.

wcfs/internal/xbtree/treediff.go

@@ -82,7 +82,7 @@ import (
 	"lab.nexedi.com/nexedi/wendelin.core/wcfs/internal/xzodb"
 )
 
-const traceDiff = false
+const traceDiff = true
 const debugDiff = false
 
 // ΔValue represents change in value.
@@ -481,6 +481,7 @@ func diffT(ctx context.Context, A, B *Tree, δZTC SetOid, trackSet PPTreeSubSet)
 		// this way, if later, the subtree will be recreated, that change won't be missed
 		δtrack.Del.AddPath(ABpath)
 		δtrack.Add.AddPath(ABpath)
+		// δtkeycov stays ø
 	}
 
 	// A|B == nil  -> artificial empty tree
@@ -532,6 +533,10 @@ func diffT(ctx context.Context, A, B *Tree, δZTC SetOid, trackSet PPTreeSubSet)
 		BtrackSet.AddPath(ABpath)
 	}
 
+	// δtkeycov will be = BAdd \ ADel
+	δtkeycovADel := &RangedKeySet{}
+	δtkeycovBAdd := &RangedKeySet{}
+
 	// phase 1: expand A top->down driven by δZTC.
 	// by default a node contributes to δ-
 	// a node ac does not contribute to δ- and can be skipped, if:
@@ -554,9 +559,11 @@ func diffT(ctx context.Context, A, B *Tree, δZTC SetOid, trackSet PPTreeSubSet)
 			δA, err := diffB(ctx, a, nil);  /*X*/if err != nil { return nil,nil,nil, err }
 			err = δMerge(δ, δA);		/*X*/if err != nil { return nil,nil,nil, err }
 			δtrack.Del.AddPath(ra.Path())
+			ar := KeyRange{ra.lo, ra.hi_}
+			δtkeycovADel.AddRange(ar)
 
 			// Bkqueue <- ra.range
-			Bktodo(KeyRange{ra.lo, ra.hi_})
+			Bktodo(ar)
 			ra.done = true
 
 		case *Tree:
@@ -625,6 +632,7 @@ func diffT(ctx context.Context, A, B *Tree, δZTC SetOid, trackSet PPTreeSubSet)
 							if nc := at.nchild; nc != 0 {
 								δtrack.δnchildNonLeafs[acOid] = nc
 							}
+							// XXX δtkeycov
 						}
 
 						continue
@@ -680,9 +688,10 @@ func diffT(ctx context.Context, A, B *Tree, δZTC SetOid, trackSet PPTreeSubSet)
 					// δ <- δB
 					err = δMerge(δ, δB);	/*X*/if err != nil { return nil,nil,nil, err }
 					δtrack.Add.AddPath(b.Path())
+					br := KeyRange{b.lo, b.hi_}
+					δtkeycovBAdd.AddRange(br)
 
 					// Akqueue <- δB
-					br := KeyRange{b.lo, b.hi_}
 					Bkdone.AddRange(br)
 					Aktodo(br)
 
@@ -717,9 +726,10 @@ func diffT(ctx context.Context, A, B *Tree, δZTC SetOid, trackSet PPTreeSubSet)
 					// δ <- δA
 					err = δMerge(δ, δA);	/*X*/if err != nil { return nil,nil,nil, err }
 					δtrack.Del.AddPath(a.Path())
+					ar := KeyRange{a.lo, a.hi_}
+					δtkeycovADel.AddRange(ar)
 
 					// Bkqueue <- a.range
-					ar := KeyRange{a.lo, a.hi_}
 					Akdone.AddRange(ar)
 					Bktodo(ar)
 
@@ -736,6 +746,7 @@ func diffT(ctx context.Context, A, B *Tree, δZTC SetOid, trackSet PPTreeSubSet)
 		Akqueue.Clear()
 	}
 
+	δtkeycov = δtkeycovBAdd.Difference(δtkeycovADel)
 	return δ, δtrack, δtkeycov, nil
 }
 

wcfs/internal/xbtree/δbtail_test.go

@@ -835,11 +835,11 @@ func xverifyΔBTail_Update1(t *testing.T, subj string, db *zodb.DB, treeRoot zod
 		return
 	}
 
-	// assert δtkeyCov == δ(tkeyCov1, tkeyCov2)
-	δtkeyCovOK := tkeyCov2.Difference(tkeyCov1)
-	δtkeyCov := δTKeyCov.ByRoot[treeRoot]
-	if !δtkeyCov.Equal(δtkeyCovOK) {
-		badf("δtkeyCov wrong:\nhave: %s\nwant: %s", δtkeyCov, δtkeyCovOK)
+	// assert δtkeycov == δ(tkeyCov1, tkeyCov2)
+	δtkeycovOK := tkeyCov2.Difference(tkeyCov1)
+	δtkeycov := δTKeyCov.ByRoot[treeRoot]
+	if !δtkeycov.Equal(δtkeycovOK) {
+		badf("δtkeycov wrong:\nhave: %s\nwant: %s", δtkeycov, δtkeycovOK)
 	}