Skip to content
  • Gregory Szorc's avatar
    pyoxidizer: produce working Python 3 Windows installers (issue6366) · 57b5452a55d5
    Gregory Szorc authored
    While we've had code to produce Python 3 Windows installers with
    PyOxidizer, we haven't been advertising them on the web site due to
    a bug in making TLS connections and issues around resource handling.
    
    This commit upgrades our PyOxidizer install and configuration to
    use a recent Git commit of PyOxidizer. This new version of PyOxidizer
    contains a *ton* of changes, improvements, and bug fixes. Notably,
    Windows shared distributions now mostly "just work" and the TLS bug
    and random problems with Python extension modules in the standard
    library go away. And Python has been upgraded from 3.7 to 3.8.6.
    
    The price we pay for this upgrade is a ton of backwards incompatible
    changes to Starlark.
    
    I applied this commit (the overall series actually) on stable to
    produce Windows installers for Mercurial 5.5.2, which I published
    shortly before submitting this commit for review.
    
    In order to get the stable branch working, I decided to take a
    less aggressive approach to Python resource management. Previously,
    we were attempting to load all Python modules from memory and were
    performing some hacks to copy Mercurial's non-module resources
    into additional directories in Starlark. This commit implements
    a resource callback function in Starlark (a new feature since
    PyOxidizer 0.7) to dynamically assign standard library resources
    to in-memory loading and all other resources to filesystem loading.
    This means that Mercurial's files and all the other packages we ship
    in the Windows installers (e.g. certifi and pygments) are loaded
    from the filesystem instead of from memory. This avoids issues
    due to lack of __file__ and enables us to ship a working Python
    3 installer on Windows.
    
    The end state of the install layout after this patch is not
    ideal for @: we still copy resource files like templates and
    help text to directories next to the hg.exe executable. There
    is code in @ to use importlib.resources to load these files and
    we could likely remove these copies once this lands on @. But for
    now, the install layout mimics what we've shipped for seemingly
    forever and is backwards compatible. It allows us to achieve the
    milestone of working Python 3 Windows installers and gets us a
    giant step closer to deleting Python 2.
    
    Differential Revision: https://phab.mercurial-scm.org/D9148
    57b5452a55d5