histedit: modify rollup to discard date from the rollup commit (issue4820)

This change adjusts and documents the new behaviour of 'roll'. It now fits nicely
with the behaviour of 'commit --amend' and the 'edit' action, by discarding the
date as well as the commit message of the second commit. Previously it used the
later date, like 'fold', but this often wasn't desirable, for example, in the
common use case of using 'roll' to add forgotten changes to a changeset
(because 'hg add' was previously forgotten or not all changes were identified
while using 'hg record').

hgext/histedit.py

@@ -36,7 +36,7 b' file open in your editor::'
  #  p, pick = use commit
  #  e, edit = use commit, but stop for amending
  #  f, fold = use commit, but combine it with the one above
- #  r, roll = like fold, but discard this commit's description
+ #  r, roll = like fold, but discard this commit's description and date
  #  d, drop = remove commit from history
  #  m, mess = edit commit message without changing commit content
  #
@@ -58,7 +58,7 b' would reorganize the file to look like t'
  #  p, pick = use commit
  #  e, edit = use commit, but stop for amending
  #  f, fold = use commit, but combine it with the one above
- #  r, roll = like fold, but discard this commit's description
+ #  r, roll = like fold, but discard this commit's description and date
  #  d, drop = remove commit from history
  #  m, mess = edit commit message without changing commit content
  #
@@ -725,6 +725,15 b' class fold(histeditaction):'
         """
         return True
 
+    def firstdate(self):
+        """Returns true if the rule should preserve the date of the first
+        change.
+
+        This exists mainly so that 'rollup' rules can be a subclass of
+        'fold'.
+        """
+        return False
+
     def finishfold(self, ui, repo, ctx, oldctx, newnode, internalchanges):
         parent = ctx.parents()[0].node()
         repo.ui.pushbuffer()
@@ -743,7 +752,10 b' class fold(histeditaction):'
                 [oldctx.description()]) + '\n'
         commitopts['message'] = newmessage
         # date
-        commitopts['date'] = max(ctx.date(), oldctx.date())
+        if self.firstdate():
+            commitopts['date'] = ctx.date()
+        else:
+            commitopts['date'] = max(ctx.date(), oldctx.date())
         extra = ctx.extra().copy()
         # histedit_source
         # note: ctx is likely a temporary commit but that the best we can do
@@ -810,7 +822,7 b' class _multifold(fold):'
         return True
 
 @action(["roll", "r"],
-        _("like fold, but discard this commit's description"))
+        _("like fold, but discard this commit's description and date"))
 class rollup(fold):
     def mergedescs(self):
         return False
@@ -818,6 +830,9 b' class rollup(fold):'
     def skipprompt(self):
         return True
 
+    def firstdate(self):
+        return True
+
 @action(["drop", "d"],
         _('remove commit from history'))
 class drop(histeditaction):
@@ -887,7 +902,7 b' def histedit(ui, repo, *freeargs, **opts'
 
     - `fold` to combine it with the preceding changeset (using the later date)
 
-    - `roll` like fold, but discarding this commit's description
+    - `roll` like fold, but discarding this commit's description and date
 
     - `edit` to edit this changeset (preserving date)
 

tests/test-histedit-arguments.t

@@ -72,7 +72,7 b' Run a dummy edit to make sure we get tip'
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
 
 Run on a revision not ancestors of the current working directory.
@@ -308,7 +308,7 b' Test that trimming description using mul'
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
 
 Test --continue with --keep
@@ -544,7 +544,7 b" Check that 'roll' is selected by default"
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
 
   $ cd ..

tests/test-histedit-bookmark-motion.t

@@ -78,7 +78,7 b''
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
   $ hg histedit 1 --commands - --verbose << EOF | grep histedit
   > pick 177f92b77385 2 c
@@ -141,7 +141,7 b''
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
   $ hg histedit 1 --commands - --verbose << EOF | grep histedit
   > pick b346ab9a313d 1 c

tests/test-histedit-commute.t

@@ -72,7 +72,7 b' show the edit commands offered'
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
 
 edit the history
@@ -350,7 +350,7 b' Verify that revsetalias entries work wit'
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
 
 should also work if a commit message is missing

tests/test-histedit-edit.t

@@ -478,5 +478,5 b' Attempting to fold a change into a publi'
   #  p, fold = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #

tests/test-histedit-fold-non-commute.t

@@ -183,7 +183,7 b' manifest'
 
   $ cd ..
 
-Repeat test using "roll", not "fold". "roll" folds in changes but drops message
+Repeat test using "roll", not "fold". "roll" folds in changes but drops message and date
 
   $ initrepo r2
   $ cd r2
@@ -276,15 +276,15 b' just continue this time'
 
 log after edit
   $ hg log --graph
-  @  changeset:   5:162978f027fb
+  @  changeset:   5:b538bcb461be
   |  tag:         tip
   |  user:        test
   |  date:        Thu Jan 01 00:00:06 1970 +0000
   |  summary:     f
   |
-  o  changeset:   4:74e5e6c6c32f
+  o  changeset:   4:317e37cb6d66
   |  user:        test
-  |  date:        Thu Jan 01 00:00:07 1970 +0000
+  |  date:        Thu Jan 01 00:00:04 1970 +0000
   |  summary:     d
   |
   o  changeset:   3:092e4ce14829
@@ -324,13 +324,13 b' manifest'
 description is taken from rollup target commit
 
   $ hg log --debug --rev 4
-  changeset:   4:74e5e6c6c32fa39f0eeed43302fd48633ea5926f
+  changeset:   4:317e37cb6d66c1c84628c00e5bf4c8c292831951
   phase:       draft
   parent:      3:092e4ce14829f4974399ce4316d59f64ef0b6725
   parent:      -1:0000000000000000000000000000000000000000
   manifest:    4:b068a323d969f22af1296ec6a5ea9384cef437ac
   user:        test
-  date:        Thu Jan 01 00:00:07 1970 +0000
+  date:        Thu Jan 01 00:00:04 1970 +0000
   files:       d e
   extra:       branch=default
   extra:       histedit_source=ae78f4c9d74ffa4b6cb5045001c303fe9204e890,42abbb61bede6f4366fa1e74a664343e5d558a70

tests/test-histedit-fold.t

@@ -106,7 +106,7 b' check histedit_source, including that it'
   
   
 
-rollup will fold without preserving the folded commit's message
+rollup will fold without preserving the folded commit's message or date
 
   $ OLDHGEDITOR=$HGEDITOR
   $ HGEDITOR=false
@@ -121,11 +121,11 b' rollup will fold without preserving the '
 
 log after edit
   $ hg logt --graph
-  @  3:fb13f1f49340 d
+  @  3:bab801520cec d
   |
-  o  2:6d4bc3727566 f
+  o  2:58c8f2bfc151 f
   |
-  o  1:563995ddbe65 b
+  o  1:5d939c56c72e b
   |
   o  0:8580ff50825a a
   
@@ -133,13 +133,13 b' log after edit'
 description is taken from rollup target commit
 
   $ hg log --debug --rev 1
-  changeset:   1:563995ddbe650c0e6b0e1c1d75f0a197b61cec50
+  changeset:   1:5d939c56c72e77e29f5167696218e2131a40f5cf
   phase:       draft
   parent:      0:8580ff50825a50c8f716709acdf8de0deddcd6ab
   parent:      -1:0000000000000000000000000000000000000000
   manifest:    1:b5e112a3a8354e269b1524729f0918662d847c38
   user:        test
-  date:        Thu Jan 01 00:00:05 1970 +0000
+  date:        Thu Jan 01 00:00:02 1970 +0000
   files+:      b e
   extra:       branch=default
   extra:       histedit_source=97d72e5f12c7e84f85064aa72e5a297142c36ed9,505a591af19eed18f560af827b9e03d2076773dc
@@ -171,13 +171,13 b' check saving last-message.txt'
   > EOF
 
   $ rm -f .hg/last-message.txt
-  $ hg status --rev '6d4bc3727566^1::fb13f1f49340'
+  $ hg status --rev '58c8f2bfc151^1::bab801520cec'
   A c
   A d
   A f
-  $ HGEDITOR="sh $TESTTMP/editor.sh" hg histedit 6d4bc3727566 --commands - 2>&1 <<EOF
-  > pick 6d4bc3727566 f
-  > fold fb13f1f49340 d
+  $ HGEDITOR="sh $TESTTMP/editor.sh" hg histedit 58c8f2bfc151 --commands - 2>&1 <<EOF
+  > pick 58c8f2bfc151 f
+  > fold bab801520cec d
   > EOF
   allow non-folding commit
   ==== before editing

tests/test-histedit-obsolete.t

@@ -136,7 +136,7 b' Base setup for the rest of the testing'
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
   $ hg histedit 1 --commands - --verbose <<EOF | grep histedit
   > pick 177f92b77385 2 c

tests/test-histedit-outgoing.t

@@ -54,7 +54,7 b' show the edit commands offered by outgoi'
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
   $ cd ..
 
@@ -88,7 +88,7 b' show the error from unrelated repos'
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
   $ cd ..
 
@@ -114,7 +114,7 b' test sensitivity to branch in URL:'
   #  p, pick = use commit
   #  d, drop = remove commit from history
   #  f, fold = use commit, but combine it with the one above
-  #  r, roll = like fold, but discard this commit's description
+  #  r, roll = like fold, but discard this commit's description and date
   #
 
 test to check number of roots in outgoing revisions