.

wcfs/internal/xbtree/δbtail.go

@@ -806,6 +806,7 @@ func (δBtail *ΔBtail) GetAt(ctx context.Context, root *Tree, key Key, at zodb.
 	// either use @tail[key], if it is present, or @head[key]
 	rev = δBtail.Tail()
 	revExact = false
+	// XXX kill KVAtTail completely
 	value, ok = δTtail.KVAtTail[key] // XXX kill - just use δvalue.Old from next-to-at entry
 	if ok {
 		return

wcfs/internal/zdata/δftail_test.go

@@ -205,6 +205,7 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 	blkTab   := map[int64]string{}                // #blk -> ZBlk<name>
 	dataTab  := map[string]string{}               // ZBlk<name> -> data
 	Zinblk   := map[string]setI64{}               // ZBlk<name> -> which #blk refer to it
+	blkRevAt := map[zodb.Tid]map[int64]zodb.Tid{} // {} at -> {} #blk -> rev
 
 	// initialize dataTab from root['treegen/values']
 	for /*oid*/_, zblki := range t.Head().ZBlkTab {
@@ -276,6 +277,19 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 		dTxt := "D" + dataTabTxt(dataTab)
 		commit := t.CommitTree(tTxt + " " + dTxt)
 
+		// update blkRevAt
+		var blkRevPrev map[int64]zodb.Tid
+		if i != 0 {
+			blkRevPrev = blkRevAt[δftail.Head()]
+		}
+		blkRev := map[int64]zodb.Tid{}
+		for blk, rev := range blkRevPrev {
+			blkRev[blk] = rev
+		}
+		for blk := range δblk {
+			blkRev[blk] = commit.At
+		}
+
 		var δfok *ΔFile
 		if len(δblk) != 0 {
 			δfok = &ΔFile{
@@ -375,7 +389,32 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 		}
 
 
-		// XXX LastBlkRev
+		// LastBlkRev
+
+		blkv := []int64{} // all blocks
+		for blk := range blkRevAt[vδf[len(vδf)-1].Rev] {
+			blkv = append(blkv, blk)
+		}
+		blkv = append(blkv, 1E4/*this block is hole*/)
+		sort.Slice(blkv, func(i, j int) bool {
+			return blkv[i] < blkv[j]
+		})
+
+		for j := 0; j < len(vδf); j++ {
+			at := vδf[j].Rev
+			blkRev := blkRevAt[at]
+			for _, blk := range blkv {
+				rev, exact := δftail.LastBlkRev(ctx, zfile, blk, at)
+				revOK, exactOK := blkRev[blk], true
+				if revOK <= δftail.Tail() {
+					revOK, exactOK = δftail.Tail(), false
+				}
+				if !(rev == revOK && exact == exactOK) {
+					t.Errorf("blkrev #%d @%s:\nhave: @%s, %v\nwant: @%s, %v", blk, at, rev, exact, revOK, exactOK)
+				}
+			}
+
+		}
 	}
 }