X ΔFtail: `go test -failfast -short -v -run Random...

X ΔFtail: `go test -failfast -short -v -run Random -randseed=1626793016249041295` discovered problems

=== RUN   TestΔFtailRandom
    δftail_test.go:141: # n=10 seed=1626793016249041295
2021/07/23 12:26:01 zodb: FIXME: open /tmp/TestΔFtailRandom1363232041/001/1.fs: raw cache is not ready for invalidations -> NoCache forced
    δftail_test.go:191: #   @at0 (03e19cb6064c58dd)
    δftail_test.go:203: # → @at1 (03e19cb6064ddd99)  t0:a Da:a,b:b,c:c,d:d,e:e,f:f,g:g,h:h,i:i,j:j      ; not-yet-tracked
    δftail_test.go:375: # → @at2 (03e19cb6064fc922)  δT2:i,3:c,5:d,9:c  δD{a b c d e f g h i}   ; t0:a,2:i,3:c,5:d,9:c Da:a2,b:b2,c:c2,d:d2,e:e2,f:f2,g:g2,h:h2,i:i2,j:j        δ{0 2 3 5 9}
    δftail_test.go:472: δf:
        have: &{03e19cb6064fc922 false {2 3 5 9} true}
        want: &{03e19cb6064fc922 false {0 2 3 5 9} true}
    δftail_test.go:499: .trackSetZBlk:
        ~have: map[c:{3 9} d:{5} i:{2}]
         want: map[a:{0} c:{3 9} d:{5} i:{2}]

    ...

wcfs/internal/zdata/δftail.go

@@ -519,7 +519,7 @@ func (δftail *_ΔFileTail) forgetPast(revCut zodb.Tid) {
 //
 // Note: contrary to regular go slicing, low is exclusive while high is inclusive.
 func (δFtail *ΔFtail) SliceByFileRev(zfile *ZBigFile, lo, hi zodb.Tid) /*readonly*/[]*ΔFile {
-	//fmt.Printf("\n")
+	fmt.Printf("\nslice f<%s> (@%s,@%s]\n", zfile.POid(), lo, hi)
 	xtail.AssertSlice(δFtail, lo, hi)
 
 	// XXX locking
@@ -631,13 +631,13 @@ func (δFtail *ΔFtail) SliceByFileRev(zfile *ZBigFile, lo, hi zodb.Tid) /*reado
 		}
 
 		// merge vδZ and vδT of current epoch
-		for ((iz >= 0 && vδZ[iz].Rev >= epoch) || it >= 0) {
+		for ((iz >= 0 && vδZ[iz].Rev > epoch) || it >= 0) {	// XXX  ->  `δZ.Rev > epoch`
 			// δZ that is covered by current Zinblk
 			// -> update δf
-			if iz >= 0 {
+			if iz >= 0 && vδZ[iz].Rev > epoch {
 				δZ := vδZ[iz]
 				if ZinblkAt <= δZ.Rev {
-					//fmt.Printf("δZ @%s\n", δZ.Rev)
+					fmt.Printf("δZ @%s\n", δZ.Rev)
 					for _, oid := range δZ.Changev {
 						inblk, ok := Zinblk[oid]
 						if ok && len(inblk) != 0 {
@@ -653,7 +653,7 @@ func (δFtail *ΔFtail) SliceByFileRev(zfile *ZBigFile, lo, hi zodb.Tid) /*reado
 			// δT -> adjust Zinblk + update δf
 			if it >= 0 {
 				δT := vδT[it]
-				//fmt.Printf("δT @%s\n", δT.Rev)
+				fmt.Printf("δT @%s\n", δT.Rev)
 				for blk, δzblk := range δT.ΔKV {
 					// apply in reverse as we go ←
 					if δzblk.New != xbtree.VDEL {
@@ -727,7 +727,7 @@ func (δFtail *ΔFtail) BlkRevAt(ctx context.Context, zf *ZBigFile, blk int64, a
 func (δFtail *ΔFtail) _BlkRevAt(ctx context.Context, zf *ZBigFile, blk int64, at zodb.Tid) (_ zodb.Tid, exact bool, err error) {
 	defer xerr.Contextf(&err, "blkrev f<%s> #%d @%s", zf.POid(), blk, at)
 
-	//fmt.Printf("\nblkrev #%d @%s\n", blk, at)
+	fmt.Printf("\nblkrev #%d @%s\n", blk, at)
 
 	// assert at ∈ (tail, head]
 	tail := δFtail.Tail()
@@ -752,7 +752,7 @@ func (δFtail *ΔFtail) _BlkRevAt(ctx context.Context, zf *ZBigFile, blk int64,
 
 	// find epoch that covers at and associated blktab root/object
 	vδE := δftail.vδE
-	//fmt.Printf("  vδE: %v\n", vδE)
+	fmt.Printf("  vδE: %v\n", vδE)
 	l := len(vδE)
 	i := sort.Search(l, func(i int) bool {
 		return at < vδE[i].Rev
@@ -778,7 +778,7 @@ func (δFtail *ΔFtail) _BlkRevAt(ctx context.Context, zf *ZBigFile, blk int64,
 		epoch = vδE[i].Rev
 	}
 
-	//fmt.Printf("  epoch: @%s  root: %s\n", epoch, root)
+	fmt.Printf("  epoch: @%s  root: %s\n", epoch, root)
 
 	if root == xbtree.VDEL {
 		return epoch, true, nil
@@ -786,7 +786,7 @@ func (δFtail *ΔFtail) _BlkRevAt(ctx context.Context, zf *ZBigFile, blk int64,
 
 	zblk, tabRev, zblkExact, tabRevExact, err := δFtail.δBtail.GetAt(root, blk, at)
 
-	//fmt.Printf("  GetAt  #%d @%s  ->  %s(%v), @%s(%v)\n", blk, at, zblk, zblkExact, tabRev, tabRevExact)
+	fmt.Printf("  GetAt  #%d @%s  ->  %s(%v), @%s(%v)\n", blk, at, zblk, zblkExact, tabRev, tabRevExact)
 	if err != nil {
 		return zodb.InvalidTid, false, err
 	}
@@ -831,7 +831,7 @@ func (δFtail *ΔFtail) _BlkRevAt(ctx context.Context, zf *ZBigFile, blk int64,
 	// blktab[blk] was changed to point to a zblk @tabRev.
 	// blk revision is max rev and when zblk changed last in (rev, at] range.
 	zblkRev, zblkRevExact := δFtail.δBtail.ΔZtail().LastRevOf(zblk, at)
-	//fmt.Printf("  ZRevOf %s @%s -> @%s, %v\n", zblk, at, zblkRev, zblkRevExact)
+	fmt.Printf("  ZRevOf %s @%s -> @%s, %v\n", zblk, at, zblkRev, zblkRevExact)
 	if zblkRev > tabRev {
 		return zblkRev, zblkRevExact, nil
 	} else {

wcfs/internal/zdata/δftail_test.go

@@ -112,6 +112,12 @@ func TestΔFtail(t *testing.T) {
 		{δT{1:a,3:d,6:j},			δD(b,c,d,f,g,h,i,j)},
 		{δT{0:i,1:f,4:e,5:e,7:d,8:h},		δD(d,j)},
 		{δT{},					δD(a,b,c,e,f,g,h,i,j)},
+
+		// XXX
+		{nil, nil},
+		{δT{0:a},				δD()},
+		{δT{2:i,3:c,5:d,9:c},			δD(a,b,c,d,e,f,g,h,i)},
+		{δT{0:j,1:d,2:h,5:g,6:h,7:c,9:h},	δD(d,e,f,h,j)},
 	}
 
 	testq := make(chan ΔFTestEntry)
@@ -126,7 +132,8 @@ func TestΔFtail(t *testing.T) {
 
 // TestΔFtailRandom runs ΔFtail tests on randomly-generated file changes.
 func TestΔFtailRandom(t *testing.T) {
-	n    := xbtreetest.N(1E3, 1E4, 1E5)
+	//n    := xbtreetest.N(1E3, 1E4, 1E5)
+	n    := xbtreetest.N(1E1, 1E4, 1E5)	// XXX temp
 	nblk := xbtreetest.N(1E1, 2E1, 1E2) // keeps failures detail small on -short
 
 	// random-number generator
@@ -237,7 +244,7 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 				oldTrackSetZBlk: nil,
 			},
 		    }
-	blkTab   := map[int64]string{0:"a"}           // #blk -> ZBlk<name>
+	blkTab   := map[int64]string{}                // #blk -> ZBlk<name>
 	Zinblk   := map[string]setI64{}               // ZBlk<name> -> which #blk refer to it
 	blkRevAt := map[zodb.Tid]map[int64]zodb.Tid{} // {} at -> {} #blk -> rev
 
@@ -251,6 +258,9 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 
 
 	epochv := []zodb.Tid{t0.At, t1.At}
+	blkTab[0] = "a"         // matches t1
+	Zinblk["a"] = setI64{}  // matches t1
+	Zinblk["a"].Add(0)
 
 	// δfstr/vδfstr converts δf/vδf to string taking xat into account
 	δfstr := func(δf *ΔFile) string {
@@ -523,6 +533,7 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 		}
 
 
+		/*
 		// SliceByFileRev
 		for j := 0; j < len(vδf); j++ {
 			for k := j; k < len(vδf); k++ {
@@ -541,6 +552,8 @@ func testΔFtail(t_ *testing.T, testq chan ΔFTestEntry) {
 				}
 			}
 		}
+		*/
+		_ = vδfstr
 
 
 		// BlkRevAt