[Python-checkins] bpo-30637: Improve the docs of ast.parse regarding differences with compile() (GH-28459)

miss-islington webhook-mailer at python.org
Sun Sep 19 19:14:02 EDT 2021

commit: 41e2a31c13ba73e2c30e9bf0be9417fd17e8ace2
branch: 3.9
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2021-09-19T16:13:56-07:00

bpo-30637: Improve the docs of ast.parse regarding differences with compile() (GH-28459)

(cherry picked from commit e6d05a4092b4176a30d1d1596585df13c2ab676d)

Co-authored-by: Pablo Galindo Salgado <Pablogsal at gmail.com>

M Doc/library/ast.rst

diff --git a/Doc/library/ast.rst b/Doc/library/ast.rst
index b8eecbda5e408..39a08416bad72 100644
--- a/Doc/library/ast.rst
+++ b/Doc/library/ast.rst
@@ -1549,6 +1549,19 @@ and classes for traversing abstract syntax trees:
    ``await`` as variable names.  The lowest supported version is
    ``(3, 4)``; the highest is ``sys.version_info[0:2]``.
+   If source contains a null character ('\0'), :exc:`ValueError` is raised.
+    .. warning::
+      Note that succesfully parsing souce code into an AST object doesn't
+      guarantee that the source code provided is valid Python code that can
+      be executed as the compilation step can raise further :exc:`SyntaxError`
+      exceptions. For instance, the source ``return 42`` generates a valid
+      AST node for a return statement, but it cannot be compiled alone (it needs
+      to be inside a function node).
+      In particular, :func:`ast.parse` won't do any scoping checks, which the
+      compilation step does.
    .. warning::
       It is possible to crash the Python interpreter with a
       sufficiently large/complex string due to stack depth limitations

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