story-kit: merge 225_story_surface_merge_conflicts_and_failures_in_the_web_ui

server/src/io/story_metadata.rs

@@ -6,6 +6,7 @@ use std::path::Path;
 pub struct StoryMetadata {
     pub name: Option<String>,
     pub coverage_baseline: Option<String>,
+    pub merge_failure: Option<String>,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -27,6 +28,7 @@ impl std::fmt::Display for StoryMetaError {
 struct FrontMatter {
     name: Option<String>,
     coverage_baseline: Option<String>,
+    merge_failure: Option<String>,
 }
 
 pub fn parse_front_matter(contents: &str) -> Result<StoryMetadata, StoryMetaError> {
@@ -58,6 +60,7 @@ fn build_metadata(front: FrontMatter) -> StoryMetadata {
     StoryMetadata {
         name: front.name,
         coverage_baseline: front.coverage_baseline,
+        merge_failure: front.merge_failure,
     }
 }
 
@@ -74,6 +77,24 @@ pub fn write_coverage_baseline(path: &Path, coverage_pct: f64) -> Result<(), Str
     Ok(())
 }
 
+/// Write or update a `merge_failure:` field in the YAML front matter of a story file.
+///
+/// The reason is stored as a quoted YAML string so that colons, hashes, and newlines
+/// in the failure message do not break front-matter parsing.
+/// If no front matter is present, this is a no-op (returns Ok).
+pub fn write_merge_failure(path: &Path, reason: &str) -> Result<(), String> {
+    let contents =
+        fs::read_to_string(path).map_err(|e| format!("Failed to read story file: {e}"))?;
+
+    // Produce a YAML-safe inline quoted string: collapse newlines, escape inner quotes.
+    let escaped = reason.replace('"', "\\\"").replace('\n', " ").replace('\r', "");
+    let yaml_value = format!("\"{escaped}\"");
+
+    let updated = set_front_matter_field(&contents, "merge_failure", &yaml_value);
+    fs::write(path, &updated).map_err(|e| format!("Failed to write story file: {e}"))?;
+    Ok(())
+}
+
 /// Insert or update a key: value pair in the YAML front matter of a markdown string.
 ///
 /// If no front matter (opening `---`) is found, returns the content unchanged.