make linter happy

In https://github.com/VictoriaMetrics/VictoriaMetrics/pull/10607 vmagent
metrics relabling debug UI has been refined. There are a few changes
that make sence in VMUI too:
- Rename "Labels" to "A time series" to highlight that a single
Prometheus time series can be provided in text format.
- Rename "Relabel Configs" to "Config". It should be clear from the page
contex what config is meant. Also there are links to documention.
- Add placeholder. It hints what could be placed into "A time series"
textarea.

app/vmselect/promql/binary_op.go

@@ -164,11 +164,11 @@ func newBinaryOpFunc(bf func(left, right float64, isBool bool) float64) binaryOp
 		left := bfa.left
 		right := bfa.right
 		op := bfa.be.Op
-		switch true {
-		case metricsql.IsBinaryOpCmp(op):
-			// Do not remove empty series for comparison operations,
-			// since this may lead to missing result.
-		default:
+		isCmpOp := metricsql.IsBinaryOpCmp(op)
+		if !isCmpOp {
+			// Do not remove empty series for comparison operations, since NaN can be an
+			// explicitly present sample value. In particular, `value != NaN` is true.
+			// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/150.
 			left = removeEmptySeries(left)
 			right = removeEmptySeries(right)
 		}
@@ -191,6 +191,14 @@ func newBinaryOpFunc(bf func(left, right float64, isBool bool) float64) binaryOp
 		isBool := bfa.be.Bool
 		fillLeft := bfa.be.FillLeft
 		fillRight := bfa.be.FillRight
+		// A NaN produced by a vector comparison denotes a filtered-out sample rather
+		// than an explicitly present NaN value. Drop it when this result is used as
+		// the right-hand side of another comparison.
+		// Note that filtered-out samples surviving as NaN inside other wrappers such as
+		// transform functions or arithmetic operations aren't detected, since such NaN
+		// is indistinguishable from an explicitly present NaN value there.
+		// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/10018.
+		dropNaNRight := isCmpOp && isVectorComparisonExpr(bfa.be.Right)
 		for i, tsLeft := range left {
 			leftValues := tsLeft.Values
 			rightValues := right[i].Values
@@ -203,11 +211,16 @@ func newBinaryOpFunc(bf func(left, right float64, isBool bool) float64) binaryOp
 				b := rightValues[j]
 				leftIsNaN := math.IsNaN(a)
 				rightIsNaN := math.IsNaN(b)
-				// apply the fill value when either the left or right side is NaN, but not both.
+				// Both sides are NaN.
 				if leftIsNaN && rightIsNaN {
 					dstValues[j] = bf(a, b, isBool)
 					continue
 				}
+				if dropNaNRight && rightIsNaN && fillRight == nil {
+					dstValues[j] = nan
+					continue
+				}
+				// Apply the fill value when either the left or right side is NaN, but not both.
 				if leftIsNaN && fillLeft != nil {
 					a = fillLeft.N
 				}
@@ -223,6 +236,38 @@ func newBinaryOpFunc(bf func(left, right float64, isBool bool) float64) binaryOp
 	}
 }
 
+// isVectorComparisonExpr returns whether e is a comparison operation
+// with at least one non-scalar operand.
+func isVectorComparisonExpr(e metricsql.Expr) bool {
+	if re, ok := e.(*metricsql.RollupExpr); ok && re.Window == nil {
+		// Unwrap `(...) offset <d>` and `(...) @ <t>`, which do not change
+		// the shape of the result. Subqueries are left as is, since rollup
+		// functions skip NaN values on their own.
+		e = re.Expr
+	}
+	be, ok := e.(*metricsql.BinaryOpExpr)
+	if !ok || !metricsql.IsBinaryOpCmp(be.Op) {
+		return false
+	}
+	return !isScalarLikeExpr(be.Left) || !isScalarLikeExpr(be.Right)
+}
+
+// isScalarLikeExpr returns whether e always evaluates to a scalar value.
+func isScalarLikeExpr(e metricsql.Expr) bool {
+	switch e := e.(type) {
+	case *metricsql.NumberExpr, *metricsql.DurationExpr:
+		return true
+	case *metricsql.BinaryOpExpr:
+		return isScalarLikeExpr(e.Left) && isScalarLikeExpr(e.Right)
+	case *metricsql.FuncExpr:
+		switch strings.ToLower(e.Name) {
+		case "now", "pi", "scalar", "start", "end", "step", "time", "timezone_offset":
+			return true
+		}
+	}
+	return false
+}
+
 func adjustBinaryOpTags(be *metricsql.BinaryOpExpr, left, right []*timeseries) ([]*timeseries, []*timeseries, []*timeseries, error) {
 	if len(be.GroupModifier.Op) == 0 && len(be.JoinModifier.Op) == 0 {
 		if isScalar(left) {

app/vmselect/promql/exec_test.go

@@ -2994,6 +2994,136 @@ func TestExecSuccess(t *testing.T) {
 		resultExpected := []netstorage.Result{}
 		f(q, resultExpected)
 	})
+	t.Run(`compare_to_nan_left_vector_right_scalar`, func(t *testing.T) {
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") != NaN`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{1000, 1200, 1400, 1600, 1800, 2000},
+			Timestamps: timestampsExpected,
+		}
+		r.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("foo"),
+			Value: []byte("bar"),
+		}}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_non_nan_scalar_right`, func(t *testing.T) {
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") != 1200`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{1000, nan, 1400, 1600, 1800, 2000},
+			Timestamps: timestampsExpected,
+		}
+		r.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("foo"),
+			Value: []byte("bar"),
+		}}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_nan_vector_right`, func(t *testing.T) {
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") != label_set(NaN, "foo", "bar")`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{1000, 1200, 1400, 1600, 1800, 2000},
+			Timestamps: timestampsExpected,
+		}
+		r.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("foo"),
+			Value: []byte("bar"),
+		}}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_nan_scalar_comparison_right`, func(t *testing.T) {
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") != (1 > 2)`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{1000, 1200, 1400, 1600, 1800, 2000},
+			Timestamps: timestampsExpected,
+		}
+		r.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("foo"),
+			Value: []byte("bar"),
+		}}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_empty_vector_right`, func(t *testing.T) {
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") != (label_set(time(), "foo", "bar") > 100000)`
+		resultExpected := []netstorage.Result{}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_empty_vector_right_offset`, func(t *testing.T) {
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") != ((label_set(time(), "foo", "bar") > 100000) offset 0s)`
+		resultExpected := []netstorage.Result{}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_empty_vector_left`, func(t *testing.T) {
+		// A missing sample on the left side results in NaN for every comparison
+		// operation, so no special handling is needed there.
+		t.Parallel()
+		q := `(label_set(time(), "foo", "bar") > 100000) != label_set(time(), "foo", "bar")`
+		resultExpected := []netstorage.Result{}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_empty_series_right_bool`, func(t *testing.T) {
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") == bool (label_set(time(), "foo", "bar") > 100000)`
+		resultExpected := []netstorage.Result{}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_partially_empty_series_right`, func(t *testing.T) {
+		// Prometheus drops the timestamps filtered out by the comparison on the right.
+		// See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/11100#issuecomment-4933952390.
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") != (label_set(time(), "foo", "bar") * 2 > 2800)`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{nan, nan, nan, 1600, 1800, 2000},
+			Timestamps: timestampsExpected,
+		}
+		r.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("foo"),
+			Value: []byte("bar"),
+		}}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_empty_unlabeled_vector_right`, func(t *testing.T) {
+		t.Parallel()
+		q := `sum(label_set(time(), "foo", "bar")) != (sum(label_set(time(), "foo", "bar")) > 100000)`
+		resultExpected := []netstorage.Result{}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_empty_series_right_with_fill_left`, func(t *testing.T) {
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") != fill_left(0) (label_set(time(), "foo", "bar") > 100000)`
+		resultExpected := []netstorage.Result{}
+		f(q, resultExpected)
+	})
+	t.Run(`compare_to_empty_series_right_with_fill_right`, func(t *testing.T) {
+		t.Parallel()
+		q := `label_set(time(), "foo", "bar") != fill_right(0) (label_set(time(), "foo", "bar") > 100000)`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{1000, 1200, 1400, 1600, 1800, 2000},
+			Timestamps: timestampsExpected,
+		}
+		r.MetricName.Tags = []storage.Tag{{
+			Key:   []byte("foo"),
+			Value: []byte("bar"),
+		}}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
 	t.Run(`-1 < 2`, func(t *testing.T) {
 		t.Parallel()
 		q := `-1 < 2`

app/vmui/packages/vmui/src/pages/Relabel/index.tsx

@@ -72,7 +72,7 @@ const Relabel: FC = () => {
         <div className="vm-relabeling-header-configs">
           <TextField
             type="textarea"
-            label="Relabel configs"
+            label="Config"
             value={config}
             autofocus
             onChange={handleChangeConfig}
@@ -82,8 +82,9 @@ const Relabel: FC = () => {
         <div className="vm-relabeling-header__labels">
           <TextField
             type="textarea"
-            label="Labels"
+            label="A time series"
             value={labels}
+            placeholder="up{job=&quot;job_name&quot;,instance=&quot;host:port&quot;}"
             onChange={handleChangeLabels}
             onEnter={handleRunQuery}
           />
@@ -97,22 +98,22 @@ const Relabel: FC = () => {
             <Button
               variant="text"
               color="gray"
-              startIcon={<InfoIcon/>}
+              startIcon={<WikiIcon/>}
             >
               Relabeling cookbook
             </Button>
           </a>
           <a
             target="_blank"
-            href="https://docs.victoriametrics.com/victoriametrics/relabeling/"
+            href="https://docs.victoriametrics.com/victoriametrics/relabeling/#relabeling-stages"
             rel="help noreferrer"
           >
             <Button
               variant="text"
               color="gray"
-              startIcon={<WikiIcon/>}
+              startIcon={<InfoIcon/>}
             >
-              Documentation
+              Relabeling Stages
             </Button>
           </a>
           <Button

docs/victoriametrics/changelog/CHANGELOG.md

@@ -34,6 +34,7 @@ See also [LTS releases](https://docs.victoriametrics.com/victoriametrics/lts-rel
 * FEATURE: [dashboards](https://github.com/VictoriaMetrics/VictoriaMetrics/tree/master/dashboards): add `Fsync avg duration` panel to the Troubleshooting section of the single-node, cluster, and vmagent dashboards. This panel surfaces degradation of IO operation for faster incident triage. See [#10432](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/10432).
 * FEATURE: [vmbackupmanager](https://docs.victoriametrics.com/victoriametrics/vmbackupmanager/) and [alerts](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/deployment/docker/rules): introduce `vm_backup_last_success_at` metric to track the last successful backup by type. Add [alerting rules](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/deployment/docker/rules/alerts-vmbackupmanager.yml) `NoLatestBackupWithinLastDay`, `NoHourlyBackupWithinLastDay`, `NoDailyBackupWithinLast3Days`, `NoWeeklyBackupWithinLast14Days` and `NoMonthlyBackupWithinLast62Days` to remind users about the missing backups. See [#11217](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/11217).
 
+* BUGFIX: [MetricsQL](https://docs.victoriametrics.com/victoriametrics/metricsql/): properly drop data points filtered out by an inner [comparison operation](https://prometheus.io/docs/prometheus/latest/querying/operators/#comparison-binary-operators) when its result is used on the right side of another comparison. Previously, queries like `foo != (bar > 100)` could return unexpected results because filtered-out data points are represented internally as `NaN`, and `value != NaN` evaluates to `true`. Comparisons against explicitly present `NaN` values keep the previous behavior. See [#10018](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/10018). Thanks to @zasdaym for contribution.
 * BUGFIX: [vmalert](https://docs.victoriametrics.com/victoriametrics/vmalert/): fixed the display of rule state badges on the `Groups` page in the web UI. See [#11160](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/11160).
 * BUGFIX: [vmbackupmanager](https://docs.victoriametrics.com/victoriametrics/vmbackupmanager/): previously, `vmbackupmanager` was crashing on startup when it failed to restore backup state from remote storage, causing a crash loop. Now it logs the error and continues running, retrying the state restore before each scheduled backup. Added `vm_backup_errors_total{type="restoreState"}` metric to track backup state restore failures. See [#11217](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/11217).
 
@@ -122,6 +123,7 @@ Released at 2026-06-22
 * BUGFIX: [vmsingle](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/) and `vmselect` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/): properly escape `metricFamilyName` at metrics metadata response. See [#11129](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/11129). Thanks for @fxrlv for the contribution.
 * BUGFIX: [vmsingle](https://docs.victoriametrics.com/victoriametrics/single-server-victoriametrics/) and `vmstorage` in [VictoriaMetrics cluster](https://docs.victoriametrics.com/victoriametrics/cluster-victoriametrics/): prevent more cases of panic during directory deletion on `NFS`-based mounts. See [#11060](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/11060).
 
+
 ## [v1.145.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.145.0)
 
 Released at 2026-06-08