app/vmctl: fix match expression for vm-native protocol with --vm-native-disable-per-metric-migration flag enabled (#7310)

Fixes https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7309

### Describe Your Changes

Please provide a brief description of the changes you made. Be as
specific as possible to help others understand the purpose and impact of
your modifications.

### Checklist

The following checks are **mandatory**:

- [ ] My change adheres [VictoriaMetrics contributing
guidelines](https://docs.victoriametrics.com/contributing/).

---------

Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: hagen1778 <roman@victoriametrics.com>

app/vmctl/vm_native.go

@@ -120,7 +120,7 @@ func (p *vmNativeProcessor) runSingle(ctx context.Context, f native.Filter, srcU
 	if p.disablePerMetricRequests {
 		pr := bar.NewProxyReader(reader)
 		if pr != nil {
-			reader = bar.NewProxyReader(reader)
+			reader = pr
 			fmt.Printf("Continue import process with filter %s:\n", f.String())
 		}
 	}
@@ -193,7 +193,15 @@ func (p *vmNativeProcessor) runBackfilling(ctx context.Context, tenantID string,
 	var metrics = map[string][][]time.Time{
 		"": ranges,
 	}
+
+	format := nativeSingleProcessTpl
+	barPrefix := "Requests to make"
+	if p.interCluster {
+		barPrefix = fmt.Sprintf("Requests to make for tenant %s", tenantID)
+	}
+
 	if !p.disablePerMetricRequests {
+		format = fmt.Sprintf(nativeWithBackoffTpl, barPrefix)
 		metrics, err = p.explore(ctx, p.src, tenantID, ranges)
 		if err != nil {
 			return fmt.Errorf("failed to explore metric names: %s", err)
@@ -223,15 +231,7 @@ func (p *vmNativeProcessor) runBackfilling(ctx context.Context, tenantID string,
 		log.Print(foundSeriesMsg)
 	}
 
-	barPrefix := "Requests to make"
+	bar := barpool.NewSingleProgress(format, requestsToMake)
-	if p.interCluster {
-		barPrefix = fmt.Sprintf("Requests to make for tenant %s", tenantID)
-	}
-
-	bar := barpool.NewSingleProgress(fmt.Sprintf(nativeWithBackoffTpl, barPrefix), requestsToMake)
-	if p.disablePerMetricRequests {
-		bar = barpool.NewSingleProgress(nativeSingleProcessTpl, 0)
-	}
 	bar.Start()
 	defer bar.Finish()
 
@@ -362,16 +362,17 @@ func byteCountSI(b int64) string {
 }
 
 func buildMatchWithFilter(filter string, metricName string) (string, error) {
-	if filter == metricName {
-		return filter, nil
-	}
-	nameFilter := fmt.Sprintf("__name__=%q", metricName)
-
 	tfss, err := searchutils.ParseMetricSelector(filter)
 	if err != nil {
 		return "", err
 	}
 
+	if filter == metricName || metricName == "" {
+		return filter, nil
+	}
+
+	nameFilter := fmt.Sprintf("__name__=%q", metricName)
+
 	var filters []string
 	for _, tfs := range tfss {
 		var a []string

app/vmctl/vm_native_test.go

@@ -293,6 +293,9 @@ func TestBuildMatchWithFilter_Success(t *testing.T) {
 	// only label with regexp
 	f(`{cluster=~".*"}`, "http_request_count_total", `{cluster=~".*",__name__="http_request_count_total"}`)
 
+	// only label with regexp, empty metric name
+	f(`{cluster=~".*"}`, "", `{cluster=~".*"}`)
+
 	// many labels in filter with regexp
 	f(`{cluster=~".*",job!=""}`, "http_request_count_total", `{cluster=~".*",job!="",__name__="http_request_count_total"}`)
 
@@ -307,4 +310,7 @@ func TestBuildMatchWithFilter_Success(t *testing.T) {
 
 	// metric name has negative regexp
 	f(`{__name__!~".*"}`, "http_request_count_total", `{__name__="http_request_count_total"}`)
+
+	// metric name has negative regex and metric name is empty
+	f(`{__name__!~".*"}`, "", `{__name__!~".*"}`)
 }

docs/changelog/CHANGELOG.md

@@ -17,9 +17,11 @@ The sandbox cluster installation runs under the constant load generated by
 See also [LTS releases](https://docs.victoriametrics.com/lts-releases/).
 
 ## tip
+
 * FEATURE: [vmalert](https://docs.victoriametrics.com/vmalert/): `-rule` cmd-line flag now supports multi-document YAML files. This could be useful when rules are retrieved via HTTP URL where multiple rule files were merged together in one response. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/6753). Thanks to @Irene-123 for [the pull request](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/6995).
 
 * BUGFIX: [vmalert](https://docs.victoriametrics.com/vmalert): properly set `group_name` and `file` fields for recording rules in `/api/v1/rules`.
+* BUGFIX: [vmctl](https://docs.victoriametrics.com/vmctl/): fix issue with series matching for `vmctl vm-native` with `--vm-native-disable-per-metric-migration` flag enabled. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/7309).
 
 ## [v1.105.0](https://github.com/VictoriaMetrics/VictoriaMetrics/releases/tag/v1.105.0)