effectflag: detect when description changed

Store in effect flag when the description changed between the predecessor and
its successors.

It can happens with "hg commit --amend -e", "hg amend -e" or "histedit".

Differential Revision: https://phab.mercurial-scm.org/D535

mercurial/obsutil.py

@@ -308,6 +308,8 b' def foreground(repo, nodes):'
 # logic around storing and using effect flags
 EFFECTFLAGFIELD = "ef1"
 
+DESCCHANGED = 1 << 0 # action changed the description
+
 def geteffectflag(relation):
     """ From an obs-marker relation, compute what changed between the
     predecessor and the successor.
@@ -316,6 +318,11 b' def geteffectflag(relation):'
 
     source = relation[0]
 
+    for changectx in relation[1]:
+        # Check if description has changed
+        if changectx.description() != source.description():
+            effects |= DESCCHANGED
+
     return effects
 
 def getobsoleted(repo, tr):

tests/test-obsmarkers-effectflag.t

@@ -29,7 +29,7 b' amend touching the description only'
 check result
 
   $ hg debugobsolete --rev .
-  471f378eab4c5e25f6c77f785b27c936efb22874 fdf9bde5129a28d4548fadd3f62b265cdd3b7a2e 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'amend', 'user': 'test'}
+  471f378eab4c5e25f6c77f785b27c936efb22874 fdf9bde5129a28d4548fadd3f62b265cdd3b7a2e 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '1', 'operation': 'amend', 'user': 'test'}
 
 amend touching the user only
 ----------------------------
@@ -106,7 +106,7 b' amend with multiple effect (desc and met'
 check result
 
   $ hg debugobsolete --rev .
-  fad47e5bd78e6aa4db1b5a0a1751bc12563655ff a94e0fd5f1c81d969381a76eb0d37ce499a44fae 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '0', 'operation': 'amend', 'user': 'test'}
+  fad47e5bd78e6aa4db1b5a0a1751bc12563655ff a94e0fd5f1c81d969381a76eb0d37ce499a44fae 0 (Thu Jan 01 00:00:00 1970 +0000) {'ef1': '1', 'operation': 'amend', 'user': 'test'}
 
 rebase not touching the diff
 ----------------------------