diff mercurial/copies.py @ 46563:c19c662097e1

copies: detect case when a merge decision overwrite previous data

We now detect and record when a merge case required special logic (eg: thing
that append during the merge, ambiguity leading to picking p1 data, etc) and we
explicitly mark the result as superseding the previous data.

This fixes the family of test we previously added.

Differential Revision: https://phab.mercurial-scm.org/D9613

--- a/mercurial/copies.py	Mon Dec 14 19:26:33 2020 +0100
+++ b/mercurial/copies.py	Sat Dec 12 19:35:08 2020 +0100
@@ -434,7 +434,11 @@
                     # potential filelog related behavior.
                     assert parent == 2
                     current_copies = _merge_copies_dict(
-                        newcopies, current_copies, isancestor, changes
+                        newcopies,
+                        current_copies,
+                        isancestor,
+                        changes,
+                        current_rev,
                     )
             all_copies[current_rev] = current_copies
 
@@ -456,7 +460,7 @@
 PICK_EITHER = 2
 
 
-def _merge_copies_dict(minor, major, isancestor, changes):
+def _merge_copies_dict(minor, major, isancestor, changes, current_merge):
     """merge two copies-mapping together, minor and major
 
     In case of conflict, value from "major" will be picked.
@@ -474,8 +478,15 @@
         if other is None:
             minor[dest] = value
         else:
-            pick = _compare_values(changes, isancestor, dest, other, value)
-            if pick == PICK_MAJOR:
+            pick, overwrite = _compare_values(
+                changes, isancestor, dest, other, value
+            )
+            if overwrite:
+                if pick == PICK_MAJOR:
+                    minor[dest] = (current_merge, value[1])
+                else:
+                    minor[dest] = (current_merge, other[1])
+            elif pick == PICK_MAJOR:
                 minor[dest] = value
     return minor
 
@@ -483,9 +494,10 @@
 def _compare_values(changes, isancestor, dest, minor, major):
     """compare two value within a _merge_copies_dict loop iteration
 
-    return pick
+    return (pick, overwrite).
 
     - pick is one of PICK_MINOR, PICK_MAJOR or PICK_EITHER
+    - overwrite is True if pick is a return of an ambiguity that needs resolution.
     """
     major_tt, major_value = major
     minor_tt, minor_value = minor
@@ -493,7 +505,7 @@
     if major_tt == minor_tt:
         # if it comes from the same revision it must be the same value
         assert major_value == minor_value
-        return PICK_EITHER
+        return PICK_EITHER, False
     elif (
         changes is not None
         and minor_value is not None
@@ -502,7 +514,7 @@
     ):
         # In this case, a deletion was reverted, the "alive" value overwrite
         # the deleted one.
-        return PICK_MINOR
+        return PICK_MINOR, True
     elif (
         changes is not None
         and major_value is not None
@@ -511,30 +523,30 @@
     ):
         # In this case, a deletion was reverted, the "alive" value overwrite
         # the deleted one.
-        return PICK_MAJOR
+        return PICK_MAJOR, True
     elif isancestor(minor_tt, major_tt):
         if changes is not None and dest in changes.merged:
             # change to dest happened on the branch without copy-source change,
             # so both source are valid and "major" wins.
-            return PICK_MAJOR
+            return PICK_MAJOR, True
         else:
-            return PICK_MAJOR
+            return PICK_MAJOR, False
     elif isancestor(major_tt, minor_tt):
         if changes is not None and dest in changes.merged:
             # change to dest happened on the branch without copy-source change,
             # so both source are valid and "major" wins.
-            return PICK_MAJOR
+            return PICK_MAJOR, True
         else:
-            return PICK_MINOR
+            return PICK_MINOR, False
     elif minor_value is None:
         # in case of conflict, the "alive" side wins.
-        return PICK_MAJOR
+        return PICK_MAJOR, True
     elif major_value is None:
         # in case of conflict, the "alive" side wins.
-        return PICK_MINOR
+        return PICK_MINOR, True
     else:
         # in case of conflict where both side are alive, major wins.
-        return PICK_MAJOR
+        return PICK_MAJOR, True
 
 
 def _revinfo_getter_extra(repo):