fix: say for which file lookup of input file mtime fails

Sponsored-by: author

2 files changed, 12 insertions, 1 deletions

diff --git a/src/bin/subplot.rs b/src/bin/subplot.rs
index 907e616..a85ad62 100644
--- a/src/bin/subplot.rs
+++ b/src/bin/subplot.rs
@@ -308,7 +308,10 @@ impl Docgen {
     }
 
     fn mtime(filename: &Path) -> Result<(u64, u32)> {
-        let mtime = fs::metadata(filename)?.modified()?;
+        let mtime = fs::metadata(filename)
+            .map_err(|e| SubplotError::InputFileUnreadable(filename.into(), e))?
+            .modified()
+            .map_err(|e| SubplotError::InputFileMtime(filename.into(), e))?;
         let mtime = mtime.duration_since(UNIX_EPOCH)?;
         Ok((mtime.as_secs(), mtime.subsec_nanos()))
     }
diff --git a/src/error.rs b/src/error.rs
index 53eccad..a729bf0 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -321,6 +321,14 @@ pub enum SubplotError {
     /// String formatting failed.
     #[error("Failed in string formattiing: {0}")]
     StringFormat(std::fmt::Error),
+
+    /// Input file could not be read.
+    #[error("Failed to read input file {0}")]
+    InputFileUnreadable(PathBuf, #[source] std::io::Error),
+
+    /// Input file mtime lookup.
+    #[error("Failed to get modification time of {0}")]
+    InputFileMtime(PathBuf, #[source] std::io::Error),
 }
 
 impl SubplotError {