fix: tolerate invalid markdown front matter

Arlodotexe · Arlodotexe · commit 208c91a508ea · 2026-05-16T17:15:07.000-05:00
diff --git a/src/Blog/Page/HtmlTemplatedMarkdownFile.cs b/src/Blog/Page/HtmlTemplatedMarkdownFile.cs
@@ -212,7 +212,10 @@ protected virtual Dictionary<string, object> ParseFrontmatter(string yaml)
             }
             catch (YamlDotNet.Core.YamlException ex)
             {
-                throw new InvalidOperationException($"Failed to parse YAML front-matter: {ex.Message}", ex);
+                return new Dictionary<string, object>
+                {
+                    ["frontmatter_parse_error"] = ex.Message,
+                };
             }
         }
 
diff --git a/tests/Blog/BlogCommandMaterializationTests.cs b/tests/Blog/BlogCommandMaterializationTests.cs
@@ -179,6 +179,40 @@ public async Task PagesCommand_IncludesLinkedMarkdownOutsideSourceRootRecursivel
         }
     }
 
+    [TestMethod]
+    public async Task PagesCommand_DoesNotAbortOnInvalidYamlFrontmatter()
+    {
+        var tempRoot = CreateTempRoot();
+
+        try
+        {
+            var sourceFolder = Path.Combine(tempRoot, "source");
+            var templateFolder = Path.Combine(tempRoot, "template");
+            var outputFolder = Path.Combine(tempRoot, "output");
+
+            Directory.CreateDirectory(sourceFolder);
+            Directory.CreateDirectory(templateFolder);
+            Directory.CreateDirectory(outputFolder);
+
+            await File.WriteAllTextAsync(Path.Combine(sourceFolder, "bad-yaml.md"), "---\ntitle: \"C:\\Projects\\Atlas\"\n---\n\n# Still renders");
+            await File.WriteAllTextAsync(Path.Combine(templateFolder, "template.html"), "<html><body>{{ body }}</body></html>");
+
+            var exitCode = await new PagesCommand().InvokeAsync([
+                "--markdown-folder", sourceFolder,
+                "--template", templateFolder,
+                "--output", outputFolder]);
+
+            var generatedHtml = await File.ReadAllTextAsync(Path.Combine(outputFolder, "bad-yaml", "index.html"));
+
+            Assert.AreEqual(0, exitCode);
+            StringAssert.Contains(generatedHtml, "Still renders");
+        }
+        finally
+        {
+            DeleteTempRoot(tempRoot);
+        }
+    }
+
     private static string CreateTempRoot()
     {
         var tempRoot = Path.Combine(Path.GetTempPath(), "wac-blog-tests", Guid.NewGuid().ToString("N"));

Original file line number	Diff line number	Diff line change
`@@ -212,7 +212,10 @@ protected virtual Dictionary<string, object> ParseFrontmatter(string yaml)`
`212`	`212`	`}`
`213`	`213`	`catch (YamlDotNet.Core.YamlException ex)`
`214`	`214`	`{`
`215`		`- throw new InvalidOperationException($"Failed to parse YAML front-matter: {ex.Message}", ex);`
	`215`	`+ return new Dictionary<string, object>`
	`216`	`+ {`
	`217`	`+ ["frontmatter_parse_error"] = ex.Message,`
	`218`	`+ };`
`216`	`219`	`}`
`217`	`220`	`}`
`218`	`221`