dispatch: catch KeyboardInterrupt more broadly

Because _runcatch() can run long operations in its exception handler,
it wasn't enough to catch KeyboardInterrupt at the same level. For
example, "hg unknown" will load all extension modules, so we could
easily make it crashed by Ctrl-C.

mercurial/dispatch.py

@@ -120,11 +120,18 b' def dispatch(req):'
     ret = None
     try:
         ret = _runcatch(req)
-        return ret
+    except KeyboardInterrupt:
+        try:
+            req.ui.warn(_("interrupted!\n"))
+        except IOError as inst:
+            if inst.errno != errno.EPIPE:
+                raise
+        ret = -1
     finally:
         duration = time.time() - starttime
         req.ui.log("commandfinish", "%s exited %s after %0.2f seconds\n",
                    msg, ret or 0, duration)
+    return ret
 
 def _runcatch(req):
     def catchterm(*args):
@@ -313,11 +320,7 b' def _runcatch(req):'
         else:
             ui.warn(_("abort: %s\n") % inst.strerror)
     except KeyboardInterrupt:
-        try:
-            ui.warn(_("interrupted!\n"))
-        except IOError as inst:
-            if inst.errno != errno.EPIPE:
-                raise
+        raise
     except MemoryError:
         ui.warn(_("abort: out of memory\n"))
     except SystemExit as inst: