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global: use python3 in shebangs
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Authored by indygreg on Fri, Nov 6, 5:27 PM.

Details

Summary

Python 3 is the future. We want Python scripts to be using Python 3
by default.

This change updates all #!/usr/bin/env python shebangs to use
python3.

Does this mean all scripts use or require Python 3: no.

In the test environment, the PATH environment variable in tests is
updated to guarantee that the Python executable used to run
run-tests.py is used. Since test scripts all now use
#!/usr/bin/env python3, we had to update this code to install
a python3 symlink instead of python.

It is possible there are some random scripts now executed with the
incorrect Python interpreter in some contexts. However, I would argue
that this was a pre-existing bug: we should almost always be executing
new Python processes using the sys.executable from the originating
Python script, as python or python3 won't guarantee we'll use the
same interpreter.

Diff Detail

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rHG Mercurial
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Unit
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Event Timeline

indygreg created this revision.Fri, Nov 6, 5:27 PM

test-parseindex2.py fails for me with this patch:

@@ -0,0 +1,11 @@
+FAIL: testversiondetection (__main__.parseindex2tests)
+
+Traceback (most recent call last):
+  File "/usr/local/google/home/martinvonz/hg/tests/test-parseindex2.py", line 201, in testversiondetection
+    self.assertversionokay(1, makehex(major, minor, micro))
+  File "/usr/local/google/home/martinvonz/hg/tests/test-parseindex2.py", line 170, in assertversionokay
+    self.assertFalse(
+AssertionError: b'Traceback (most recent call last):\n  File "<string>", line 1, in <module>\nImportError: No module named parsers\n' is not false : FAILED: version test #1 with Python sys.version_info(major=3, minor=8, micro=5, releaselevel='final', serial=0) and patched sys.hexversion 50857216 ('0x3080500'):
+ Expected no stdout but got:
+-->'b'Traceback (most recent call last):\n  File "<string>", line 1, in <module>\nImportError: No module named parsers\n''
+

I've sent D9286 to fix that. That patch needs to go in before this one. I'll add it as a parent here in phabricator.

martinvonz accepted this revision.Tue, Nov 10, 12:01 AM
This revision is now accepted and ready to land.Tue, Nov 10, 12:01 AM
This revision was automatically updated to reflect the committed changes.

This causes problems on Windows (since python3 == python.exe)- for example, all test-check-* but one are skipped because hghave is failing, complaining python3 is missing. The only way I can think of to work around this is to use $PYTHON to run the scripts instead of directly executing them. Before I do that, is there some other simpler mechanism that I'm overlooking? I tried to add alias python3="py -3" to the script that gets generated when MSYSTEM is in the environment around run-tests.py:1760, but that didn't help (likely env doesn't know about it).

This causes problems on Windows (since python3 == python.exe)- for example, all test-check-* but one are skipped because hghave is failing, complaining python3 is missing. The only way I can think of to work around this is to use $PYTHON to run the scripts instead of directly executing them. Before I do that, is there some other simpler mechanism that I'm overlooking? I tried to add alias python3="py -3" to the script that gets generated when MSYSTEM is in the environment around run-tests.py:1760, but that didn't help (likely env doesn't know about it).

@indygreg I don't have any idea what to do about this (other than to roll back this patch). What do you think?