[PATCH] progress: display progress bar when HGPLAINEXCEPT contains "progress"

[Matt Anderson]

# HG changeset patch
# User Matt Anderson <andersonmat at fb.com>
# Date 1455751110 28800
#      Wed Feb 17 15:18:30 2016 -0800
# Node ID 2c42cd3739baaef3f756b3366c2885efa5b40575
# Parent  a036e1ae1fbe88ab99cb861ebfc2e4da7a3912ca
progress: display progress bar when HGPLAINEXCEPT contains "progress"

This patch changes "progress.shouldprint()" so a feature name is provided to
"ui.plain()" to determine if there is an exception specificed in HGPLAINEXCEPT
for the progress extension.

This will allow user-facing scripts to provide progress output while HGPLAIN
is enabled.

diff --git a/mercurial/help/environment.txt b/mercurial/help/environment.txt
--- a/mercurial/help/environment.txt
+++ b/mercurial/help/environment.txt
@@ -69,6 +69,8 @@
         Preserve internationalization.
     ``revsetalias``
         Don't remove revset aliases.
+    ``progress``
+        Don't hide progress output.
 
     Setting HGPLAINEXCEPT to anything (even an empty string) will
     enable plain mode.
diff --git a/mercurial/progress.py b/mercurial/progress.py
--- a/mercurial/progress.py
+++ b/mercurial/progress.py
@@ -18,7 +18,7 @@
     return ' '.join(s for s in args if s)
 
 def shouldprint(ui):
-    return not (ui.quiet or ui.plain()) and (
+    return not (ui.quiet or ui.plain('progress')) and (
         ui._isatty(sys.stderr) or ui.configbool('progress', 'assume-tty'))
 
 def fmtremaining(seconds):
diff --git a/tests/test-progress.t b/tests/test-progress.t
--- a/tests/test-progress.t
+++ b/tests/test-progress.t
@@ -79,6 +79,13 @@
 no progress with --quiet
   $ hg -y loop 3 --quiet
 
+test plain mode exception
+  $ export HGPLAINEXCEPT=progress
+  $ hg -y loop 1
+  \r (no-eol) (esc)
+  loop [                                                ] 0/1\r (no-eol) (esc)
+                                                              \r (no-eol) (esc)
+
 test nested short-lived topics (which shouldn't display with nestdelay):
 
   $ hg -y loop 3 --nested