commit: tell user what to do with .hg/last-message.txt

I have always assumed that the message will be reused by the next `hg
commit`, but it seems it's just silently dropped on the next
commit. Let's try to be more helpful by telling the user that they
have to manually tell hg to reuse it.

The file will still be lost if the user runs some other operation in
between (like a non-in-memory rebase). That will be fixed once we've
switched all operations to be in-memory :)

I didn't include `$(hg root)/` in the path in the message to the user
because that would have made the message too long. Hopefully the user
will figure that part out themselves.

Differential Revision: https://phab.mercurial-scm.org/D8463

mercurial/localrepo.py

@@ -3016,6 +3016,12 b' class localrepository(object):'
                     self.ui.write(
                         _(b'note: commit message saved in %s\n') % msgfn
                     )
+                    self.ui.write(
+                        _(
+                            b"note: use 'hg commit --logfile "
+                            b".hg/last-message.txt --edit' to reuse it\n"
+                        )
+                    )
                 raise
 
         def commithook(unused_success):

tests/test-histedit-edit.t

@@ -373,6 +373,7 b' check saving last-message.txt, at first'
   transaction abort!
   rollback completed
   note: commit message saved in .hg/last-message.txt
+  note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
   abort: pretxncommit.unexpectedabort hook exited with status 1
   [255]
   $ cat .hg/last-message.txt
@@ -397,6 +398,7 b' action)'
   transaction abort!
   rollback completed
   note: commit message saved in .hg/last-message.txt
+  note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
   abort: pretxncommit.unexpectedabort hook exited with status 1
   [255]
 

tests/test-mq-qfold.t

@@ -230,6 +230,7 b" and that combination of '--edit' and '--"
   HG: changed a
   ====
   note: commit message saved in .hg/last-message.txt
+  note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
   transaction abort!
   rollback completed
   qrefresh interrupted while patch was popped! (revert --all, qpush to recover)

tests/test-mq-qnew.t

@@ -308,6 +308,7 b' Test saving last-message.txt'
   transaction abort!
   rollback completed
   note: commit message saved in .hg/last-message.txt
+  note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
   abort: pretxncommit.unexpectedabort hook exited with status 1
   [255]
   $ cat .hg/last-message.txt

tests/test-mq-qrefresh-replace-log-message.t

@@ -186,6 +186,7 b' Test saving last-message.txt:'
   HG: added file2
   ====
   note: commit message saved in .hg/last-message.txt
+  note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
   transaction abort!
   rollback completed
   qrefresh interrupted while patch was popped! (revert --all, qpush to recover)
@@ -229,6 +230,7 b' external process'
   A file2
   ====
   note: commit message saved in .hg/last-message.txt
+  note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
   transaction abort!
   rollback completed
   qrefresh interrupted while patch was popped! (revert --all, qpush to recover)

tests/test-rollback.t

@@ -116,6 +116,7 b' same thing, but run $EDITOR'
   transaction abort!
   rollback completed
   note: commit message saved in .hg/last-message.txt
+  note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
   abort: pretxncommit hook exited with status * (glob)
   [255]
   $ cat .hg/last-message.txt

tests/test-tag.t

@@ -323,6 +323,7 b" regardless of '--message')"
   transaction abort!
   rollback completed
   note: commit message saved in .hg/last-message.txt
+  note: use 'hg commit --logfile .hg/last-message.txt --edit' to reuse it
   abort: pretxncommit.unexpectedabort hook exited with status 1
   [255]
   $ cat .hg/last-message.txt