pyoxidizer: add user-site to `sys.path` on Windows

This is a port of 53221078e0de to Windows to allow pip-installed extensions to
be loaded without specifying a path.  It's a major headache to have an hg.exe on
`PATH` that needs to have the path to the extensions specified, because WSL
doesn't see the same path.

This is only for Windows for now, to match the currently shipping py2 behavior.
There is a better solution with using the `site` package, but this needs support
in PyOxidizer[1].

[1] https://github.com/indygreg/PyOxidizer/issues/430

Differential Revision: https://phab.mercurial-scm.org/D11308

rust/hgcli/pyoxidizer.bzl

@@ -1,303 +1,314 b''
 # The following variables can be passed in as parameters:
 #
 # VERSION
 #   Version string of program being produced.
 #
 # MSI_NAME
 #   Root name of MSI installer.
 #
 # EXTRA_MSI_FEATURES
 #   ; delimited string of extra features to advertise in the built MSA.
 #
 # SIGNING_PFX_PATH
 #   Path to code signing certificate to use.
 #
 # SIGNING_PFX_PASSWORD
 #   Password to code signing PFX file defined by SIGNING_PFX_PATH.
 #
 # SIGNING_SUBJECT_NAME
 #   String fragment in code signing certificate subject name used to find
 #   code signing certificate in Windows certificate store.
 #
 # TIME_STAMP_SERVER_URL
 #   URL of time-stamp token authority (RFC 3161) servers to stamp code signatures.
 
 ROOT = CWD + "/../.."
 
 VERSION = VARS.get("VERSION", "5.8")
 MSI_NAME = VARS.get("MSI_NAME", "mercurial")
 EXTRA_MSI_FEATURES = VARS.get("EXTRA_MSI_FEATURES")
 SIGNING_PFX_PATH = VARS.get("SIGNING_PFX_PATH")
 SIGNING_PFX_PASSWORD = VARS.get("SIGNING_PFX_PASSWORD", "")
 SIGNING_SUBJECT_NAME = VARS.get("SIGNING_SUBJECT_NAME")
 TIME_STAMP_SERVER_URL = VARS.get("TIME_STAMP_SERVER_URL", "http://timestamp.digicert.com")
 
 IS_WINDOWS = "windows" in BUILD_TARGET_TRIPLE
 
 # Code to run in Python interpreter.
 RUN_CODE = """
 import os
 import sys
 extra_path = os.environ.get('PYTHONPATH')
 if extra_path is not None:
     # extensions and hooks expect a working python environment
     # We do not prepend the values because the Mercurial library wants to be in
     # the front of the sys.path to avoid picking up other installations.
     sys.path.extend(extra_path.split(os.pathsep))
+# Add user site to sys.path to load extensions without the full path
+if os.name == 'nt':
+    vi = sys.version_info
+    sys.path.append(
+        os.path.join(
+            os.environ['APPDATA'],
+            'Python',
+            'Python%d%d' % (vi[0], vi[1]),
+            'site-packages',
+        )
+    )
 import hgdemandimport;
 hgdemandimport.enable();
 from mercurial import dispatch;
 dispatch.run();
 """
 
 set_build_path(ROOT + "/build/pyoxidizer")
 
 def make_distribution():
     return default_python_distribution(python_version = "3.9")
 
 def resource_callback(policy, resource):
     if not IS_WINDOWS:
         resource.add_location = "in-memory"
         return
 
     # We use a custom resource routing policy to influence where things are loaded
     # from.
     #
     # For Python modules and resources, we load from memory if they are in
     # the standard library and from the filesystem if not. This is because
     # parts of Mercurial and some 3rd party packages aren't yet compatible
     # with memory loading.
     #
     # For Python extension modules, we load from the filesystem because
     # this yields greatest compatibility.
     if type(resource) in ("PythonModuleSource", "PythonPackageResource", "PythonPackageDistributionResource"):
         if resource.is_stdlib:
             resource.add_location = "in-memory"
         else:
             resource.add_location = "filesystem-relative:lib"
 
     elif type(resource) == "PythonExtensionModule":
         resource.add_location = "filesystem-relative:lib"
 
 def make_exe(dist):
     """Builds a Rust-wrapped Mercurial binary."""
     packaging_policy = dist.make_python_packaging_policy()
 
     # Extension may depend on any Python functionality. Include all
     # extensions.
     packaging_policy.extension_module_filter = "all"
     packaging_policy.resources_location = "in-memory"
     if IS_WINDOWS:
         packaging_policy.resources_location_fallback = "filesystem-relative:lib"
     packaging_policy.register_resource_callback(resource_callback)
 
     config = dist.make_python_interpreter_config()
     config.allocator_backend = "default"
     config.run_command = RUN_CODE
 
     # We want to let the user load extensions from the file system
     config.filesystem_importer = True
 
     # We need this to make resourceutil happy, since it looks for sys.frozen.
     config.sys_frozen = True
     config.legacy_windows_stdio = True
 
     exe = dist.to_python_executable(
         name = "hg",
         packaging_policy = packaging_policy,
         config = config,
     )
 
     # Add Mercurial to resources.
     exe.add_python_resources(exe.pip_install(["--verbose", ROOT]))
 
     # On Windows, we install extra packages for convenience.
     if IS_WINDOWS:
         exe.add_python_resources(
             exe.pip_install(["-r", ROOT + "/contrib/packaging/requirements-windows-py3.txt"]),
         )
     extra_packages = VARS.get("extra_py_packages", "")
     if extra_packages:
         for extra in extra_packages.split(","):
             extra_src, pkgs = extra.split("=")
             pkgs = pkgs.split(":")
             exe.add_python_resources(exe.read_package_root(extra_src, pkgs))
 
     return exe
 
 def make_manifest(dist, exe):
     m = FileManifest()
     m.add_python_resource(".", exe)
 
     return m
 
 
 # This adjusts the InstallManifest produced from exe generation to provide
 # additional files found in a Windows install layout.
 def make_windows_install_layout(manifest):
     # Copy various files to new install locations. This can go away once
     # we're using the importlib resource reader.
     RECURSIVE_COPIES = {
         "lib/mercurial/locale/": "locale/",
         "lib/mercurial/templates/": "templates/",
     }
     for (search, replace) in RECURSIVE_COPIES.items():
         for path in manifest.paths():
             if path.startswith(search):
                 new_path = path.replace(search, replace)
                 print("copy %s to %s" % (path, new_path))
                 file = manifest.get_file(path)
                 manifest.add_file(file, path = new_path)
 
     # Similar to above, but with filename pattern matching.
     # lib/mercurial/helptext/**/*.txt -> helptext/
     # lib/mercurial/defaultrc/*.rc -> defaultrc/
     for path in manifest.paths():
         if path.startswith("lib/mercurial/helptext/") and path.endswith(".txt"):
             new_path = path[len("lib/mercurial/"):]
         elif path.startswith("lib/mercurial/defaultrc/") and path.endswith(".rc"):
             new_path = path[len("lib/mercurial/"):]
         else:
             continue
 
         print("copying %s to %s" % (path, new_path))
         manifest.add_file(manifest.get_file(path), path = new_path)
 
     extra_install_files = VARS.get("extra_install_files", "")
     if extra_install_files:
         for extra in extra_install_files.split(","):
             print("adding extra files from %s" % extra)
             # TODO: I expected a ** glob to work, but it didn't.
             #
             # TODO: I know this has forward-slash paths. As far as I can tell,
             # backslashes don't ever match glob() expansions in 
             # tugger-starlark, even on Windows.
             manifest.add_manifest(glob(include=[extra + "/*/*"], strip_prefix=extra+"/"))
 
     # We also install a handful of additional files.
     EXTRA_CONTRIB_FILES = [
         "bash_completion",
         "hgweb.fcgi",
         "hgweb.wsgi",
         "logo-droplets.svg",
         "mercurial.el",
         "mq.el",
         "tcsh_completion",
         "tcsh_completion_build.sh",
         "xml.rnc",
         "zsh_completion",
     ]
 
     for f in EXTRA_CONTRIB_FILES:
         manifest.add_file(FileContent(path = ROOT + "/contrib/" + f), directory = "contrib")
 
     # Individual files with full source to destination path mapping.
     EXTRA_FILES = {
         "contrib/hgk": "contrib/hgk.tcl",
         "contrib/win32/postinstall.txt": "ReleaseNotes.txt",
         "contrib/win32/ReadMe.html": "ReadMe.html",
         "doc/style.css": "doc/style.css",
         "COPYING": "Copying.txt",
     }
 
     for source, dest in EXTRA_FILES.items():
         print("adding extra file %s" % dest)
         manifest.add_file(FileContent(path = ROOT + "/" + source), path = dest)
 
     # And finally some wildcard matches.
     manifest.add_manifest(glob(
         include = [ROOT + "/contrib/vim/*"],
         strip_prefix = ROOT + "/"
     ))
     manifest.add_manifest(glob(
         include = [ROOT + "/doc/*.html"],
         strip_prefix = ROOT + "/"
     ))
 
     # But we don't ship hg-ssh on Windows, so exclude its documentation.
     manifest.remove("doc/hg-ssh.8.html")
 
     return manifest
 
 
 def make_msi(manifest):
     manifest = make_windows_install_layout(manifest)
 
     if "x86_64" in BUILD_TARGET_TRIPLE:
         platform = "x64"
     else:
         platform = "x86"
 
     manifest.add_file(
         FileContent(path = ROOT + "/contrib/packaging/wix/COPYING.rtf"),
         path = "COPYING.rtf",
     )
     manifest.remove("Copying.txt")
     manifest.add_file(
         FileContent(path = ROOT + "/contrib/win32/mercurial.ini"),
         path = "defaultrc/mercurial.rc",
     )
     manifest.add_file(
         FileContent(filename = "editor.rc", content = "[ui]\neditor = notepad\n"),
         path = "defaultrc/editor.rc",
     )
 
     wix = WiXInstaller("hg", "%s-%s.msi" % (MSI_NAME, VERSION))
 
     # Materialize files in the manifest to the install layout.
     wix.add_install_files(manifest)
 
     # From mercurial.wxs.
     wix.install_files_root_directory_id = "INSTALLDIR"
 
     # Pull in our custom .wxs files.
     defines = {
         "PyOxidizer": "1",
         "Platform": platform,
         "Version": VERSION,
         "Comments": "Installs Mercurial version %s" % VERSION,
         "PythonVersion": "3",
         "MercurialHasLib": "1",
     }
 
     if EXTRA_MSI_FEATURES:
         defines["MercurialExtraFeatures"] = EXTRA_MSI_FEATURES
 
     wix.add_wxs_file(
         ROOT + "/contrib/packaging/wix/mercurial.wxs",
         preprocessor_parameters=defines,
     )
 
     # Our .wxs references to other files. Pull those into the build environment.
     for f in ("defines.wxi", "guids.wxi", "COPYING.rtf"):
         wix.add_build_file(f, ROOT + "/contrib/packaging/wix/" + f)
 
     wix.add_build_file("mercurial.ico", ROOT + "/contrib/win32/mercurial.ico")
 
     return wix
 
 
 def register_code_signers():
     if not IS_WINDOWS:
         return
 
     if SIGNING_PFX_PATH:
         signer = code_signer_from_pfx_file(SIGNING_PFX_PATH, SIGNING_PFX_PASSWORD)
     elif SIGNING_SUBJECT_NAME:
         signer = code_signer_from_windows_store_subject(SIGNING_SUBJECT_NAME)
     else:
         signer = None
 
     if signer:
         signer.set_time_stamp_server(TIME_STAMP_SERVER_URL)
         signer.activate()
 
 
 register_code_signers()
 
 register_target("distribution", make_distribution)
 register_target("exe", make_exe, depends = ["distribution"])
 register_target("app", make_manifest, depends = ["distribution", "exe"], default = True)
 register_target("msi", make_msi, depends = ["app"])
 
 resolve_targets()