diff -r ff17dff99295 -r f3c4edfd35e1 mercurial/help.py
--- a/mercurial/help.py	Tue Sep 27 14:46:34 2016 +0200
+++ b/mercurial/help.py	Tue Sep 13 22:58:12 2016 -0400
@@ -20,6 +20,7 @@
     encoding,
     error,
     extensions,
+    fancyopts,
     filemerge,
     fileset,
     minirst,
@@ -65,6 +66,7 @@
 def optrst(header, options, verbose):
     data = []
     multioccur = False
+    alllong = set(o[1] for o in options)
     for option in options:
         if len(option) == 5:
             shortopt, longopt, default, desc, optlabel = option
@@ -87,6 +89,16 @@
             multioccur = True
         elif (default is not None) and not isinstance(default, bool):
             lo += " %s" % optlabel
+        elif longopt not in fancyopts.nevernegate:
+            if longopt.startswith('no-'):
+                # This odd if statement guards against showing
+                # --no-commit and --commit on backout (as a practical
+                # example) as --[no-]commit in help.
+                if (longopt[3:]) not in alllong:
+                    lo = '--[no-]' + lo[5:]
+            else:
+                if ('no-' + longopt) not in alllong:
+                    lo = '--[no-]' + lo[2:]
 
         data.append((so, lo, desc))