An enum and backticks for lookahead error

crates/uv-requirements/src/lookahead.rs

@@ -1,11 +1,11 @@
 use std::collections::VecDeque;
 
-use anyhow::{Context, Result};
 use futures::stream::FuturesUnordered;
 use futures::StreamExt;
 use rustc_hash::FxHashSet;
+use thiserror::Error;
 
-use distribution_types::{Dist, DistributionMetadata, LocalEditable};
+use distribution_types::{BuiltDist, Dist, DistributionMetadata, LocalEditable, SourceDist};
 use pep508_rs::{MarkerEnvironment, Requirement, VersionOrUrl};
 use pypi_types::Metadata23;
 use uv_client::RegistryClient;
@@ -14,6 +14,16 @@ use uv_distribution::{DistributionDatabase, Reporter};
 use uv_resolver::{InMemoryIndex, MetadataResponse};
 use uv_types::{BuildContext, HashStrategy, RequestedRequirements};
 
+#[derive(Debug, Error)]
+pub enum LookaheadError {
+    #[error("Failed to download: `{0}`")]
+    Download(BuiltDist, #[source] uv_distribution::Error),
+    #[error("Failed to download and build: `{0}`")]
+    DownloadAndBuild(SourceDist, #[source] uv_distribution::Error),
+    #[error(transparent)]
+    UnsupportedUrl(#[from] distribution_types::Error),
+}
+
 /// A resolver for resolving lookahead requirements from direct URLs.
 ///
 /// The resolver extends certain privileges to "first-party" requirements. For example, first-party
@@ -81,7 +91,10 @@ impl<'a, Context: BuildContext + Send + Sync> LookaheadResolver<'a, Context> {
     }
 
     /// Resolve the requirements from the provided source trees.
-    pub async fn resolve(self, markers: &MarkerEnvironment) -> Result<Vec<RequestedRequirements>> {
+    pub async fn resolve(
+        self,
+        markers: &MarkerEnvironment,
+    ) -> Result<Vec<RequestedRequirements>, LookaheadError> {
         let mut results = Vec::new();
         let mut futures = FuturesUnordered::new();
         let mut seen = FxHashSet::default();
@@ -127,7 +140,10 @@ impl<'a, Context: BuildContext + Send + Sync> LookaheadResolver<'a, Context> {
     }
 
     /// Infer the package name for a given "unnamed" requirement.
-    async fn lookahead(&self, requirement: Requirement) -> Result<Option<RequestedRequirements>> {
+    async fn lookahead(
+        &self,
+        requirement: Requirement,
+    ) -> Result<Option<RequestedRequirements>, LookaheadError> {
         // Determine whether the requirement represents a local distribution.
         let Some(VersionOrUrl::Url(url)) = requirement.version_or_url.as_ref() else {
             return Ok(None);
@@ -159,9 +175,11 @@ impl<'a, Context: BuildContext + Send + Sync> LookaheadResolver<'a, Context> {
                     .database
                     .get_or_build_wheel_metadata(&dist, self.hasher.get(&dist))
                     .await
-                    .with_context(|| match &dist {
-                        Dist::Built(built) => format!("Failed to download: {built}"),
-                        Dist::Source(source) => format!("Failed to download and build: {source}"),
+                    .map_err(|err| match &dist {
+                        Dist::Built(built) => LookaheadError::Download(built.clone(), err),
+                        Dist::Source(source) => {
+                            LookaheadError::DownloadAndBuild(source.clone(), err)
+                        }
                     })?;
 
                 let requires_dist = archive.metadata.requires_dist.clone();

crates/uv/src/commands/pip_install.rs

@@ -1114,6 +1114,9 @@ enum Error {
     #[error(transparent)]
     Fmt(#[from] std::fmt::Error),
 
+    #[error(transparent)]
+    Lookahead(#[from] uv_requirements::LookaheadError),
+
     #[error(transparent)]
     Anyhow(#[from] anyhow::Error),
 }

crates/uv/src/commands/run.rs

@@ -689,6 +689,9 @@ enum Error {
     #[error(transparent)]
     Fmt(#[from] std::fmt::Error),
 
+    #[error(transparent)]
+    Lookahead(#[from] uv_requirements::LookaheadError),
+
     #[error(transparent)]
     Anyhow(#[from] anyhow::Error),
 }

crates/uv/tests/pip_compile.rs

@@ -1366,7 +1366,7 @@ fn compile_git_mismatched_name() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download and build: dask @ git+https://github.com/pallets/flask.git@3.0.0
+    error: Failed to download and build: `dask @ git+https://github.com/pallets/flask.git@3.0.0`
       Caused by: Package metadata name `flask` does not match given name `dask`
     "###
     );
@@ -3413,7 +3413,7 @@ fn compile_html() -> Result<()> {
     # This file was autogenerated by uv via the following command:
     #    uv pip compile requirements.in --cache-dir [CACHE_DIR]
     jinja2==3.1.2
-    markupsafe==2.1.3
+    markupsafe==2.1.5
         # via jinja2
 
     ----- stderr -----
@@ -4742,7 +4742,7 @@ fn offline_direct_url() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download: iniconfig @ https://files.pythonhosted.org/packages/ef/a6/62565a6e1cf69e10f5727360368e451d4b7f58beeac6173dc9db836a5b46/iniconfig-2.0.0-py3-none-any.whl
+    error: Failed to download: `iniconfig @ https://files.pythonhosted.org/packages/ef/a6/62565a6e1cf69e10f5727360368e451d4b7f58beeac6173dc9db836a5b46/iniconfig-2.0.0-py3-none-any.whl`
       Caused by: Network connectivity is disabled, but the requested data wasn't found in the cache for: `https://files.pythonhosted.org/packages/ef/a6/62565a6e1cf69e10f5727360368e451d4b7f58beeac6173dc9db836a5b46/iniconfig-2.0.0-py3-none-any.whl`
     "###
     );
@@ -6349,7 +6349,7 @@ fn not_found_direct_url() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download: iniconfig @ https://files.pythonhosted.org/packages/ef/a6/fake/iniconfig-2.0.0-py3-none-any.whl
+    error: Failed to download: `iniconfig @ https://files.pythonhosted.org/packages/ef/a6/fake/iniconfig-2.0.0-py3-none-any.whl`
       Caused by: HTTP status client error (404 Not Found) for url (https://files.pythonhosted.org/packages/ef/a6/fake/iniconfig-2.0.0-py3-none-any.whl)
     "###
     );
@@ -7737,7 +7737,7 @@ fn compile_index_url_fallback_prefer_primary() -> Result<()> {
     ----- stdout -----
     # This file was autogenerated by uv via the following command:
     #    uv pip compile --cache-dir [CACHE_DIR] --index-strategy unsafe-any-match requirements.in --no-deps
-    jinja2==3.1.2
+    jinja2==3.1.3
 
     ----- stderr -----
     Resolved 1 package in [TIME]

crates/uv/tests/pip_install.rs

@@ -1071,7 +1071,7 @@ fn install_git_public_https_missing_branch_or_tag() {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download and build: uv-public-pypackage @ git+https://github.com/astral-test/uv-public-pypackage@2.0.0
+    error: Failed to download and build: `uv-public-pypackage @ git+https://github.com/astral-test/uv-public-pypackage@2.0.0`
       Caused by: Git operation failed
       Caused by: failed to clone into: [CACHE_DIR]/git-v0/db/8dab139913c4b566
       Caused by: failed to fetch branch or tag `2.0.0`
@@ -1108,7 +1108,7 @@ fn install_git_public_https_missing_commit() {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download and build: uv-public-pypackage @ git+https://github.com/astral-test/uv-public-pypackage@79a935a7a1a0ad6d0bdf72dce0e16cb0a24a1b3b
+    error: Failed to download and build: `uv-public-pypackage @ git+https://github.com/astral-test/uv-public-pypackage@79a935a7a1a0ad6d0bdf72dce0e16cb0a24a1b3b`
       Caused by: Git operation failed
       Caused by: failed to clone into: [CACHE_DIR]/git-v0/db/8dab139913c4b566
       Caused by: failed to fetch commit `79a935a7a1a0ad6d0bdf72dce0e16cb0a24a1b3b`
@@ -1317,7 +1317,7 @@ fn install_git_private_https_pat_not_authorized() {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download and build: uv-private-pypackage @ git+https://git:***@github.com/astral-test/uv-private-pypackage
+    error: Failed to download and build: `uv-private-pypackage @ git+https://git:***@github.com/astral-test/uv-private-pypackage`
       Caused by: Git operation failed
       Caused by: failed to clone into: [CACHE_DIR]/git-v0/db/8401f5508e3e612d
       Caused by: process didn't exit successfully: `git fetch --force --update-head-ok 'https://git:***@github.com/astral-test/uv-private-pypackage' '+HEAD:refs/remotes/origin/HEAD'` (exit status: 128)
@@ -2625,7 +2625,7 @@ fn no_build_isolation() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    error: Failed to download and build: anyio @ https://files.pythonhosted.org/packages/db/4d/3970183622f0330d3c23d9b8a5f52e365e50381fd484d08e3285104333d3/anyio-4.3.0.tar.gz
+    error: Failed to download and build: `anyio @ https://files.pythonhosted.org/packages/db/4d/3970183622f0330d3c23d9b8a5f52e365e50381fd484d08e3285104333d3/anyio-4.3.0.tar.gz`
       Caused by: Failed to build: `anyio @ https://files.pythonhosted.org/packages/db/4d/3970183622f0330d3c23d9b8a5f52e365e50381fd484d08e3285104333d3/anyio-4.3.0.tar.gz`
       Caused by: Build backend failed to determine metadata through `prepare_metadata_for_build_wheel` with exit status: 1
     --- stdout: