.

wcfs/internal/xbtree/δbtail.go

@@ -681,8 +681,6 @@ func vδTBuild1(atPrev zodb.Tid, δZ zodb.ΔRevEntry, trackNew blib.PPTreeSubSet
 //
 // δrevSet indicates set of new revisions created in vδT.
 // vδT is modified inplace.
-//
-// XXX test
 func vδTMergeInplace(pvδT *[]ΔTree, vδTnew []ΔTree) (δrevSet setTid) {
 	// TODO optimize to go through vδT and vδTnew sequentially if needed
 	δrevSet = setTid{}
@@ -699,9 +697,11 @@ func vδTMergeInplace(pvδT *[]ΔTree, vδTnew []ΔTree) (δrevSet setTid) {
 //
 // newRevEntry indicates whether δT.Rev was not there before in vδT.
 // vδT is modified inplace.
-//
-// XXX test
 func vδTMerge1Inplace(pvδT *[]ΔTree, δT ΔTree) (newRevEntry bool) {
+	if len(δT.KV) == 0 {
+		return false // δT has no change
+	}
+
 	vδT := *pvδT
 
 	l := len(vδT)

wcfs/internal/xbtree/δbtail_test.go

@@ -1357,6 +1357,96 @@ func TestΔBtailClone(t_ *testing.T) {
 	assertΔTtail(t.T, "klon @at1 after orig @at->@at2", δbklon, t1, t.Root(), δkv1_1)
 }
 
+// -------- vδTMerge --------
+
+func TestVδTMerge(t *testing.T) {
+	vδTMerge1 := func(vδT []ΔTree, δT ΔTree) (_ []ΔTree, newRevEntry bool) {
+		vδT = vδTClone(vδT)
+		newRevEntry = vδTMerge1Inplace(&vδT, δT)
+		return vδT, newRevEntry
+	}
+
+	vδTMerge := func(vδT, vδTnew []ΔTree) (_ []ΔTree, δrevSet setTid) {
+		vδT = vδTClone(vδT)
+		δrevSet = vδTMergeInplace(&vδT, vδTnew)
+		return vδT, δrevSet
+	}
+
+	assertMerge1 := func(vδT []ΔTree, δT ΔTree, newRevEntryOK bool, mergeOK []ΔTree) {
+		t.Helper()
+		merge, newRevEntry := vδTMerge1(vδT, δT)
+		if !(reflect.DeepEqual(merge, mergeOK) && newRevEntry == newRevEntryOK) {
+			t.Errorf("merge1 %v  +  %v:\nhave: %v  %t\nwant: %v  %t",
+				 vδT, δT, merge, newRevEntry, mergeOK, newRevEntryOK)
+		}
+	}
+
+	assertMerge := func(vδT, vδTnew []ΔTree, δrevSetOK setTid, mergeOK []ΔTree) {
+		t.Helper()
+		merge, δrevSet := vδTMerge(vδT, vδTnew)
+		if !(reflect.DeepEqual(merge, mergeOK) && δrevSet.Equal(δrevSetOK)) {
+			t.Errorf("merge  %v  +  %v:\nhave: %v  %v\nwant: %v  %v",
+				 vδT, vδTnew, merge, δrevSet, mergeOK, δrevSetOK)
+		}
+	}
+
+
+	// syntax sugar
+	type Δ = ΔTree
+	type δ = map[Key]ΔValue
+	v := func(vδT ...Δ) []Δ {
+		return vδT
+	}
+	r := func(tidv ...zodb.Tid) setTid {
+		s := setTid{}
+		for _, tid := range tidv {
+			s.Add(tid)
+		}
+		return s
+	}
+
+	δ1 := δ{1:{1,2}}
+	δ2 := δ{2:{2,3}};  δ22 := δ{22:{0,1}};  δ2_22 := δ{2:{2,3}, 22:{0,1}}
+	δ3 := δ{3:{3,4}}
+	δ4 := δ{4:{4,5}};  δ44 := δ{44:{0,1}};  δ4_44 := δ{4:{4,5}, 44:{0,1}}
+	δ5 := δ{5:{5,6}}
+	δ12 := δ{1:{1,2}, 2:{2,3}}
+	Δ101 := Δ{0x101, δ1}
+	Δ102 := Δ{0x102, δ2}
+	Δ103 := Δ{0x103, δ3}
+	Δ104 := Δ{0x104, δ4}
+	Δ105 := Δ{0x105, δ5}
+
+	// merge1
+	assertMerge1(nil,			Δ{0x100, nil}, false,
+		     nil)
+
+	assertMerge1(v(Δ{0x100, δ1}),		Δ{0x100, δ2}, false,
+		     v(Δ{0x100, δ12}))
+
+	assertMerge1(v(Δ101, Δ103),		Δ102, true,
+		     v(Δ101, Δ102, Δ103))
+
+	assertMerge1(v(Δ101, Δ102),		Δ103, true,
+		     v(Δ101, Δ102, Δ103))
+
+	assertMerge1(v(Δ102, Δ103),		Δ101, true,
+		     v(Δ101, Δ102, Δ103))
+
+	// merge
+	assertMerge(nil,			nil, r(),
+		    nil)
+
+	assertMerge(nil,			v(Δ101, Δ103),  r(0x101, 0x103),
+		    v(Δ101, Δ103))
+
+	assertMerge(v(Δ101, Δ103),		nil, r(),
+		    v(Δ101, Δ103))
+
+	assertMerge(v(Δ102, Δ104),		v(Δ101, Δ{0x102, δ22}, Δ103, Δ{0x104, δ44}, Δ105),
+						r(0x101, 0x103, 0x105),
+		    v(Δ101, Δ{0x102, δ2_22}, Δ103, Δ{0x104, δ4_44}, Δ105))
+}
 
 // -------- KAdj --------