fix(parameters): return error on regex no-match for constrained template segments

Signed-off-by: Sai Asish Y <say.apm35@gmail.com>

Author: SAY-5

parameters/path_parameters.go

@@ -91,7 +91,9 @@ func (v *paramValidator) ValidatePathParamsWithPathItem(request *http.Request, p
 
 				matches := rgx.FindStringSubmatch(submittedSegments[x])
 				if matches == nil {
-					continue
+					validationErrors = append(validationErrors,
+						errors.PathParameterMissing(p, pathValue, request.URL.Path))
+					break
 				}
 				matches = matches[1:]
 

parameters/path_parameters_test.go

@@ -2395,7 +2395,7 @@ paths:
 func TestValidatePathParamsWithPathItem_RegexNoMatchContinues(t *testing.T) {
 	// When a submitted path segment does not match the regex for a
 	// constrained path template segment (e.g. {id:[0-9]+} vs "abc"), the
-	// nil-match guard must skip the segment without panicking.
+	// guard must not panic and must return a validation error.
 	spec := `openapi: 3.1.0
 paths:
   /items/{id:[0-9]+}:
@@ -2415,13 +2415,12 @@ paths:
 	m, _ := doc.BuildV3Model()
 	v := NewParameterValidator(&m.Model)
 
-	// "abc" does not match ^([0-9]+)$; the nil-match guard should skip the
-	// segment cleanly rather than panicking on a nil FindStringSubmatch result.
+	// "abc" does not match ^([0-9]+)$; expect invalid + at least one error.
 	req, _ := http.NewRequest(http.MethodGet, "https://example.com/items/abc", nil)
 	pathItem := m.Model.Paths.PathItems.GetOrZero("/items/{id:[0-9]+}")
 	require.NotNil(t, pathItem)
 
-	assert.NotPanics(t, func() {
-		v.ValidatePathParamsWithPathItem(req, pathItem, "/items/{id:[0-9]+}")
-	})
+	valid, errs := v.ValidatePathParamsWithPathItem(req, pathItem, "/items/{id:[0-9]+}")
+	assert.False(t, valid)
+	assert.NotEmpty(t, errs)
 }