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.
diff --git a/Python/clinic/import.c.h b/Python/clinic/import.c.h
index ddd694f..1955e50 100644
--- a/Python/clinic/import.c.h
+++ b/Python/clinic/import.c.h
@@ -354,6 +354,41 @@
return return_value;
}
+PyDoc_STRVAR(_imp_source_hash__doc__,
+"source_hash($module, /, key, source)\n"
+"--\n"
+"\n");
+
+#define _IMP_SOURCE_HASH_METHODDEF \
+ {"source_hash", (PyCFunction)_imp_source_hash, METH_FASTCALL|METH_KEYWORDS, _imp_source_hash__doc__},
+
+static PyObject *
+_imp_source_hash_impl(PyObject *module, long key, Py_buffer *source);
+
+static PyObject *
+_imp_source_hash(PyObject *module, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
+{
+ PyObject *return_value = NULL;
+ static const char * const _keywords[] = {"key", "source", NULL};
+ static _PyArg_Parser _parser = {"ly*:source_hash", _keywords, 0};
+ long key;
+ Py_buffer source = {NULL, NULL};
+
+ if (!_PyArg_ParseStackAndKeywords(args, nargs, kwnames, &_parser,
+ &key, &source)) {
+ goto exit;
+ }
+ return_value = _imp_source_hash_impl(module, key, &source);
+
+exit:
+ /* Cleanup for source */
+ if (source.obj) {
+ PyBuffer_Release(&source);
+ }
+
+ return return_value;
+}
+
#ifndef _IMP_CREATE_DYNAMIC_METHODDEF
#define _IMP_CREATE_DYNAMIC_METHODDEF
#endif /* !defined(_IMP_CREATE_DYNAMIC_METHODDEF) */
@@ -361,4 +396,4 @@
#ifndef _IMP_EXEC_DYNAMIC_METHODDEF
#define _IMP_EXEC_DYNAMIC_METHODDEF
#endif /* !defined(_IMP_EXEC_DYNAMIC_METHODDEF) */
-/*[clinic end generated code: output=d068dd493e513604 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=e8b2c0b0d0a75da8 input=a9049054013a1b77]*/