[3.14] gh-138775: fix handle python -m base64 stdin correct with EOF signal (GH-138776) (#141432)

miss-islington · yihong0618 · picnixz · web-flow · commit 83c3eae099c8 · 2025-11-12T00:12:57.000Z
gh-138775: fix handle `python -m base64` stdin correct with EOF signal (GH-138776) * fix: handle stdin correct with EOF single. * fix: flollow the comments when pipe stdin use buffer * Apply suggestions from code review * fix: apply review comments in Lib/base64.py * fix: address comments * Reword comment and NEWS entry. --------- (cherry picked from commit f5c2a41) Signed-off-by: yihong0618 <zouzou0208@gmail.com> Co-authored-by: yihong <zouzou0208@gmail.com> Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com> Co-authored-by: Peter Bierma <zintensitydev@gmail.com> Co-authored-by: Gregory P. Smith <greg@krypto.org>
diff --git a/Lib/base64.py b/Lib/base64.py
@@ -604,7 +604,14 @@ def main():
         with open(args[0], 'rb') as f:
             func(f, sys.stdout.buffer)
     else:
-        func(sys.stdin.buffer, sys.stdout.buffer)
+        if sys.stdin.isatty():
+            # gh-138775: read terminal input data all at once to detect EOF
+            import io
+            data = sys.stdin.buffer.read()
+            buffer = io.BytesIO(data)
+        else:
+            buffer = sys.stdin.buffer
+        func(buffer, sys.stdout.buffer)
 
 
 if __name__ == '__main__':
diff --git a/Misc/NEWS.d/next/Library/2025-09-11-15-03-37.gh-issue-138775.w7rnSx.rst b/Misc/NEWS.d/next/Library/2025-09-11-15-03-37.gh-issue-138775.w7rnSx.rst
@@ -0,0 +1,2 @@
+Use of ``python -m`` with :mod:`base64` has been fixed to detect input from a
+terminal so that it properly notices EOF.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+Use of ``python -m`` with :mod:`base64` has been fixed to detect input from a
	`2`	`+terminal so that it properly notices EOF.`