X rebuild: tests: Don't recompute trackSet(keys1R2) several times

68s -> 63s

wcfs/internal/xbtree/pptreesubset.go

@@ -363,12 +363,12 @@ func (S PPTreeSubSet) verify() {
 	}()
 
 	// recompute {} oid -> children  and verify .nchild against it
-	children := map[zodb.Oid]SetOid{}
+	children := make(map[zodb.Oid]SetOid, len(S))
 	for oid, t := range S {
 		if t.parent != zodb.InvalidOid {
 			cc, ok := children[t.parent]
 			if !ok {
-				cc = SetOid{}
+				cc = make(SetOid, 1)
 				children[t.parent] = cc
 			}
 			cc.Add(oid)

wcfs/internal/xbtree/δbtail_test.go

@@ -1001,6 +1001,9 @@ func xverifyΔBTail_rebuild(t *testing.T, db *zodb.DB, treeRoot zodb.Oid, t0, t1
 				}
 			}
 
+			Tkeys1   := t1.xkv.trackSet(keys1)
+			Tkeys1_0 := t1.xkv.trackSet(keys1_0)
+
 			t.Run(fmt.Sprintf(" T%s;R", keys1), func(t *testing.T) {
 				δbtail := NewΔBtail(t0.at, db)
 
@@ -1016,10 +1019,10 @@ func xverifyΔBTail_rebuild(t *testing.T, db *zodb.DB, treeRoot zodb.Oid, t0, t1
 					// after Track(keys1)
 					keys1,
 					/*trackSet=*/ ø,
-					/*trackNew=*/ t1.xkv.trackSet(keys1),
+					/*trackNew=*/ Tkeys1,
 
 					// after rebuild
-					/*trackSet=*/ t1.xkv.trackSet(keys1_0),
+					/*trackSet=*/ Tkeys1_0,
 					/*vδT=*/ δkv1_1)
 
 				t.Run((" →" + t2.tree), func(t *testing.T) {
@@ -1048,8 +1051,10 @@ func xverifyΔBTail_rebuild(t *testing.T, db *zodb.DB, treeRoot zodb.Oid, t0, t1
 						}
 					}
 
+					Tkeys1R2  := t2.xkv.trackSet(keys1R2)
+
 					xverifyΔBTail_rebuild_U(t, δbtail, treeRoot, t1, t2, xat,
-						/*trackSet=*/t2.xkv.trackSet(keys1R2),
+						/*trackSet=*/ Tkeys1R2,
 						/*vδT=*/ δkv1_k1R2, δkv2_k1R2)
 
 					// tRestKeys2 = tAllKeys - keys1
@@ -1072,6 +1077,8 @@ func xverifyΔBTail_rebuild(t *testing.T, db *zodb.DB, treeRoot zodb.Oid, t0, t1
 							keys12R2 = keys12R2_
 						}
 
+						Tkeys2    := t2.xkv.trackSet(keys2)
+						Tkeys12R2 := t2.xkv.trackSet(keys12R2)
 /*
 						fmt.Printf("\n\n\nKKK\nkeys1=%s  keys2=%s\n", keys1, keys2)
 						fmt.Printf("keys1R2:  %s\n", keys1R2)
@@ -1082,10 +1089,9 @@ func xverifyΔBTail_rebuild(t *testing.T, db *zodb.DB, treeRoot zodb.Oid, t0, t1
 						fmt.Printf("t2.xkv: %v\n", t2.xkv)
 						fmt.Printf("kadj21: %v\n", kadj21)
 						fmt.Printf("kadj12: %v\n", kadj12)
-						fmt.Printf("t2.xkv.trackSet(keys2)   -> %s\n", t2.xkv.trackSet(keys2))
-						fmt.Printf("t2.xkv.trackSet(keys1R2) -> %s\n", t2.xkv.trackSet(keys1R2))
-						fmt.Printf("t2.xkv.trackSet(keys2) \\ t2.xkv.trackSet(keys1R2)  -> %s\n",
-							t2.xkv.trackSet(keys2).Difference(t2.xkv.trackSet(keys1R2)))
+						fmt.Printf("Tkeys2   -> %s\n", Tkeys2)
+						fmt.Printf("Tkeys1R2 -> %s\n", Tkeys1R2)
+						fmt.Printf("Tkeys2 \\ Tkeys1R2  -> %s\n", Tkeys2.Difference(Tkeys1R2))
 						fmt.Printf("\n\n\n")
 */
 
@@ -1110,14 +1116,14 @@ func xverifyΔBTail_rebuild(t *testing.T, db *zodb.DB, treeRoot zodb.Oid, t0, t1
 							xverifyΔBTail_rebuild_TR(t, δbtail_, t2, treeRoot, xat,
 								// after Track(keys2)
 								keys2,
-								/*trackSet*/ t2.xkv.trackSet(keys1R2),
-								/*trackNew*/ t2.xkv.trackSet(keys2).Difference(
+								/*trackSet*/ Tkeys1R2,
+								/*trackNew*/ Tkeys2.Difference(
 									// trackNew should not cover ranges that are
 									// already in trackSet
-									t2.xkv.trackSet(keys1R2)),
+									Tkeys1R2),
 
 								// after rebuild
-								/* trackSet=*/ t2.xkv.trackSet(keys12R2),
+								/* trackSet=*/ Tkeys12R2,
 								/*vδT=*/ δkv1_k12R2, δkv2_k12R2)
 						//})
 					}