throw missing field in std err

staging/src/k8s.io/kubectl/pkg/explain/v2/explain.go

@@ -18,6 +18,7 @@ package v2
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 
@@ -85,5 +86,12 @@ func printModelDescriptionWithGenerator(
 		return fmt.Errorf("failed to parse openapi schema for %s: %w", resourcePath, err)
 	}
 
-	return generator.Render(outputFormat, parsedV3Schema, gvr, fieldsPath, recursive, w)
+	err = generator.Render(outputFormat, parsedV3Schema, gvr, fieldsPath, recursive, w)
+
+	explainErr := explainError("")
+	if errors.As(err, &explainErr) {
+		return explainErr
+	}
+
+	return err
 }

staging/src/k8s.io/kubectl/pkg/explain/v2/funcs.go

@@ -29,8 +29,18 @@ import (
 	"k8s.io/kubectl/pkg/util/term"
 )
 
+type explainError string
+
+func (e explainError) Error() string {
+	return string(e)
+}
+
 func WithBuiltinTemplateFuncs(tmpl *template.Template) *template.Template {
 	return tmpl.Funcs(map[string]interface{}{
+		"throw": func(e string, args ...any) (string, error) {
+			errString := fmt.Sprintf(e, args...)
+			return "", explainError(errString)
+		},
 		"toJson": func(obj any) (string, error) {
 			res, err := json.Marshal(obj)
 			return string(res), err

staging/src/k8s.io/kubectl/pkg/explain/v2/templates/plaintext.tmpl

@@ -19,10 +19,10 @@
     {{- with include "schema" (dict "gvk" $gvk "Document" $.Document "FieldPath" $.FieldPath "Recursive" $.Recursive) -}}
         {{- . -}}
     {{- else -}}
-        error: GVK {{$gvk}} not found in OpenAPI schema
+        {{- throw "error: GVK %v not found in OpenAPI schema" $gvk -}}
     {{- end -}}
 {{- else -}}
-    error: GVR ({{$.GVR.String}}) not found in OpenAPI schema
+    {{- throw "error: GVR (%v) not found in OpenAPI schema" $.GVR.String -}}
 {{- end -}}
 {{- "\n" -}}
 
@@ -43,7 +43,8 @@ Takes dictionary as argument with keys:
             {{- with include "output" (set $ "schema" .) -}}
                 {{- . -}}
             {{- else -}}
-                error: field "{{index $.FieldPath (sub (len $.FieldPath) 1)}}" does not exist
+                {{- $fieldName := (index $.FieldPath (sub (len $.FieldPath) 1)) -}}
+                {{- throw "error: field \"%v\" does not exist" $fieldName}}
             {{- end -}}
             {{- break -}}
         {{- end -}}

staging/src/k8s.io/kubectl/pkg/explain/v2/templates/plaintext_test.go

@@ -66,21 +66,21 @@ type testCase struct {
 }
 
 type check interface {
-	doCheck(output string) error
+	doCheck(output string, err error) error
 }
 
 type checkError string
 
-func (c checkError) doCheck(output string) error {
+func (c checkError) doCheck(output string, err error) error {
-	if !strings.Contains(output, "error: "+string(c)) {
+	if !strings.Contains(err.Error(), "error: "+string(c)) {
-		return fmt.Errorf("expected error: '%v' in string:\n%v", string(c), output)
+		return fmt.Errorf("expected error: '%v' in string:\n%v", string(c), err)
 	}
 	return nil
 }
 
 type checkContains string
 
-func (c checkContains) doCheck(output string) error {
+func (c checkContains) doCheck(output string, err error) error {
 	if !strings.Contains(output, string(c)) {
 		return fmt.Errorf("expected substring: '%v' in string:\n%v", string(c), output)
 	}
@@ -89,7 +89,7 @@ func (c checkContains) doCheck(output string) error {
 
 type checkEquals string
 
-func (c checkEquals) doCheck(output string) error {
+func (c checkEquals) doCheck(output string, err error) error {
 	if output != string(c) {
 		return fmt.Errorf("output is not equal to expectation:\n%v", cmp.Diff(string(c), output))
 	}
@@ -123,7 +123,7 @@ func TestPlaintext(t *testing.T) {
 				Recursive: false,
 			},
 			Checks: []check{
-				checkError("GVR (/, Resource=) not found in OpenAPI schema\n"),
+				checkError("GVR (/, Resource=) not found in OpenAPI schema"),
 			},
 		},
 		{
@@ -158,7 +158,7 @@ func TestPlaintext(t *testing.T) {
 				Recursive: false,
 			},
 			Checks: []check{
-				checkError(`field "[does not exist]" does not exist`),
+				checkError(`field "exist" does not exist`),
 			},
 		},
 		{
@@ -564,16 +564,17 @@ func TestPlaintext(t *testing.T) {
 
 		t.Run(testName, func(t *testing.T) {
 			buf := bytes.NewBuffer(nil)
+
+			var outputErr error
 			if len(tcase.Subtemplate) == 0 {
-				tmpl.Execute(buf, tcase.Context)
+				outputErr = tmpl.Execute(buf, tcase.Context)
 			} else {
-				tmpl.ExecuteTemplate(buf, tcase.Subtemplate, tcase.Context)
+				outputErr = tmpl.ExecuteTemplate(buf, tcase.Subtemplate, tcase.Context)
 			}
-			require.NoError(t, err)
 
 			output := buf.String()
 			for _, check := range tcase.Checks {
-				err = check.doCheck(output)
+				err = check.doCheck(output, outputErr)
 
 				if err != nil {
 					t.Log("test failed on output:\n" + output)