building: limit package import in binary dependency analysis to Windows

Limit the collected package import in the binary dependency analysis
subprocess (performed prior to the actual analysis) to Windows.

Windows is the only platform where the packages' initialization
code can modify shared library search paths (either by modifying
`PATH` environment variables, or by calling `os.add_dll_search_path`),
so importing the collected packages to initialize the environment
makes sense only there.

Furthermore, non-deterministic package import order may cause issues
with particular package combinations and import orders, so it is
better to avoid it where we do not need it (i.e., on non-Windows
platforms).

PyInstaller/building/build_main.py

@@ -159,32 +159,37 @@ def find_binary_dependencies(binaries, binding_redirects, import_packages):
     if compat.is_win:
         extra_libdirs.append(compat.base_prefix)
 
-    # On Windows with python >= 3.8, attempt to track calls to os.add_dll_directory() to obtain DLL search paths that
-    # are dynamically set during packages' initialization.
-    if compat.is_win and compat.is_py38:
-        added_dll_directories = []
-        _orig_add_dll_directory = os.add_dll_directory
+    # On Windows, packages' initialization code might register additional DLL search paths, either by modifying the
+    # `PATH` environment variable, or (on pythonn >= 3.8) by calling `os.add_dll_directory`. Therefore, we import
+    # all collected packages, and track changes made to the environment.
+    if compat.is_win:
+        # Track changes made via `os.add_dll_directory`.
+        if compat.is_py38:
+            added_dll_directories = []
+            _orig_add_dll_directory = os.add_dll_directory
 
-        def _pyi_add_dll_directory(path):
-            added_dll_directories.append(path)
-            return _orig_add_dll_directory(path)
+            def _pyi_add_dll_directory(path):
+                added_dll_directories.append(path)
+                return _orig_add_dll_directory(path)
 
-        os.add_dll_directory = _pyi_add_dll_directory
+            os.add_dll_directory = _pyi_add_dll_directory
 
-    # Import collected packages to set up environment
-    for package in import_packages:
-        try:
-            __import__(package)
-        except Exception:
-            pass
+        # Import collected packages to set up environment.
+        for package in import_packages:
+            try:
+                __import__(package)
+            except Exception:
+                pass
 
-    # Process extra search paths on Windows
-    if compat.is_win:
+        # Process extra search paths...
         # Directories added via os.add_dll_directory() calls.
         if compat.is_py38:
             logger.info("Extra DLL search directories (AddDllDirectory): %r", added_dll_directories)
             extra_libdirs += added_dll_directories
 
+            # Restore original function
+            os.add_dll_directory = _orig_add_dll_directory
+
         # Directories set via PATH environment variable.
         # NOTE: PATH might contain empty entries that need to be filtered out.
         path_directories = [directory for directory in os.environ.get("PATH", '').split(os.pathsep) if directory]

news/7698.bugfix.rst

@@ -0,0 +1,4 @@
+Limit the import of collected packages prior to performing binary
+dependency analysis to only Windows, where it is actually useful.
+On non-Windows platforms, there is no benefit to it, and it might
+cause issues with particular orders of package imports.