Ensure a writeable PEX_ROOT under Variables access too.

pex/dist_metadata.py

@@ -2,7 +2,7 @@
 # Copyright 2020 Pex project contributors.
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
-from __future__ import absolute_import, print_function
+from __future__ import absolute_import
 
 import errno
 import functools
@@ -376,12 +376,9 @@ def iter_metadata_files(
 ):
     # type: (...) -> Iterator[MetadataFiles]
 
-    debug = "_PEX_DEBUG" in os.environ
     files = []
     for metadata_type in restrict_types_to or MetadataType.values():
         key = MetadataKey(metadata_type=metadata_type, location=location)
-        if debug:
-            print(">>> looking for metadata", key, "rescan?:", rescan, file=sys.stderr)
         if rescan:
             _METADATA_FILES.pop(key, None)
         if key not in _METADATA_FILES:
@@ -397,16 +394,6 @@ def iter_metadata_files(
                     metadata_files = find_wheel_metadata(location)
                     if metadata_files:
                         listing.append(metadata_files)
-                elif debug:
-                    print(">>> location has unexpected file type", file=sys.stderr)
-                    print("... isfile", os.path.isfile(location), file=sys.stderr)
-                    print("... isdir", os.path.isdir(location), file=sys.stderr)
-                    print("... islink", os.path.islink(location), file=sys.stderr)
-                    if os.path.islink(location):
-                        link = os.readlink(location)
-                        print("    ->", link, file=sys.stderr)
-                        print("       exists?:", os.path.exists(link), file=sys.stderr)
-                        print("    RP:", os.path.realpath(location), file=sys.stderr)
             elif MetadataType.EGG_INFO is metadata_type and os.path.isdir(location):
                 listing.extend(
                     _find_installed_metadata_files(

pex/pex_info.py

@@ -5,12 +5,11 @@
 
 import json
 import os
-import tempfile
 import zipfile
 
 from pex import layout, pex_warnings, variables
 from pex.cache import root as cache_root
-from pex.common import can_write_dir, open_zip, safe_mkdtemp, touch
+from pex.common import can_write_dir, open_zip, safe_mkdtemp
 from pex.compatibility import PY2, WINDOWS
 from pex.compatibility import string as compatibility_string
 from pex.inherit_path import InheritPath
@@ -511,14 +510,7 @@ def pex_root(self):
         # type: () -> str
         pex_root = os.path.realpath(os.path.expanduser(self.raw_pex_root))
         if not can_write_dir(pex_root):
-            pex_hash = self.pex_hash
-            if pex_hash:
-                tmp_root = os.path.realpath(
-                    os.path.join(tempfile.gettempdir(), "pex_root_unwriteable", pex_hash)
-                )
-                touch(os.path.join(tmp_root, ".write-test"))
-            else:
-                tmp_root = os.path.realpath(safe_mkdtemp())
+            tmp_root = os.path.realpath(safe_mkdtemp())
             pex_warnings.warn(
                 "PEX_ROOT is configured as {pex_root} but that path is un-writeable, "
                 "falling back to a temporary PEX_ROOT of {tmp_root} which will hurt "

pex/variables.py

@@ -171,7 +171,17 @@ def _default_pex_root():
     # third party import lifecycle events.
     from pex.cache import root as cache_root
 
-    return cache_root.path(expand_user=True)
+    pex_root = cache_root.path(expand_user=True)
+    if not can_write_dir(pex_root):
+        tmp_root = os.path.realpath(safe_mkdtemp())
+        pex_warnings.warn(
+            "The default PEX_ROOT is {pex_root} but that path is un-writeable, falling back to a "
+            "temporary PEX_ROOT of {tmp_root} which will hurt performance.".format(
+                pex_root=pex_root, tmp_root=tmp_root
+            )
+        )
+        pex_root = tmp_root
+    return pex_root
 
 
 class Variables(object):

tests/integration/test_issue_1598.py

@@ -23,12 +23,12 @@ def test_mount_respects_env(
     pex_root = os.path.join(home, rel_pex_root)
     os.makedirs(pex_root)
     os.chmod(pex_root, 0o555)
-    unwritable_pex_root_warning = "PEXWarning: PEX_ROOT is configured as {}".format(pex_root)
+    unwritable_pex_root_warning = "PEXWarning: The default PEX_ROOT is {}".format(pex_root)
 
     pex_file = os.path.join(str(tmpdir), "pex.pex")
 
     result = run_pex_command(
-        args=[pex_project_dir, "-o", pex_file], env=make_env(HOME=home, _PEX_DEBUG=1), quiet=True
+        args=[pex_project_dir, "-o", pex_file], env=make_env(HOME=home), quiet=True
     )
     result.assert_success()
 

tox.ini

@@ -60,8 +60,6 @@ passenv =
     _PEX_PEXPECT_TIMEOUT
     # This allows experimenting with Requires-Python metadata adjustment.
     _PEX_REQUIRES_PYTHON
-    # Allow debugging individual tests.
-    _PEX_DEBUG
     # This allows tests to detect they are running in CI.
     CI
     # These are to support directing test environments to the correct headers on OSX.