[3.13] Support the "pager" binary in _pyrepl (GH-122878) (#124242)

miss-islington · stefanor · Yhg1s · web-flow · commit 9e218afc8591 · 2024-10-07T23:45:43.000+02:00
Support the "pager" binary in _pyrepl (GH-122878) Debian (and derivatives) provide a /usr/bin/pager binary, managed by the alternatives system, that always points to an available pager utility. Allow _pyrepl to use it, to follow system policy. This is a very trivial change, from a patch that Debian has been carrying since 2.7 era. Seems appropriate to upstream. https://bugs.debian.org/799555 (cherry picked from commit 426569e) Co-authored-by: Stefano Rivera <stefano@rivera.za.net> Co-authored-by: T. Wouters <thomas@python.org>
diff --git a/Lib/_pyrepl/pager.py b/Lib/_pyrepl/pager.py
@@ -36,6 +36,8 @@ def get_pager() -> Pager:
         return plain_pager
     if sys.platform == 'win32':
         return lambda text, title='': tempfile_pager(plain(text), 'more <')
+    if hasattr(os, 'system') and os.system('(pager) 2>/dev/null') == 0:
+        return lambda text, title='': pipe_pager(text, 'pager', title)
     if hasattr(os, 'system') and os.system('(less) 2>/dev/null') == 0:
         return lambda text, title='': pipe_pager(text, 'less', title)
 
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2024-09-19-13-17-31.gh-issue-122878.4iFpsB.rst b/Misc/NEWS.d/next/Core_and_Builtins/2024-09-19-13-17-31.gh-issue-122878.4iFpsB.rst
@@ -0,0 +1 @@
+Use the ``pager`` binary, if available (e.g. on Debian and derivatives), to display REPL ``help()``.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+Use the ``pager`` binary, if available (e.g. on Debian and derivatives), to display REPL ``help()``.