diff hgext/fix.py @ 38967:a009589cd32a

fix: determine fixer tool failure by exit code instead of stderr

This seems like the more natural thing, and it probably should have been this
way to beign with. It is more flexible because it allows tools to emit
diagnostic information while also modifying a file. An example would be an
automatic code formatter that also prints any remaining lint issues.

Differential Revision: https://phab.mercurial-scm.org/D4158

--- a/hgext/fix.py	Thu Aug 09 13:13:09 2018 +0300
+++ b/hgext/fix.py	Tue Aug 07 21:15:27 2018 -0700
@@ -435,6 +435,9 @@
     starting with the file's content in the fixctx. Fixers that support line
     ranges will affect lines that have changed relative to any of the basectxs
     (i.e. they will only avoid lines that are common to all basectxs).
+
+    A fixer tool's stdout will become the file's new content if and only if it
+    exits with code zero.
     """
     newdata = fixctx[path].data()
     for fixername, fixer in fixers.iteritems():
@@ -454,8 +457,11 @@
             newerdata, stderr = proc.communicate(newdata)
             if stderr:
                 showstderr(ui, fixctx.rev(), fixername, stderr)
-            else:
+            if proc.returncode == 0:
                 newdata = newerdata
+            elif not stderr:
+                showstderr(ui, fixctx.rev(), fixername,
+                           _('exited with status %d\n') % (proc.returncode,))
     return newdata
 
 def showstderr(ui, rev, fixername, stderr):