Patchwork [v4] histedit: use one editor when multiple folds happen in a row (issue3524) (BC)

diff --git a/hgext/histedit.py b/hgext/histedit.py
--- a/hgext/histedit.py
+++ b/hgext/histedit.py
@@ -557,8 +557,21 @@  class fold(histeditaction):
                                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 @@  class fold(histeditaction):
         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 @@  class fold(histeditaction):
             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 @@  actiontable = {'p': pick,
                'edit': edit,
                'f': fold,
                'fold': fold,
+               '_multifold': _multifold,
                'r': rollup,
                'roll': rollup,
                'd': drop,
@@ -850,6 +879,14 @@  def _histedit(ui, repo, state, *freeargs
                                         '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 @@  def verifyrules(rules, repo, ctxs):
             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
diff --git a/tests/test-histedit-fold.t b/tests/test-histedit-fold.t
--- a/tests/test-histedit-fold.t
+++ b/tests/test-histedit-fold.t
@@ -509,4 +509,64 @@  into the hook command.
   $ hg add amended.txt
   $ hg ci -q --config extensions.largefiles= --amend -I amended.txt
 
+Test that folding multiple changes in a row doesn't show multiple
+editors.
+
+  $ echo foo >> foo
+  $ hg add foo
+  $ hg ci -m foo1
+  $ echo foo >> foo
+  $ hg ci -m foo2
+  $ echo foo >> foo
+  $ hg ci -m foo3
+  $ hg logt
+  4:21679ff7675c foo3
+  3:b7389cc4d66e foo2
+  2:0e01aeef5fa8 foo1
+  1:578c7455730c a
+  0:79b99e9c8e49 b
+  $ cat > $TESTTMP/editor.sh <<EOF
+  > echo ran editor >> $TESTTMP/editorlog.txt
+  > cat \$1 >> $TESTTMP/editorlog.txt
+  > echo END >> $TESTTMP/editorlog.txt
+  > echo merged foos > \$1
+  > EOF
+  $ HGEDITOR="sh $TESTTMP/editor.sh" hg histedit 1 --commands - 2>&1 <<EOF | fixbundle
+  > pick 578c7455730c 1 a
+  > pick 0e01aeef5fa8 2 foo1
+  > fold b7389cc4d66e 3 foo2
+  > fold 21679ff7675c 4 foo3
+  > EOF
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  reverting foo
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  merging foo
+  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg logt
+  2:e8bedbda72c1 merged foos
+  1:578c7455730c a
+  0:79b99e9c8e49 b
+Editor should have run only once
+  $ cat $TESTTMP/editorlog.txt
+  ran editor
+  foo1
+  ***
+  foo2
+  ***
+  foo3
+  
+  
+  
+  HG: Enter commit message.  Lines beginning with 'HG:' are removed.
+  HG: Leave message empty to abort commit.
+  HG: --
+  HG: user: test
+  HG: branch 'default'
+  HG: added foo
+  END
+
   $ cd ..