Error handling

crates/cornucopia/src/codegen/vfs.rs

@@ -3,6 +3,8 @@ use std::{
     path::{Path, PathBuf},
 };
 
+use crate::error::PersistError;
+
 /// In memory storage of file
 /// Can only fail while persisting
 pub struct Vfs {
@@ -22,23 +24,23 @@ impl Vfs {
     }
 
     /// Materialize on real file system, overwrite existing directory if any
-    pub fn persist(self, destination: impl AsRef<Path>) -> std::io::Result<()> {
+    pub fn persist(self, destination: impl AsRef<Path>) -> Result<(), PersistError> {
         let destination = destination.as_ref();
         // First write in a temporary directory to prevent leaving the destination in a bad state
-        let tmp = tempfile::tempdir()?;
+        let tmp = tempfile::tempdir().map_err(PersistError::wrap("tempfile"))?;
         for (path, content) in self.fs {
             let path = tmp.path().join(path);
             let parent = path
                 .parent()
                 .expect("Must at least has 'destination' as parent");
             std::fs::create_dir_all(parent).ok(); // Might already exist
-            std::fs::write(path, content)?;
+            std::fs::write(&path, content).map_err(PersistError::wrap(path))?;
         }
         // Swap destination and tmp as atomically as possible
         // TODO is it possible to do this atomically for some platform ?
         std::fs::remove_dir_all(destination).ok(); // Might not exist
-        std::fs::create_dir_all(destination)?;
-        std::fs::rename(tmp.into_path(), destination)?;
+        std::fs::create_dir_all(destination).map_err(PersistError::wrap(destination))?;
+        std::fs::rename(tmp.into_path(), destination).map_err(PersistError::wrap(destination))?;
         Ok(())
     }
 }

crates/cornucopia/src/error.rs

@@ -22,8 +22,8 @@ pub enum Error {
     PrepareQueries(#[from] crate::prepare_queries::error::Error),
     /// An error while reading PostgreSQL schema files.
     LoadSchema(#[from] crate::load_schema::error::Error),
-    /// An error while trying to write the generated code to its destination file.
-    WriteCodeGenFile(#[from] WriteOutputError),
+    /// An error while trying to write the generated crate to its destination.
+    PersistCrate(#[from] PersistError),
 }
 
 impl Error {
@@ -39,8 +39,17 @@ impl Error {
 }
 
 #[derive(Debug, ThisError, Diagnostic)]
-#[error("Could not write your queries to destination file `{file_path}`: ({err})")]
-pub struct WriteOutputError {
+#[error("Could not perform IO on file `{file_path}`: ({err})")]
+pub struct PersistError {
     pub(crate) file_path: PathBuf,
     pub(crate) err: std::io::Error,
 }
+
+impl PersistError {
+    pub fn wrap(path: impl Into<PathBuf>) -> impl FnOnce(std::io::Error) -> PersistError {
+        |err| PersistError {
+            file_path: path.into(),
+            err,
+        }
+    }
+}

crates/cornucopia/src/lib.rs

@@ -58,7 +58,7 @@ pub fn gen_live<P: AsRef<Path>>(
         settings,
     );
     // Write
-    generated.persist(destination).expect("TODO error handling");
+    generated.persist(destination)?;
 
     Ok(())
 }
@@ -92,7 +92,7 @@ pub fn gen_managed<P: AsRef<Path>>(
     );
     container::cleanup(podman)?;
     // Write
-    generated.persist(destination).expect("TODO error handling");
+    generated.persist(destination)?;
 
     Ok(())
 }