refactor! split SubplotError::IoError into more specific errors

Replace SubplotError::IoError with ::Spawn, ::WriteToChild,
::WaitForChild, ::ReadFile, ::CreateFile, ::Writefile.

IoError was a catchall error and as such, so generic that it didn't
help the user to figure out what actually is wrong. For example, there
was no indication what operation was attempted or on what file. The
new error variants are specific.

Sponsored-by: author

1 files changed, 23 insertions, 10 deletions

diff --git a/src/error.rs b/src/error.rs
index f9608a8..f0d76e3 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -259,16 +259,29 @@ pub enum SubplotError {
     #[error("no scenarios were found matching the `{0}` template")]
     NoScenariosMatched(String),
 
-    /// I/O error
-    ///
-    /// Subplot did some I/O, and it failed. This is a generic wrapper
-    /// for any kind of I/O error.
-    #[error(transparent)]
-    IoError {
-        /// The wrapped error.
-        #[from]
-        source: std::io::Error,
-    },
+    /// Failed to invoke a program.
+    #[error("Failed to invoke {0}")]
+    Spawn(PathBuf, #[source] std::io::Error),
+
+    /// Failed to write to stdin of child process.
+    #[error("Failed to write to stdin of child process")]
+    WriteToChild(#[source] std::io::Error),
+
+    /// Error when waiting for child process to finish.
+    #[error("Error when waiting for child process to finish")]
+    WaitForChild(#[source] std::io::Error),
+
+    /// Error when reading a file.
+    #[error("Error when reading {0}")]
+    ReadFile(PathBuf, #[source] std::io::Error),
+
+    /// Error when creating a file.
+    #[error("Error when creating {0}")]
+    CreateFile(PathBuf, #[source] std::io::Error),
+
+    /// Error when writing to a file.
+    #[error("Error when writing to {0}")]
+    WriteFile(PathBuf, #[source] std::io::Error),
 
     /// Pandoc error
     ///