bpo-34022: Stop forcing of hash-based invalidation with SOURCE_DATE_EPOCH (GH-9607)

Unconditional forcing of ``CHECKED_HASH`` invalidation was introduced in
3.7.0 in bpo-29708.  The change is bad, as it unconditionally overrides
*invalidation_mode*, even if it was passed as an explicit argument to
``py_compile.compile()`` or ``compileall``.  An environment variable
should *never* override an explicit argument to a library function.
That change leads to multiple test failures if the ``SOURCE_DATE_EPOCH``
environment variable is set.

This changes ``py_compile.compile()`` to only look at
``SOURCE_DATE_EPOCH`` if no explicit *invalidation_mode* was specified.
I also made various relevant tests run with explicit control over the
value of ``SOURCE_DATE_EPOCH``.

While looking at this, I noticed that ``zipimport`` does not work
with hash-based .pycs _at all_, though I left the fixes for
subsequent commits.

1 files changed, 15 insertions, 0 deletions

diff --git a/Lib/test/test_importlib/source/test_file_loader.py b/Lib/test/test_importlib/source/test_file_loader.py
index c70c5eb..3ffb2aa 100644
--- a/Lib/test/test_importlib/source/test_file_loader.py
+++ b/Lib/test/test_importlib/source/test_file_loader.py
@@ -19,6 +19,9 @@ import warnings
 
 from test.support import make_legacy_pyc, unload
 
+from test.test_py_compile import without_source_date_epoch
+from test.test_py_compile import SourceDateEpochTestMeta
+
 
 class SimpleTest(abc.LoaderTests):
 
@@ -359,6 +362,17 @@ class SimpleTest(abc.LoaderTests):
                     abc=importlib_abc, util=importlib_util)
 
 
+class SourceDateEpochTestMeta(SourceDateEpochTestMeta,
+                              type(Source_SimpleTest)):
+    pass
+
+
+class SourceDateEpoch_SimpleTest(Source_SimpleTest,
+                                 metaclass=SourceDateEpochTestMeta,
+                                 source_date_epoch=True):
+    pass
+
+
 class BadBytecodeTest:
 
     def import_(self, file, module_name):
@@ -617,6 +631,7 @@ class SourceLoaderBadBytecodeTest:
 
     # [bad timestamp]
     @util.writes_bytecode_files
+    @without_source_date_epoch
     def test_old_timestamp(self):
         # When the timestamp is older than the source, bytecode should be
         # regenerated.