Improve OpenAPI parsing exception logging

src/Kiota.Builder/OpenApiDocumentDownloadService.cs

@@ -137,7 +137,17 @@ ex is SecurityException ||
         {
             // couldn't parse the URL, it's probably a local file
         }
-        var readResult = await OpenApiDocument.LoadAsync(input, settings: settings, cancellationToken: cancellationToken).ConfigureAwait(false);
+
+        ReadResult readResult;
+        try
+        {
+            readResult = await OpenApiDocument.LoadAsync(input, settings: settings, cancellationToken: cancellationToken).ConfigureAwait(false);
+        }
+        catch (Exception ex)
+        {
+            LogOpenApiParsingCriticalError(ex, config.OpenAPIFilePath);
+            throw;
+        }
         stopwatch.Stop();
         if (generatingMode && readResult.Diagnostic?.Warnings is { Count: > 0 })
             foreach (var warning in readResult.Diagnostic.Warnings)
@@ -188,6 +198,9 @@ ex is SecurityException ||
     [LoggerMessage(Level = LogLevel.Error, Message = "OpenAPI error: {Pointer} - {Message}")]
     private partial void LogOpenApiError(string? pointer, string message);
 
+    [LoggerMessage(Level = LogLevel.Critical, Message = "Error parsing specification {Path}")]
+    private partial void LogOpenApiParsingCriticalError(Exception exception, string path);
+
     [LoggerMessage(Level = LogLevel.Trace, Message = "{Timestamp}ms: Parsed OpenAPI successfully. {Count} paths found.")]
     private partial void LogParsedOpenApiSuccessfully(long timestamp, int count);
 }

tests/Kiota.Builder.Tests/OpenApiDocumentDownloadServiceTests.cs

@@ -30,7 +30,6 @@ public sealed class OpenApiDocumentDownloadServiceTests : IDisposable
               schema:
                 type: object";
 
-
     public void Dispose()
     {
         _httpClient.Dispose();
@@ -78,6 +77,51 @@ public async Task GetDocumentFromStreamAsyncTest_No_IncludeKiotaValidationRulesI
         Assert.Empty(logEntryForNoServerRule);
     }
 
+    [Fact]
+    public async Task GetDocumentFromStreamAsync_LogsSpecificationPathWhenParsingThrows()
+    {
+        const string brokenDocument = """
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "Repro API",
+    "version": "1.0.0"
+  },
+  "paths": {},
+  "components": {
+    "schemas": {
+      "ItemStatus": {
+        "type": "string",
+        "enum": [
+          "Active",
+          "Archived"
+        ],
+        "x-ms-enum-flags": []
+      }
+    }
+  }
+}
+""";
+
+        var generationConfig = new GenerationConfiguration
+        {
+            OpenAPIFilePath = "repro-broken.json"
+        };
+        var fakeLogger = new FakeLogger<OpenApiDocumentDownloadService>();
+
+        using var inputDocumentStream = CreateMemoryStreamFromString(brokenDocument);
+        var documentDownloadService = new OpenApiDocumentDownloadService(_httpClient, fakeLogger);
+
+        await Assert.ThrowsAsync<ArgumentOutOfRangeException>(() =>
+            documentDownloadService.GetDocumentFromStreamAsync(inputDocumentStream, generationConfig, cancellationToken: TestContext.Current.CancellationToken));
+
+        var parsingLogEntry = fakeLogger.LogEntries
+            .Where(l => l.message.Contains("Error parsing specification", StringComparison.OrdinalIgnoreCase));
+
+        var logEntry = Assert.Single(parsingLogEntry);
+        Assert.Contains("repro-broken.json", logEntry.message, StringComparison.OrdinalIgnoreCase);
+    }
+
     [Fact]
     public async Task GetDocumentFromStreamAsyncTest_Default_IncludeKiotaValidationRulesInConfig()
     {
@@ -107,4 +151,4 @@ private static Stream CreateMemoryStreamFromString(string s)
         stream.Position = 0;
         return stream;
     }
-}
+}