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| author | Benjamin Peterson <benjamin@python.org> | 2017-12-09 10:26:52 -0800 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2017-12-09 10:26:52 -0800 |
| commit | 42aa93b8ff2f7879282b06efc73a31ec7785e602 (patch) | |
| tree | 92ee301e1f487a7f5aa8ec78a36ebc50d21d6ec9 /Doc/using | |
| parent | 28d8d14013ade0657fed4673f5fa3c08eb2b1944 (diff) | |
| download | cpython-git-42aa93b8ff2f7879282b06efc73a31ec7785e602.tar.gz | |
closes bpo-31650: PEP 552 (Deterministic pycs) implementation (#4575)
Python now supports checking bytecode cache up-to-dateness with a hash of the
source contents rather than volatile source metadata. See the PEP for details.
While a fairly straightforward idea, quite a lot of code had to be modified due
to the pervasiveness of pyc implementation details in the codebase. Changes in
this commit include:
- The core changes to importlib to understand how to read, validate, and
regenerate hash-based pycs.
- Support for generating hash-based pycs in py_compile and compileall.
- Modifications to our siphash implementation to support passing a custom
key. We then expose it to importlib through _imp.
- Updates to all places in the interpreter, standard library, and tests that
manually generate or parse pyc files to grok the new format.
- Support in the interpreter command line code for long options like
--check-hash-based-pycs.
- Tests and documentation for all of the above.
Diffstat (limited to 'Doc/using')
| -rw-r--r-- | Doc/using/cmdline.rst | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst index d110ae3baf..716bc821b4 100644 --- a/Doc/using/cmdline.rst +++ b/Doc/using/cmdline.rst @@ -210,6 +210,20 @@ Miscellaneous options import of source modules. See also :envvar:`PYTHONDONTWRITEBYTECODE`. +.. cmdoption:: --check-hash-based-pycs default|always|never + + Control the validation behavior of hash-based ``.pyc`` files. See + :ref:`pyc-invalidation`. When set to ``default``, checked and unchecked + hash-based bytecode cache files are validated according to their default + semantics. When set to ``always``, all hash-based ``.pyc`` files, whether + checked or unchecked, are validated against their corresponding source + file. When set to ``never``, hash-based ``.pyc`` files are not validated + against their corresponding source files. + + The semantics of timestamp-based ``.pyc`` files are unaffected by this + option. + + .. cmdoption:: -d Turn on parser debugging output (for expert only, depending on compilation |