diff hgext/histedit.py @ 26246:bf81b696b8f4

histedit: use one editor when multiple folds happen in a row (issue3524) (BC)

This was the first ever feature request for histedit, originally filed
back on April 4, 2009. Finally fixed.

In the future we'll probably want to make it possible for other
preprocessing steps to be added to the list, but for now we're
skipping that because it's unclear what the API should look like
without a proposed consumer.

--- a/hgext/histedit.py	Mon Sep 14 18:41:09 2015 +0800
+++ b/hgext/histedit.py	Thu Aug 27 14:46:26 2015 -0400
@@ -557,8 +557,21 @@
                                middlecommits)
 
     def skipprompt(self):
+        """Returns true if the rule should skip the message editor.
+
+        For example, 'fold' wants to show an editor, but 'rollup'
+        doesn't want to.
+        """
         return False
 
+    def mergedescs(self):
+        """Returns true if the rule should merge messages of multiple changes.
+
+        This exists mainly so that 'rollup' rules can be a subclass of
+        'fold'.
+        """
+        return True
+
     def finishfold(self, ui, repo, ctx, oldctx, newnode, internalchanges):
         parent = ctx.parents()[0].node()
         hg.update(repo, parent)
@@ -566,7 +579,7 @@
         commitopts = {}
         commitopts['user'] = ctx.user()
         # commit message
-        if self.skipprompt():
+        if not self.mergedescs():
             newmessage = ctx.description()
         else:
             newmessage = '\n***\n'.join(
@@ -601,7 +614,22 @@
             replacements.append((ich, (n,)))
         return repo[n], replacements
 
+class _multifold(fold):
+    """fold subclass used for when multiple folds happen in a row
+
+    We only want to fire the editor for the folded message once when
+    (say) four changes are folded down into a single change. This is
+    similar to rollup, but we should preserve both messages so that
+    when the last fold operation runs we can show the user all the
+    commit messages in their editor.
+    """
+    def skipprompt(self):
+        return True
+
 class rollup(fold):
+    def mergedescs(self):
+        return False
+
     def skipprompt(self):
         return True
 
@@ -644,6 +672,7 @@
                'edit': edit,
                'f': fold,
                'fold': fold,
+               '_multifold': _multifold,
                'r': rollup,
                'roll': rollup,
                'd': drop,
@@ -850,6 +879,14 @@
                                         'histedit')
         state.backupfile = backupfile
 
+    # preprocess rules so that we can hide inner folds from the user
+    # and only show one editor
+    rules = state.rules[:]
+    for idx, ((action, ha), (nextact, unused)) in enumerate(
+            zip(rules, rules[1:] + [(None, None)])):
+        if action == 'fold' and nextact == 'fold':
+            state.rules[idx] = '_multifold', ha
+
     while state.rules:
         state.write()
         action, ha = state.rules.pop(0)
@@ -995,7 +1032,7 @@
             raise util.Abort(_('duplicated command for changeset %s') %
                     ha[:12])
         seen.add(ha)
-        if action not in actiontable:
+        if action not in actiontable or action.startswith('_'):
             raise util.Abort(_('unknown action "%s"') % action)
         parsed.append([action, ha])
     missing = sorted(expected - seen)  # sort to stabilize output