Modify wheel#unzip to preserve file execute permissions. (bazelbuild#46)

extract_wheels/__init__.py

@@ -67,9 +67,7 @@ def main() -> None:
 
     pip_args = [sys.executable, "-m", "pip", "wheel", "-r", args.requirements]
     # Assumes any errors are logged by pip so do nothing. This command will fail if pip fails
-    subprocess.check_output(
-        pip_args
-    )
+    subprocess.check_output(pip_args)
 
     extras = requirements.parse_extras(args.requirements)
 

extract_wheels/lib/wheel.py

@@ -1,13 +1,29 @@
 """Utility class to inspect an extracted wheel directory"""
 import glob
 import os
+import stat
 import zipfile
 from typing import Dict, Optional, Set
 
 import pkg_resources
 import pkginfo
 
 
+def current_umask() -> int:
+    """Get the current umask which involves having to set it temporarily."""
+    mask = os.umask(0)
+    os.umask(mask)
+    return mask
+
+
+def set_extracted_file_to_default_mode_plus_executable(path: str) -> None:
+    """
+    Make file present at path have execute for user/group/world
+    (chmod +x) is no-op on windows per python docs
+    """
+    os.chmod(path, (0o777 & ~current_umask() | 0o111))
+
+
 class Wheel:
     """Representation of the compressed .whl file"""
 
@@ -43,6 +59,19 @@ def dependencies(self, extras_requested: Optional[Set[str]] = None) -> Set[str]:
     def unzip(self, directory: str) -> None:
         with zipfile.ZipFile(self.path, "r") as whl:
             whl.extractall(directory)
+            # The following logic is borrowed from Pip:
+            # https://github.com/pypa/pip/blob/cc48c07b64f338ac5e347d90f6cb4efc22ed0d0b/src/pip/_internal/utils/unpacking.py#L240
+            for info in whl.infolist():
+                name = info.filename
+                # Do not attempt to modify directories.
+                if name.endswith("/") or name.endswith("\\"):
+                    continue
+                mode = info.external_attr >> 16
+                # if mode and regular file and any execute permissions for
+                # user/group/world?
+                if mode and stat.S_ISREG(mode) and mode & 0o111:
+                    name = os.path.join(directory, name)
+                    set_extracted_file_to_default_mode_plus_executable(name)
 
 
 def get_dist_info(wheel_dir: str) -> str: