refactor: replace SubplotError::JsonError with a more specific one

SubplotError::JsonError is a generic error, but we actually only parse
JSON when parsing the AST from Pandoc. Replace it with a ::AstJson
error to be more specific, and hopefully more helpful to the user.

Sponsored-by: author

2 files changed, 5 insertions, 12 deletions

diff --git a/src/doc.rs b/src/doc.rs
index 71910f1..490a613 100644
--- a/src/doc.rs
+++ b/src/doc.rs
@@ -146,7 +146,7 @@ impl<'a> Document {
         P: AsRef<Path> + Debug,
     {
         trace!("Parsing document...");
-        let ast: Pandoc = serde_json::from_str(json)?;
+        let ast: Pandoc = serde_json::from_str(json).map_err(SubplotError::AstJson)?;
         Self::from_ast(basedir, markdowns, ast, style, template)
     }
 
@@ -217,7 +217,7 @@ impl<'a> Document {
     /// This is useful in a Pandoc filter, so that the filter can give
     /// it back to Pandoc for typesetting.
     pub fn ast(&self) -> Result<String, SubplotError> {
-        let json = serde_json::to_string(&self.ast)?;
+        let json = serde_json::to_string(&self.ast).map_err(SubplotError::AstJson)?;
         Ok(json)
     }
 
diff --git a/src/error.rs b/src/error.rs
index 8fdaeee..a42298d 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -294,16 +294,9 @@ pub enum SubplotError {
     #[error("Failed to compile regular expression: {0:?}")]
     Regex(String, #[source] regex::Error),
 
-    /// JSON error
-    ///
-    /// Subplot parses and generates JSON. This is a generic wrapper
-    /// for any kinds of errors related to that.
-    #[error(transparent)]
-    JsonError {
-        /// The wrapped error.
-        #[from]
-        source: serde_json::Error,
-    },
+    /// Error parsing the Pandoc abstract syntax tree as JSON.
+    #[error("Failed to parse document AST as JSON")]
+    AstJson(#[source] serde_json::Error),
 
     /// Error parsing YAML metadata for document.
     #[error("Failed to parse YAML metadata")]