fix: wrap extension parser calls in try-catch to ensure correct error pointers

When extension parsers throw OpenApiException, the exceptions are now caught in LoadExtension methods across all OpenAPI versions (V2, V3, V3.1, V3.2). This ensures the error pointer correctly includes all path segments (e.g., #/definitions/demo/x-tag instead of #/definitions/x-tag).

Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

refactor: make V2 LoadExtension consistent with other versions

Moved the return statement for JsonNodeExtension outside the catch block to match the pattern used in V3, V31, and V32 deserializers.

Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

style: use raw string literals for JSON test data

Changed from verbatim string literals (@"...") to raw string literals ("""...""") for consistency with existing test code.

Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

chore: refactors test definition for better coverage

Signed-off-by: Vincent Biret <vibiret@microsoft.com>

chore: removes extraneous version

Author: Copilot

src/Microsoft.OpenApi/Reader/V2/OpenApiV2Deserializer.cs

@@ -79,12 +79,18 @@ private static IOpenApiExtension LoadExtension(string name, ParseNode node)
         {
             if (node.Context.ExtensionParsers is not null && node.Context.ExtensionParsers.TryGetValue(name, out var parser))
             {
-                return parser(node.CreateAny(), OpenApiSpecVersion.OpenApi2_0);
-            }
-            else
-            {
-                return new JsonNodeExtension(node.CreateAny());
+                try
+                {
+                    return parser(node.CreateAny(), OpenApiSpecVersion.OpenApi2_0);
+                }
+                catch (OpenApiException ex)
+                {
+                    ex.Pointer = node.Context.GetLocation();
+                    node.Context.Diagnostic.Errors.Add(new(ex));
+                }
             }
+
+            return new JsonNodeExtension(node.CreateAny());
         }
 
         private static string? LoadString(ParseNode node)

src/Microsoft.OpenApi/Reader/V3/OpenApiV3Deserializer.cs

@@ -130,15 +130,24 @@ public static JsonNodeExtension LoadAny(ParseNode node, OpenApiDocument hostDocu
 
         private static IOpenApiExtension LoadExtension(string name, ParseNode node)
         {
-            if (node.Context.ExtensionParsers is not null && node.Context.ExtensionParsers.TryGetValue(name, out var parser) && parser(
-                node.CreateAny(), OpenApiSpecVersion.OpenApi3_0) is { } result)
+            if (node.Context.ExtensionParsers is not null && node.Context.ExtensionParsers.TryGetValue(name, out var parser))
             {
-                return result;
-            }
-            else
-            {
-                return new JsonNodeExtension(node.CreateAny());
+                try
+                {
+                    var result = parser(node.CreateAny(), OpenApiSpecVersion.OpenApi3_0);
+                    if (result is { })
+                    {
+                        return result;
+                    }
+                }
+                catch (OpenApiException ex)
+                {
+                    ex.Pointer = node.Context.GetLocation();
+                    node.Context.Diagnostic.Errors.Add(new(ex));
+                }
             }
+
+            return new JsonNodeExtension(node.CreateAny());
         }
 
         private static string? LoadString(ParseNode node)

src/Microsoft.OpenApi/Reader/V31/OpenApiV31Deserializer.cs

@@ -131,9 +131,20 @@ public static JsonNode LoadAny(ParseNode node, OpenApiDocument hostDocument)
 
         private static IOpenApiExtension LoadExtension(string name, ParseNode node)
         {
-            return node.Context.ExtensionParsers is not null && node.Context.ExtensionParsers.TryGetValue(name, out var parser)
-                ? parser(node.CreateAny(), OpenApiSpecVersion.OpenApi3_1)
-                : new JsonNodeExtension(node.CreateAny());
+            if (node.Context.ExtensionParsers is not null && node.Context.ExtensionParsers.TryGetValue(name, out var parser))
+            {
+                try
+                {
+                    return parser(node.CreateAny(), OpenApiSpecVersion.OpenApi3_1);
+                }
+                catch (OpenApiException ex)
+                {
+                    ex.Pointer = node.Context.GetLocation();
+                    node.Context.Diagnostic.Errors.Add(new(ex));
+                }
+            }
+
+            return new JsonNodeExtension(node.CreateAny());
         }
 
         private static string? LoadString(ParseNode node)

test/Microsoft.OpenApi.Readers.Tests/TestCustomExtension.cs

@@ -44,6 +44,80 @@ public void ParseCustomExtension()
             Assert.Equal("hey", fooExtension.Bar);
             Assert.Equal("hi!", fooExtension.Baz);
         }
+
+        [Fact]
+        public void ExtensionParserThrowingOpenApiException_V2_ShouldHaveCorrectPointer()
+        {
+            var json = """
+{
+  "swagger": "2.0",
+  "info": {
+    "title": "Demo",
+    "version": "1"
+  },
+  "paths": {},
+  "definitions": {
+    "demo": {
+      "x-tag": null
+    }
+  }
+}
+""";
+            var settings = new OpenApiReaderSettings
+            {
+                ExtensionParsers =
+                {
+                    { "x-tag", (any, version) => throw new OpenApiException("Testing") }
+                }
+            };
+
+            var result = OpenApiDocument.Parse(json, "json", settings);
+
+            Assert.NotNull(result.Diagnostic);
+            Assert.NotEmpty(result.Diagnostic.Errors);
+            var error = result.Diagnostic.Errors[0];
+            Assert.Equal("Testing", error.Message);
+            Assert.Equal("#/definitions/demo/x-tag", error.Pointer);
+        }
+
+        [Theory]
+        [InlineData("3.0.4")]
+        [InlineData("3.1.1")]
+        public void ExtensionParserThrowingOpenApiException_V3_ShouldHaveCorrectPointer(string version)
+        {
+            var json = $$"""
+{
+  "openapi": "{{version}}",
+  "info": {
+    "title": "Demo",
+    "version": "1"
+  },
+  "paths": {},
+  "components": {
+    "schemas": {
+      "demo": {
+        "x-tag": null
+      }
+    }
+  }
+}
+""";
+            var settings = new OpenApiReaderSettings
+            {
+                ExtensionParsers =
+                {
+                    { "x-tag", (any, version) => throw new OpenApiException("Testing") }
+                }
+            };
+
+            var result = OpenApiDocument.Parse(json, "json", settings);
+
+            Assert.NotNull(result.Diagnostic);
+            Assert.NotEmpty(result.Diagnostic.Errors);
+            var error = result.Diagnostic.Errors[0];
+            Assert.Equal("Testing", error.Message);
+            Assert.Equal("#/components/schemas/demo/x-tag", error.Pointer);
+        }
     }
 
     internal class FooExtension : IOpenApiExtension, IOpenApiElement