From patchwork Wed Apr  1 19:09:37 2020
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Subject: D8338: hook: move stdio redirection to context manager
From: phabricator <phabricator@mercurial-scm.org>
X-Patchwork-Id: 45979
Message-Id: <30f591ab5affadecf68170176885acbc@localhost.localdomain>
To: Phabricator <phabricator@mercurial-scm.org>
Cc: mercurial-devel@mercurial-scm.org
Date: Wed, 1 Apr 2020 19:09:37 +0000

Closed by commit rHG3cbbfd0bfc17: hook: move stdio redirection to context manager (authored by indygreg).
This revision was automatically updated to reflect the committed changes.
This revision was not accepted when it landed; it landed in state "Needs Review".

REPOSITORY
  rHG Mercurial

CHANGES SINCE LAST UPDATE
  https://phab.mercurial-scm.org/D8338?vs=20911&id=20949

CHANGES SINCE LAST ACTION
  https://phab.mercurial-scm.org/D8338/new/

REVISION DETAIL
  https://phab.mercurial-scm.org/D8338

AFFECTED FILES
  mercurial/hook.py

CHANGE DETAILS




To: indygreg, #hg-reviewers, Alphare
Cc: mercurial-devel

diff --git a/mercurial/hook.py b/mercurial/hook.py
--- a/mercurial/hook.py
+++ b/mercurial/hook.py
@@ -7,6 +7,7 @@
 
 from __future__ import absolute_import
 
+import contextlib
 import os
 import sys
 
@@ -259,26 +260,45 @@
     return r
 
 
+@contextlib.contextmanager
+def redirect_stdio():
+    """Redirects stdout to stderr, if possible."""
+
+    oldstdout = -1
+    try:
+        if _redirect:
+            try:
+                stdoutno = procutil.stdout.fileno()
+                stderrno = procutil.stderr.fileno()
+                # temporarily redirect stdout to stderr, if possible
+                if stdoutno >= 0 and stderrno >= 0:
+                    procutil.stdout.flush()
+                    oldstdout = os.dup(stdoutno)
+                    os.dup2(stderrno, stdoutno)
+            except (OSError, AttributeError):
+                # files seem to be bogus, give up on redirecting (WSGI, etc)
+                pass
+
+        yield
+
+    finally:
+        # The stderr is fully buffered on Windows when connected to a pipe.
+        # A forcible flush is required to make small stderr data in the
+        # remote side available to the client immediately.
+        procutil.stderr.flush()
+
+        if _redirect and oldstdout >= 0:
+            procutil.stdout.flush()  # write hook output to stderr fd
+            os.dup2(oldstdout, stdoutno)
+            os.close(oldstdout)
+
+
 def runhooks(ui, repo, htype, hooks, throw=False, **args):
     args = pycompat.byteskwargs(args)
     res = {}
-    oldstdout = -1
 
-    try:
+    with redirect_stdio():
         for hname, cmd in hooks:
-            if oldstdout == -1 and _redirect:
-                try:
-                    stdoutno = procutil.stdout.fileno()
-                    stderrno = procutil.stderr.fileno()
-                    # temporarily redirect stdout to stderr, if possible
-                    if stdoutno >= 0 and stderrno >= 0:
-                        procutil.stdout.flush()
-                        oldstdout = os.dup(stdoutno)
-                        os.dup2(stderrno, stdoutno)
-                except (OSError, AttributeError):
-                    # files seem to be bogus, give up on redirecting (WSGI, etc)
-                    pass
-
             if cmd is _fromuntrusted:
                 if throw:
                     raise error.HookAbort(
@@ -312,15 +332,5 @@
                 raised = False
 
             res[hname] = r, raised
-    finally:
-        # The stderr is fully buffered on Windows when connected to a pipe.
-        # A forcible flush is required to make small stderr data in the
-        # remote side available to the client immediately.
-        procutil.stderr.flush()
-
-        if _redirect and oldstdout >= 0:
-            procutil.stdout.flush()  # write hook output to stderr fd
-            os.dup2(oldstdout, stdoutno)
-            os.close(oldstdout)
 
     return res