What's wrong
In Frontmatter/YamlSerializer.cs (around lines 71–75), TryParseYamlObject calls Deserializer.Deserialize<Dictionary<object, object>>(input) and then runs foreach over the result. YamlDotNet returns null for a YAML document with no content: a comment only (# TODO), ~, or null. The foreach then throws NullReferenceException.
The method catches only YamlException, InvalidOperationException and ArgumentException, so the NRE escapes through ExtractFrontmatterObjects into every public entry point that parses the block.
Failure scenario (reproduced)
A draft file with a placeholder comment where the metadata will go:
Frontmatter.ExtractBody(input) throws instead of returning "Body text".Frontmatter.ExtractFrontmatter(input) throws instead of returning null (or an empty dictionary).RemoveFrontmatter and CombineFrontmatter throw as well.
Repro (MSTest, fails today):
[TestMethod]
public void CommentOnlyFrontmatter_DoesNotThrow()
{
string input = "---\n# nothing here yet\n---\nBody text\n";
Assert.AreEqual("Body text", Frontmatter.ExtractBody(input));
}
[TestMethod]
public void CommentOnlyFrontmatter_ExtractFrontmatter_DoesNotThrow()
{
Assert.IsNull(Frontmatter.ExtractFrontmatter("---\n# draft\n---\nBody\n"));
}Observed: System.NullReferenceException at ktsu.Frontmatter.YamlSerializer.TryParseYamlObject (YamlSerializer.cs:75).
A tool that walks a folder of Markdown files stops at the first file that has a commented-out or null frontmatter block.
Suggested fix
Straight after the Deserialize call, add if (rawData is null) { return false; }. If an empty block should count as "has frontmatter", return an empty dictionary instead.
Acceptance: tests covering comment-only, ~ and null frontmatter blocks. ExtractBody returns the body, and ExtractFrontmatter, RemoveFrontmatter and CombineFrontmatter don't throw.
What's wrong
In
Frontmatter/YamlSerializer.cs(around lines 71–75),TryParseYamlObjectcallsDeserializer.Deserialize<Dictionary<object, object>>(input)and then runsforeachover the result. YamlDotNet returnsnullfor a YAML document with no content: a comment only (# TODO),~, ornull. Theforeachthen throwsNullReferenceException.The method catches only
YamlException,InvalidOperationExceptionandArgumentException, so the NRE escapes throughExtractFrontmatterObjectsinto every public entry point that parses the block.Failure scenario (reproduced)
A draft file with a placeholder comment where the metadata will go:
Frontmatter.ExtractBody(input)throws instead of returning"Body text".Frontmatter.ExtractFrontmatter(input)throws instead of returningnull(or an empty dictionary).RemoveFrontmatterandCombineFrontmatterthrow as well.Repro (MSTest, fails today):
Observed:
System.NullReferenceException at ktsu.Frontmatter.YamlSerializer.TryParseYamlObject (YamlSerializer.cs:75).A tool that walks a folder of Markdown files stops at the first file that has a commented-out or
nullfrontmatter block.Suggested fix
Straight after the
Deserializecall, addif (rawData is null) { return false; }. If an empty block should count as "has frontmatter", return an empty dictionary instead.Acceptance: tests covering comment-only,
~andnullfrontmatter blocks.ExtractBodyreturns the body, andExtractFrontmatter,RemoveFrontmatterandCombineFrontmatterdon't throw.