Fix python3 installed from the Windows Store

When meson is currently being run with a python that seems to have been
installed from the Windows Store, replace the general WindowsApps
directory in search paths with dirname(sys.executable), and also handle
failures with pathlib.resolve on WindowsApps exe files.

mesonbuild/dependencies/base.py

@@ -22,6 +22,7 @@ import json
 import shlex
 import shutil
 import stat
+import sys
 import textwrap
 import platform
 import typing as T
@@ -1844,14 +1845,22 @@ class ExternalProgram:
         # Ensure that we use USERPROFILE even when inside MSYS, MSYS2, Cygwin, etc.
         if 'USERPROFILE' not in os.environ:
             return path
-        # Ignore executables in the WindowsApps directory which are
-        # zero-sized wrappers that magically open the Windows Store to
-        # install the application.
+        # The WindowsApps directory is a bit of a problem. It contains
+        # some zero-sized .exe files which have "reparse points", that
+        # might either launch an installed application, or might open
+        # a page in the Windows Store to download the application.
+        #
+        # To handle the case where the python interpreter we're
+        # running on came from the Windows Store, if we see the
+        # WindowsApps path in the search path, replace it with
+        # dirname(sys.executable).
         appstore_dir = Path(os.environ['USERPROFILE']) / 'AppData' / 'Local' / 'Microsoft' / 'WindowsApps'
         paths = []
         for each in path.split(os.pathsep):
             if Path(each) != appstore_dir:
                 paths.append(each)
+            elif 'WindowsApps' in sys.executable:
+                paths.append(os.path.dirname(sys.executable))
         return os.pathsep.join(paths)
 
     @staticmethod

mesonbuild/interpreter.py

@@ -40,6 +40,7 @@ import shutil
 import uuid
 import re
 import shlex
+import stat
 import subprocess
 import collections
 from itertools import chain
@@ -2424,7 +2425,19 @@ class Interpreter(InterpreterBase):
         elif os.path.isfile(f) and not f.startswith('/dev'):
             srcdir = Path(self.environment.get_source_dir())
             builddir = Path(self.environment.get_build_dir())
-            f = Path(f).resolve()
+            try:
+                f = Path(f).resolve()
+            except OSError:
+                f = Path(f)
+                s = f.stat()
+                if (hasattr(s, 'st_file_attributes') and
+                        s.st_file_attributes & stat.FILE_ATTRIBUTE_REPARSE_POINT != 0 and
+                        s.st_reparse_tag == stat.IO_REPARSE_TAG_APPEXECLINK):
+                    # This is a Windows Store link which we can't
+                    # resolve, so just do our best otherwise.
+                    f = f.parent.resolve() / f.name
+                else:
+                    raise
             if builddir in f.parents:
                 return
             if srcdir in f.parents: