Use a dedicated error type for `puffin-distribution` (#466)

Cargo.lock

@@ -2541,6 +2541,7 @@ dependencies = [
  "pypi-types",
  "rayon",
  "tempfile",
+ "thiserror",
  "tokio",
  "tokio-util",
  "tracing",

crates/install-wheel-rs/src/lib.rs

@@ -65,6 +65,10 @@ pub enum Error {
     Pep440,
     #[error("Invalid direct_url.json")]
     DirectUrlJson(#[from] serde_json::Error),
+    #[error("No .dist-info directory found")]
+    MissingDistInfo,
+    #[error("Multiple .dist-info directories found: {0}")]
+    MultipleDistInfo(String),
 }
 
 impl Error {
@@ -84,7 +88,7 @@ impl Error {
 pub fn find_dist_info<'a, T: Copy>(
     filename: &WheelFilename,
     files: impl Iterator<Item = (T, &'a str)>,
-) -> Result<(T, &'a str), String> {
+) -> Result<(T, &'a str), Error> {
     let metadatas: Vec<_> = files
         .filter_map(|(payload, path)| {
             let (dist_info_dir, file) = path.split_once('/')?;
@@ -102,17 +106,16 @@ pub fn find_dist_info<'a, T: Copy>(
         .collect();
     let (payload, dist_info_dir) = match metadatas[..] {
         [] => {
-            return Err("no .dist-info directory".to_string());
+            return Err(Error::MissingDistInfo);
         }
         [(payload, path)] => (payload, path),
         _ => {
-            return Err(format!(
+            return Err(Error::MultipleDistInfo(
-                "multiple .dist-info directories: {}",
                 metadatas
                     .into_iter()
                     .map(|(_, dist_info_dir)| dist_info_dir.to_string())
                     .collect::<Vec<_>>()
-                    .join(", ")
+                    .join(", "),
             ));
         }
     };

crates/install-wheel-rs/src/wheel.rs

@@ -930,8 +930,7 @@ pub fn install_wheel(
         ZipArchive::new(reader).map_err(|err| Error::from_zip_error("(index)".to_string(), err))?;
 
     debug!(name = name.as_ref(), "Getting wheel metadata");
-    let dist_info_prefix = find_dist_info(filename, archive.file_names().map(|name| (name, name)))
+    let dist_info_prefix = find_dist_info(filename, archive.file_names().map(|name| (name, name)))?
-        .map_err(Error::InvalidWheel)?
         .1
         .to_string();
     let (name, _version) = read_metadata(&dist_info_prefix, &mut archive)?;

crates/puffin-client/src/client.rs

@@ -301,8 +301,7 @@ impl RegistryClient {
                 .iter()
                 .enumerate()
                 .filter_map(|(idx, e)| Some((idx, e.entry().filename().as_str().ok()?))),
-        )
+        )?;
-        .map_err(|err| Error::InvalidDistInfo(filename.clone(), err))?;
 
         // Read the contents of the METADATA file
         let mut contents = Vec::new();

crates/puffin-client/src/error.rs

@@ -13,6 +13,9 @@ pub enum Error {
     #[error(transparent)]
     UrlParseError(#[from] url::ParseError),
 
+    #[error(transparent)]
+    InstallWheel(#[from] install_wheel_rs::Error),
+
     #[error("{0} isn't available locally, but making network requests to registries was banned.")]
     NoIndex(String),
 

crates/puffin-client/src/remote_metadata.rs

@@ -76,8 +76,7 @@ pub(crate) async fn wheel_metadata_from_remote_zip(
             .iter()
             .enumerate()
             .filter_map(|(idx, e)| Some(((idx, e), e.entry().filename().as_str().ok()?))),
-    )
+    )?;
-    .map_err(|err| Error::InvalidDistInfo(filename.clone(), err))?;
 
     let offset = metadata_entry.header_offset();
     let size = metadata_entry.entry().compressed_size()

crates/puffin-distribution/Cargo.toml

@@ -24,6 +24,7 @@ bytesize = { workspace = true }
 fs-err = { workspace = true }
 rayon = { workspace = true }
 tempfile = { workspace = true }
+thiserror = { workspace = true }
 tokio = { workspace = true }
 tokio-util = { workspace = true, features = ["compat"] }
 tracing = { workspace = true }

crates/puffin-distribution/src/download.rs

@@ -1,7 +1,7 @@
 use std::path::PathBuf;
 use std::str::FromStr;
 
-use anyhow::{format_err, Context, Result};
+use anyhow::{Context, Result};
 use tempfile::TempDir;
 use zip::ZipArchive;
 
@@ -10,6 +10,8 @@ use distribution_types::{Dist, RemoteSource};
 use install_wheel_rs::find_dist_info;
 use pypi_types::Metadata21;
 
+use crate::error::Error;
+
 /// A downloaded wheel that's stored in-memory.
 #[derive(Debug)]
 pub struct InMemoryWheel {
@@ -86,12 +88,14 @@ impl std::fmt::Display for SourceDistDownload {
 
 impl InMemoryWheel {
     /// Read the [`Metadata21`] from a wheel.
-    pub fn read_dist_info(&self) -> Result<Metadata21> {
+    pub fn read_dist_info(&self) -> Result<Metadata21, Error> {
         let mut archive = ZipArchive::new(std::io::Cursor::new(&self.buffer))?;
-        let filename = self.filename()?;
+        let filename = self
+            .filename()
+            .map_err(|err| Error::FilenameParse(self.dist.to_string(), err))?;
         let dist_info_dir =
             find_dist_info(&filename, archive.file_names().map(|name| (name, name)))
-                .map_err(|err| format_err!("Invalid wheel {filename}: {err}"))?
+                .map_err(|err| Error::DistInfo(self.dist.to_string(), err))?
                 .1;
         let dist_info =
             std::io::read_to_string(archive.by_name(&format!("{dist_info_dir}/METADATA"))?)?;
@@ -101,12 +105,14 @@ impl InMemoryWheel {
 
 impl DiskWheel {
     /// Read the [`Metadata21`] from a wheel.
-    pub fn read_dist_info(&self) -> Result<Metadata21> {
+    pub fn read_dist_info(&self) -> Result<Metadata21, Error> {
         let mut archive = ZipArchive::new(fs_err::File::open(&self.path)?)?;
-        let filename = self.filename()?;
+        let filename = self
+            .filename()
+            .map_err(|err| Error::FilenameParse(self.dist.to_string(), err))?;
         let dist_info_dir =
             find_dist_info(&filename, archive.file_names().map(|name| (name, name)))
-                .map_err(|err| format_err!("Invalid wheel {filename}: {err}"))?
+                .map_err(|err| Error::DistInfo(self.dist.to_string(), err))?
                 .1;
         let dist_info =
             std::io::read_to_string(archive.by_name(&format!("{dist_info_dir}/METADATA"))?)?;
@@ -116,7 +122,7 @@ impl DiskWheel {
 
 impl WheelDownload {
     /// Read the [`Metadata21`] from a wheel.
-    pub fn read_dist_info(&self) -> Result<Metadata21> {
+    pub fn read_dist_info(&self) -> Result<Metadata21, Error> {
         match self {
             WheelDownload::InMemory(wheel) => wheel.read_dist_info(),
             WheelDownload::Disk(wheel) => wheel.read_dist_info(),

crates/puffin-distribution/src/error.rs

@@ -0,0 +1,13 @@
+#[derive(thiserror::Error, Debug)]
+pub enum Error {
+    #[error(transparent)]
+    IO(#[from] std::io::Error),
+    #[error(transparent)]
+    PypiTypes(#[from] pypi_types::Error),
+    #[error(transparent)]
+    Zip(#[from] zip::result::ZipError),
+    #[error("Unable to read .dist-info directory for: {0}")]
+    DistInfo(String, #[source] install_wheel_rs::Error),
+    #[error("Unable to parse wheel filename for: {0}")]
+    FilenameParse(String, #[source] anyhow::Error),
+}

crates/puffin-distribution/src/fetcher.rs

@@ -18,6 +18,7 @@ use puffin_git::{GitSource, GitUrl};
 use puffin_traits::BuildContext;
 use pypi_types::Metadata21;
 
+use crate::error::Error;
 use crate::reporter::Facade;
 use crate::{DiskWheel, Download, InMemoryWheel, Reporter, SourceDistDownload, WheelDownload};
 
@@ -52,7 +53,7 @@ impl<'a> Fetcher<'a> {
     }
 
     /// Return the [`Metadata21`] for a distribution, if it exists in the cache.
-    pub fn find_metadata(&self, dist: &Dist, tags: &Tags) -> Result<Option<Metadata21>> {
+    pub fn find_metadata(&self, dist: &Dist, tags: &Tags) -> Result<Option<Metadata21>, Error> {
         self.find_in_cache(dist, tags)
             .map(|wheel| wheel.read_dist_info())
             .transpose()
@@ -77,10 +78,14 @@ impl<'a> Fetcher<'a> {
             // Fetch the distribution, then read the metadata (for built distributions), or build
             // the distribution and _then_ read the metadata (for source distributions).
             dist => match self.fetch_dist(dist, client).await? {
-                Download::Wheel(wheel) => wheel.read_dist_info(),
+                Download::Wheel(wheel) => {
+                    let metadata = wheel.read_dist_info()?;
+                    Ok(metadata)
+                }
                 Download::SourceDist(sdist) => {
                     let wheel = self.build_sdist(sdist, build_context).await?;
-                    wheel.read_dist_info()
+                    let metadata = wheel.read_dist_info()?;
+                    Ok(metadata)
                 }
             },
         }

crates/puffin-distribution/src/lib.rs

@@ -4,6 +4,7 @@ pub use crate::reporter::Reporter;
 pub use crate::unzip::Unzip;
 
 mod download;
+mod error;
 mod fetcher;
 mod reporter;
 mod unzip;