Mailing List Archive

https://github.com/python/cpython/commit/689ada79150f28b0053fa6c1fb646b75ab2cc200
commit: 689ada79150f28b0053fa6c1fb646b75ab2cc200
branch: main
author: Pablo Galindo Salgado <Pablogsal@gmail.com>
committer: pablogsal <Pablogsal@gmail.com>
date: 2024-04-10T20:09:25+01:00
summary:

gh-67224: Make linecache imports relative to improve startup speed (#117501)

files:
M Lib/linecache.py

diff --git a/Lib/linecache.py b/Lib/linecache.py
index b97999fc1dc909..d1113b108dc5e4 100644
--- a/Lib/linecache.py
+++ b/Lib/linecache.py
@@ -5,9 +5,6 @@
that name.
"""

-import sys
-import os
-
__all__ = ["getline", "clearcache", "checkcache", "lazycache"]


@@ -66,6 +63,11 @@ def checkcache(filename=None):
size, mtime, lines, fullname = entry
if mtime is None:
continue # no-op for files loaded via a __loader__
+ try:
+ # This import can fail if the interpreter is shutting down
+ import os
+ except ImportError:
+ return
try:
stat = os.stat(fullname)
except OSError:
@@ -76,6 +78,12 @@ def checkcache(filename=None):


def updatecache(filename, module_globals=None):
+ # These imports are not at top level because linecache is in the critical
+ # path of the interpreter startup and importing os and sys take a lot of time
+ # and slow down the startup sequence.
+ import os
+ import sys
+
"""Update a cache entry and return its list of lines.
If something's wrong, print a message, discard the cache entry,
and return an empty list."""

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