fix: Make parser handle meta lines in chunk

The previous parser for Git chunks would fail to properly break
up chunks with any "meta lines" (my term for them) starting with
a `\` instead of `+` or `-`. This update to the parser means the
parser will now correctly handle those lines, but won't include
them in the patch string it constructs, as they're meta-commentary
on the diff itself and not part of the edits.

Signed-off-by: Andrew Lilley Brinker <[email protected]>
Co-authored-by: Julian Lanson <[email protected]>

plugins/git/src/main.rs

@@ -153,6 +153,15 @@ async fn commit_diffs(engine: &mut PluginEngine, repo: LocalGitRepo) -> Result<V
 		Error::UnspecifiedQueryState
 	})?;
 
+	if commits.len() != diffs.len() {
+		log::error!(
+			"parsed {} diffs but there are {} commits",
+			diffs.len(),
+			commits.len()
+		);
+		return Err(Error::UnspecifiedQueryState);
+	}
+
 	let commit_diffs = Iterator::zip(commits.iter(), diffs.iter())
 		.map(|(commit, diff)| CommitDiff {
 			commit: commit.clone(),
@@ -436,3 +445,14 @@ async fn main() -> Result<()> {
 	let args = Args::try_parse().unwrap();
 	PluginServer::register(GitPlugin {}).listen(args.port).await
 }
+
+#[cfg(test)]
+mod test {
+	#[test]
+	fn test_no_newline_before_end_of_chunk() {
+		let input = "diff --git a/plugins/review/plugin.kdl b/plugins/review/plugin.kdl\nindex 83f0355..9fa8e47 100644\n--- a/plugins/review/plugin.kdl\n+++ b/plugins/review/plugin.kdl\n@@ -6,4 +6,4 @@ entrypoint {\n-  on arch=\"aarch64-apple-darwin\" \"./hc-mitre-review\"\n-  on arch=\"x86_64-apple-darwin\" \"./hc-mitre-review\"\n-  on arch=\"x86_64-unknown-linux-gnu\" \"./hc-mitre-review\"\n-  on arch=\"x86_64-pc-windows-msvc\" \"./hc-mitre-review\"\n+  on arch=\"aarch64-apple-darwin\" \"./target/debug/review_sdk\"\n+  on arch=\"x86_64-apple-darwin\" \"./target/debug/review_sdk\"\n+  on arch=\"x86_64-unknown-linux-gnu\" \"./target/debug/review_sdk\"\n+  on arch=\"x86_64-pc-windows-msvc\" \"./target/debug/review_sdk\"\n@@ -14 +14 @@ dependencies {\n-}\n\\ No newline at end of file\n+}\n";
+
+		let (leftover, _parsed) = crate::parse::patch(input).unwrap();
+		assert!(leftover.is_empty());
+	}
+}

plugins/git/src/parse.rs

@@ -265,20 +265,24 @@ fn patch_header(input: &str) -> IResult<&str, &str> {
 	recognize(tuple((metas, line, line)))(input)
 }
 
-fn plus_or_minus(input: &str) -> IResult<&str, &str> {
-	recognize(one_of("+-"))(input)
+fn chunk_prefix(input: &str) -> IResult<&str, &str> {
+	recognize(one_of("+-\\"))(input)
 }
 
 fn line_with_ending(input: &str) -> IResult<&str, &str> {
 	recognize(tuple((not_line_ending, line_ending)))(input)
 }
 
 fn chunk_line(input: &str) -> IResult<&str, &str> {
-	preceded(plus_or_minus, line_with_ending)(input)
+	preceded(chunk_prefix, line_with_ending)(input)
 }
 
 fn chunk_body(input: &str) -> IResult<&str, String> {
 	fold_many0(chunk_line, String::new, |mut patch, line| {
+		if line == " No newline at end of file\n" {
+			return patch;
+		}
+
 		patch.push_str(line);
 		patch
 	})(input)
@@ -307,7 +311,7 @@ fn patch_footer(input: &str) -> IResult<&str, Option<&str>> {
 	opt(no_newline)(input)
 }
 
-fn patch(input: &str) -> IResult<&str, String> {
+pub(crate) fn patch(input: &str) -> IResult<&str, String> {
 	tuple((patch_header, chunks, patch_footer))(input).map(|(i, (_, chunks, _))| (i, chunks))
 }
 
@@ -612,13 +616,13 @@ use serde::{Serialize, Deserialize};\n";
 		let input_plus = "+";
 		let expected_plus = "+";
 
-		let (remaining, c) = plus_or_minus(input_plus).unwrap();
+		let (remaining, c) = chunk_prefix(input_plus).unwrap();
 		assert_eq!("", remaining);
 		assert_eq!(expected_plus, c);
 
 		let input_minus = "-";
 		let expected_minus = "-";
-		let (remaining, c) = plus_or_minus(input_minus).unwrap();
+		let (remaining, c) = chunk_prefix(input_minus).unwrap();
 		assert_eq!("", remaining);
 		assert_eq!(expected_minus, c);
 	}