transaction: quietly rollback if no other changes than temporary files

If no actual change have been made, we don't really need to roll them back. We
only have to cleanup some temporary files and it seems reasonable to do that
quietly.

This will help us to use the transaction in wider context¹ without impacting the
user experience.

[1] as in Python context managers that lives longer.

mercurial/transaction.py

@@ -691,13 +691,22 b' class transaction(util.transactional):'
         True if nothing, except temporary files has been writen on disk."""
         if entries:
             return False
-        if self._backupentries:
-            return False
+        for e in self._backupentries:
+            if e[1]:
+                return False
         return True
 
     def _do_quick_abort(self, entries):
         """(Silently) do a quick cleanup (see _can_quick_abort)"""
         assert self._can_quick_abort(entries)
+        tmp_files = [e for e in self._backupentries if not e[1]]
+        for vfs_id, old_path, tmp_path, xxx in tmp_files:
+            assert not old_path
+            vfs = self._vfsmap[vfs_id]
+            try:
+                vfs.unlink(tmp_path)
+            except FileNotFoundError:
+                pass
         if self._backupjournal:
             self._opener.unlink(self._backupjournal)
         if self._journal:

tests/test-bookmarks.t

@@ -1126,8 +1126,6 b' repositories visible to an external hook'
   $ hg add a
   $ hg commit -m '#0'
   $ hg --config hooks.pretxnclose="sh $TESTTMP/savepending.sh" bookmarks INVISIBLE
-  transaction abort!
-  rollback completed
   abort: pretxnclose hook exited with status 1
   [40]
   $ cp .hg/bookmarks.pending.saved .hg/bookmarks.pending
@@ -1159,8 +1157,6 b' repositories visible to an external hook'
      x  y                      2:db815d6d32e6
   @unrelated
   no bookmarks set
-  transaction abort!
-  rollback completed
   abort: pretxnclose hook exited with status 1
   [40]
 
@@ -1243,8 +1239,6 b' add hooks:'
 attempt to create on a default changeset
 
   $ hg bookmark -r 81dcce76aa0b NEW
-  transaction abort!
-  rollback completed
   abort: pretxnclose-bookmark.force-public hook exited with status 1
   [40]
 
@@ -1255,7 +1249,5 b' create on a public changeset'
 move to the other branch
 
   $ hg bookmark -f -r 125c9a1d6df6 NEW
-  transaction abort!
-  rollback completed
   abort: pretxnclose-bookmark.force-forward hook exited with status 1
   [40]

tests/test-phases.t

@@ -818,8 +818,6 b' repositories visible to an external hook'
   $ hg phase 6
   6: draft
   $ hg --config hooks.pretxnclose="sh $TESTTMP/savepending.sh" phase -f -s 6
-  transaction abort!
-  rollback completed
   abort: pretxnclose hook exited with status 1
   [40]
   $ cp .hg/store/phaseroots.pending.saved .hg/store/phaseroots.pending
@@ -841,8 +839,6 b' repositories visible to an external hook'
   7: secret
   @push-dest
   6: draft
-  transaction abort!
-  rollback completed
   abort: pretxnclose hook exited with status 1
   [40]
 
@@ -915,13 +911,9 b' Install a hook that prevent b3325c91a4d9'
 Try various actions. only the draft move should succeed
 
   $ hg phase --public b3325c91a4d9
-  transaction abort!
-  rollback completed
   abort: pretxnclose-phase.nopublish_D hook exited with status 1
   [40]
   $ hg phase --public a603bfb5a83e
-  transaction abort!
-  rollback completed
   abort: pretxnclose-phase.nopublish_D hook exited with status 1
   [40]
   $ hg phase --draft 17a481b3bccb
@@ -932,8 +924,6 b' Try various actions. only the draft move'
   test-hook-close-phase: a603bfb5a83e312131cebcd05353c217d4d21dde:  secret -> draft
   test-hook-close-phase: 17a481b3bccb796c0521ae97903d81c52bfee4af:  secret -> draft
   $ hg phase --public 17a481b3bccb
-  transaction abort!
-  rollback completed
   abort: pretxnclose-phase.nopublish_D hook exited with status 1
   [40]
 

tests/test-rebase-transaction.t

@@ -168,8 +168,6 b' rebase can then be continued'
   rebasing 1:112478962961 B "B"
   rebasing 3:26805aba1e60 C "C"
   rebasing 5:f585351a92f8 D tip "D"
-  transaction abort!
-  rollback completed
   abort: edit failed: false exited with status 1
   [250]
   $ hg tglog

tests/test-share-bookmarks.t

@@ -99,8 +99,6 b' Therefore, this test scenario ignores ch'
      bm2                       2:c2e0ac586386 (svfs !)
    * bm3                       2:c2e0ac586386
      bmX                       2:c2e0ac586386 (vfs !)
-  transaction abort!
-  rollback completed
   abort: pretxnclose hook exited with status 1
   [40]
   $ hg book bm1
@@ -124,8 +122,6 b' src), because (1) HG_PENDING refers only'
      bm2                       2:c2e0ac586386 (svfs !)
      bm3                       2:c2e0ac586386
    * bmX                       2:c2e0ac586386
-  transaction abort!
-  rollback completed
   abort: pretxnclose hook exited with status 1
   [40]
   $ hg book bm3

tests/test-split.t

@@ -156,8 +156,6 b' was always recording three commits, one '
   record change 3/3 to 'a'?
   (enter ? for help) [Ynesfdaq?] y
   
-  transaction abort!
-  rollback completed
   abort: edit failed: false exited with status 1
   [250]
   $ hg status