promqltest: use AppenderV2 in load command (#18359)

* promqltest: use AppenderV2 in load command

Switch the PromQL test framework's load command from storage.Appender
to storage.AppenderV2 in appendSample, appendCustomHistogram and
appendTill. ST is set to 0 (unknown) for now; a follow-up will add
per-sample ST specification in load statements.

Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
Coded with Claude Sonnet 4.6.
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>

* promqltest: fix unchecked Rollback error

Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>
Coded with Claude Sonnet 4.6.
Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>

---------

Signed-off-by: György Krajcsovits <gyorgy.krajcsovits@grafana.com>

promql/promqltest/test.go

@@ -686,7 +686,7 @@ func (cmd *loadCmd) set(m labels.Labels, vals ...parser.SequenceValue) {
 }
 
 // append the defined time series to the storage.
-func (cmd *loadCmd) append(a storage.Appender) error {
+func (cmd *loadCmd) append(a storage.AppenderV2) error {
 	for h, smpls := range cmd.defs {
 		m := cmd.metrics[h]
 
@@ -737,7 +737,7 @@ func processClassicHistogramSeries(m labels.Labels, name string, histogramMap ma
 
 // If classic histograms are defined, convert them into native histograms with custom
 // bounds and append the defined time series to the storage.
-func (cmd *loadCmd) appendCustomHistogram(a storage.Appender) error {
+func (cmd *loadCmd) appendCustomHistogram(a storage.AppenderV2) error {
 	histogramMap := map[uint64]tempHistogramWrapper{}
 
 	// Go through all the time series to collate classic histogram data
@@ -800,17 +800,13 @@ func (cmd *loadCmd) appendCustomHistogram(a storage.Appender) error {
 	return nil
 }
 
-func appendSample(a storage.Appender, s promql.Sample, m labels.Labels) error {
+func appendSample(a storage.AppenderV2, s promql.Sample, m labels.Labels) error {
 	if s.H != nil {
-		if _, err := a.AppendHistogram(0, m, s.T, nil, s.H); err != nil {
-			return err
-		}
-	} else {
-		if _, err := a.Append(0, m, s.T, s.F); err != nil {
-			return err
-		}
+		_, err := a.Append(0, m, 0, s.T, 0, nil, s.H, storage.AppendV2Options{})
+		return err
 	}
-	return nil
+	_, err := a.Append(0, m, 0, s.T, s.F, nil, nil, storage.AppendV2Options{})
+	return err
 }
 
 // evalCmd is a command that evaluates an expression for the given time (range)
@@ -1448,9 +1444,9 @@ func (t *test) exec(tc testCommand, engine promql.QueryEngine) error {
 		t.clear()
 
 	case *loadCmd:
-		app := t.storage.Appender(t.context)
+		app := t.storage.AppenderV2(t.context)
 		if err := cmd.append(app); err != nil {
-			app.Rollback()
+			_ = app.Rollback()
 			return err
 		}
 
@@ -1772,7 +1768,7 @@ func (ll *LazyLoader) clear() error {
 
 // appendTill appends the defined time series to the storage till the given timestamp (in milliseconds).
 func (ll *LazyLoader) appendTill(ts int64) error {
-	app := ll.storage.Appender(ll.Context())
+	app := ll.storage.AppenderV2(ll.Context())
 	for h, smpls := range ll.loadCmd.defs {
 		m := ll.loadCmd.metrics[h]
 		for i, s := range smpls {