[PATCH 2 of 2] extensions: suggest --config extensions.bad=! when bad fails

[timeless at mozdev.org]

# HG changeset patch
# User timeless at mozdev.org
# Date 1441928905 14400
#      Thu Sep 10 19:48:25 2015 -0400
# Node ID d7d94ed8a182092c2f667b915be972e9c1de9e0b
# Parent  cc7fc4b67ea0880faa4f8d823ba8fc348f71c0f9
extensions: suggest --config extensions.bad=! when bad fails

There are lots of ways for extensions to fail, so users should
be given a hint about how to deal with them, instead of being
left to scratch their heads.

diff --git a/mercurial/extensions.py b/mercurial/extensions.py
--- a/mercurial/extensions.py
+++ b/mercurial/extensions.py
@@ -119,11 +119,13 @@
             raise
         except Exception as inst:
             if path:
-                ui.warn(_("*** failed to import extension %s from %s: %s\n")
-                        % (name, path, inst))
+                ui.warn(_("*** failed to import extension %s from %s: %s\n"
+                          "(you can use '--config extensions.%s=!%s' to disable it)\n")
+                        % (name, path, inst, name, path))
             else:
-                ui.warn(_("*** failed to import extension %s: %s\n")
-                        % (name, inst))
+                ui.warn(_("*** failed to import extension %s: %s\n"
+                          "(you can use '--config extensions.%s=!' to disable it)\n")
+                        % (name, inst, name))
             ui.traceback()
 
     for name in _order[newindex:]:
diff --git a/tests/test-bad-extension.t b/tests/test-bad-extension.t
--- a/tests/test-bad-extension.t
+++ b/tests/test-bad-extension.t
@@ -11,15 +11,19 @@
 
   $ hg -q help help 2>&1 |grep extension
   *** failed to import extension badext from $TESTTMP/badext.py: bit bucket overflow
+  (you can use '--config extensions.badext=!$TESTTMP/badext.py' to disable it)
   *** failed to import extension badext2: No module named badext2
+  (you can use '--config extensions.badext2=!' to disable it)
 
 show traceback
 
   $ hg -q help help --traceback 2>&1 | egrep ' extension|^Exception|Traceback|ImportError'
   *** failed to import extension badext from $TESTTMP/badext.py: bit bucket overflow
+  (you can use '--config extensions.badext=!$TESTTMP/badext.py' to disable it)
   Traceback (most recent call last):
   Exception: bit bucket overflow
   *** failed to import extension badext2: No module named badext2
+  (you can use '--config extensions.badext2=!' to disable it)
   Traceback (most recent call last):
   ImportError: No module named badext2
 
@@ -30,11 +34,13 @@
   > | grep -v '^ ' \
   > | egrep 'extension..[^p]|^Exception|Traceback|ImportError|not import'
   *** failed to import extension badext from $TESTTMP/badext.py: bit bucket overflow
+  (you can use '--config extensions.badext=!$TESTTMP/badext.py' to disable it)
   Traceback (most recent call last):
   Exception: bit bucket overflow
   could not import hgext.badext2 (No module named badext2): trying badext2
   Traceback (most recent call last):
   ImportError: No module named badext2
   *** failed to import extension badext2: No module named badext2
+  (you can use '--config extensions.badext2=!' to disable it)
   Traceback (most recent call last):
   ImportError: No module named badext2
diff --git a/tests/test-qrecord.t b/tests/test-qrecord.t
--- a/tests/test-qrecord.t
+++ b/tests/test-qrecord.t
@@ -110,6 +110,7 @@
   $ echo "mq=nonexistent" >> $HGRCPATH
   $ hg help qrecord
   *** failed to import extension mq from nonexistent: [Errno *] * (glob)
+  (you can use '--config extensions.mq=!nonexistent' to disable it)
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