feat(matrix): Fix matrix param type mismatch problem for ref array re…

…sult from customrun scenario

Adjust `resolveCustomResultRef` implementation in Tekton to handle array
results from CustomRun tasks correctly. This change resolves a type mismatch
issue when using array results as matrix parameters, ensuring compatibility
and proper functioning in scenarios where previous CustomRun emits array results.

pkg/reconciler/pipelinerun/resources/resultrefresolution.go

@@ -17,6 +17,7 @@ limitations under the License.
 package resources
 
 import (
+	"encoding/json"
 	"errors"
 	"fmt"
 	"sort"
@@ -164,13 +165,28 @@ func resolveCustomResultRef(customRuns []*v1beta1.CustomRun, resultRef *v1.Resul
 		return nil, err
 	}
 	return &ResolvedResultRef{
-		Value:           *v1.NewStructuredValues(runValue),
+		Value:           *paramValueFromCustomRunResult(runValue),
 		FromTaskRun:     "",
 		FromRun:         runName,
 		ResultReference: *resultRef,
 	}, nil
 }
 
+func paramValueFromCustomRunResult(result string) *v1.ParamValue {
+	var arrayResult []string
+	// for fan out array result, which is represented as string, we should make it to array type param value
+	if err := json.Unmarshal([]byte(result), &arrayResult); err == nil && len(arrayResult) > 0 {
+		if len(arrayResult) > 1 {
+			return v1.NewStructuredValues(arrayResult[0], arrayResult[1:]...)
+		}
+		return &v1.ParamValue{
+			Type:     v1.ParamTypeArray,
+			ArrayVal: []string{arrayResult[0]},
+		}
+	}
+	return v1.NewStructuredValues(result)
+}
+
 func resolveResultRef(taskRuns []*v1.TaskRun, resultRef *v1.ResultRef) (*ResolvedResultRef, error) {
 	taskRun := taskRuns[0]
 	taskRunName := taskRun.Name

pkg/reconciler/pipelinerun/resources/resultrefresolution_test.go

@@ -841,3 +841,53 @@ func TestValidateArrayResultsIndex(t *testing.T) {
 		})
 	}
 }
+
+func TestParamValueFromCustomRunResult(t *testing.T) {
+	type args struct {
+		result string
+	}
+	tests := []struct {
+		name string
+		args args
+		want *v1.ParamValue
+	}{
+		{
+			name: "multiple array elements result",
+			args: args{
+				result: `["amd64", "arm64"]`,
+			},
+			want: &v1.ParamValue{
+				Type:     "array",
+				ArrayVal: []string{"amd64", "arm64"},
+			},
+		},
+		{
+			name: "single array elements result",
+			args: args{
+				result: `[ "amd64" ]`,
+			},
+			want: &v1.ParamValue{
+				Type:     "array",
+				ArrayVal: []string{"amd64"},
+			},
+		},
+		{
+			name: "simple string result",
+			args: args{
+				result: "amd64",
+			},
+			want: &v1.ParamValue{
+				Type:      "string",
+				StringVal: "amd64",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := paramValueFromCustomRunResult(tt.args.result)
+			if d := cmp.Diff(tt.want, got); d != "" {
+				t.Fatalf("paramValueFromCustomRunResult %s", diff.PrintWantGot(d))
+			}
+		})
+	}
+}