dll files in hg.exe. Differential Revision: https://phab.mercurial-scm.org/D8477

packaging: move version derivation to run_wix_packaging() With the previous commit moving signing inline, we no longer need to compute the version string in build_installer() and can instead move this logic to run_wix_packaging(). This makes the logic in build_installer() simpler, which makes it easier to implement alternate building mechanisms. Differential Revision: https://phab.mercurial-scm.org/D8476

packaging: integrate signing into run_wix_packaging() Previously, signing was implemented via a separate function which called build_installer() and then called signing functionality. In this model, in order to implement an alternative build mechanism, we would have to invent a new variant to handle signing as well. This commit merges the signing logic into the function invoking wix. If we pass an argument holding metadata about how to sign, we sign hg.exe and the installer. This means all we have to do is pass in signing info and the signing just works. A slight change here is that signing of hg.exe happens in the staging directory as opposed to before the staging directory is populated. I don't think this matters. Differential Revision: https://phab.mercurial-scm.org/D8475

packaging: isolate invocation of WiX to own function Like we did for Inno, we want to split out the building of Mercurial from invoking the packaging tool so that we can introduce an alternate build mechanism. As part of this refactor, there are inconsequential changes to file layouts. Before, some shared files such as the WiX binaries and merge modules would be installed under build/. Now, they are installed under build/wix-*. This is to keep implementation simpler. But it also helps keep build state more isolated. Differential Revision: https://phab.mercurial-scm.org/D8474