mergecopies: add logic to process incomplete data

We first combine incomplete copies on the two sides of the topological CA
into complete copies.
Any leftover incomplete copies are then combined with the incomplete
divergences to reconstruct divergences spanning over the topological CA.
Finally we promote any divergences falsely flagged as incomplete to full
divergences.

Right now, there is nothing generating incomplete copy/divergence data,
so this code does nothing. Changes to _checkcopies to populate these
dicts are coming later in this series.

mercurial/copies.py

@@ -289,6 +289,22 b' def _makegetfctx(ctx):'
         return fctx
     return util.lrucachefunc(makectx)
 
+def _combinecopies(copyfrom, copyto, finalcopy, diverge, incompletediverge):
+    """combine partial copy paths"""
+    remainder = {}
+    for f in copyfrom:
+        if f in copyto:
+            finalcopy[copyto[f]] = copyfrom[f]
+            del copyto[f]
+    for f in incompletediverge:
+        assert f not in diverge
+        ic = incompletediverge[f]
+        if ic[0] in copyto:
+            diverge[f] = [copyto[ic[0]], ic[1]]
+        else:
+            remainder[f] = ic
+    return remainder
+
 def mergecopies(repo, c1, c2, base):
     """
     Find moves and copies between context c1 and c2 that are relevant
@@ -360,14 +376,21 b' def mergecopies(repo, c1, c2, base):'
     # - diverge = record all diverges in this dict
     # - copy = record all non-divergent copies in this dict
     # - fullcopy = record all copies in this dict
+    # - incomplete = record non-divergent partial copies here
+    # - incompletediverge = record divergent partial copies here
     diverge = {} # divergence data is shared
+    incompletediverge  = {}
     data1 = {'copy': {},
              'fullcopy': {},
+             'incomplete': {},
              'diverge': diverge,
+             'incompletediverge': incompletediverge,
             }
     data2 = {'copy': {},
              'fullcopy': {},
+             'incomplete': {},
              'diverge': diverge,
+             'incompletediverge': incompletediverge,
             }
 
     # find interesting file sets from manifests
@@ -398,6 +421,13 b' def mergecopies(repo, c1, c2, base):'
     copy = dict(data1['copy'].items() + data2['copy'].items())
     fullcopy = dict(data1['fullcopy'].items() + data2['fullcopy'].items())
 
+    if dirtyc1:
+        _combinecopies(data2['incomplete'], data1['incomplete'], copy, diverge,
+                       incompletediverge)
+    else:
+        _combinecopies(data1['incomplete'], data2['incomplete'], copy, diverge,
+                       incompletediverge)
+
     renamedelete = {}
     renamedeleteset = set()
     divergeset = set()
@@ -416,13 +446,36 b' def mergecopies(repo, c1, c2, base):'
         repo.ui.debug("  unmatched files new in both:\n   %s\n"
                       % "\n   ".join(bothnew))
     bothdiverge = {}
-    bothdata = {'copy': {},
-                'fullcopy': {},
-                'diverge': bothdiverge,
-               }
+    bothincompletediverge = {}
+    both1 = {'copy': {},
+             'fullcopy': {},
+             'incomplete': {},
+             'diverge': bothdiverge,
+             'incompletediverge': bothincompletediverge
+            }
+    both2 = {'copy': {},
+             'fullcopy': {},
+             'incomplete': {},
+             'diverge': bothdiverge,
+             'incompletediverge': bothincompletediverge
+            }
     for f in bothnew:
-        _checkcopies(c1, f, m1, m2, base, tca, limit, bothdata)
-        _checkcopies(c2, f, m2, m1, base, tca, limit, bothdata)
+        _checkcopies(c1, f, m1, m2, base, tca, limit, both1)
+        _checkcopies(c2, f, m2, m1, base, tca, limit, both2)
+    if dirtyc1:
+        assert both2['incomplete'] == {}
+        remainder = _combinecopies({}, both1['incomplete'], copy, bothdiverge,
+                                   bothincompletediverge)
+    else:
+        assert both1['incomplete'] == {}
+        remainder = _combinecopies({}, both2['incomplete'], copy, bothdiverge,
+                                   bothincompletediverge)
+    for f in remainder:
+        assert f not in bothdiverge
+        ic = remainder[f]
+        if ic[0] in (m1 if dirtyc1 else m2):
+            # backed-out rename on one side, but watch out for deleted files
+            bothdiverge[f] = ic
     for of, fl in bothdiverge.items():
         if len(fl) == 2 and fl[0] == fl[1]:
             copy[fl[0]] = of # not actually divergent, just matching renames