Improve error message when git ref cannot be fetched (#1826)

Follow-up to #1781 improving the error message when a ref cannot be
fetched

crates/uv-git/src/git.rs

@@ -6,12 +6,12 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::{env, str};
 
-use anyhow::{anyhow, Context as _, Result};
+use anyhow::{anyhow, Context, Result};
 use cargo_util::{paths, ProcessBuilder};
 use git2::{self, ErrorClass, ObjectType};
 use reqwest::Client;
 use reqwest::StatusCode;
-use tracing::{debug, error, warn};
+use tracing::{debug, warn};
 use url::Url;
 use uv_fs::Normalized;
 
@@ -78,6 +78,18 @@ impl GitReference {
             GitReference::DefaultBranch => "HEAD",
         }
     }
+
+    pub(crate) fn kind_str(&self) -> &str {
+        match self {
+            GitReference::Branch(_) => "branch",
+            GitReference::Tag(_) => "tag",
+            GitReference::BranchOrTag(_) => "branch or tag",
+            GitReference::FullCommit(_) => "commit",
+            GitReference::ShortCommit(_) => "short commit",
+            GitReference::Ref(_) => "ref",
+            GitReference::DefaultBranch => "default branch",
+        }
+    }
 }
 
 /// A short abbreviated OID.
@@ -245,6 +257,7 @@ impl GitDatabase {
 impl GitReference {
     /// Resolves self to an object ID with objects the `repo` currently has.
     pub(crate) fn resolve(&self, repo: &git2::Repository) -> Result<git2::Oid> {
+        let refkind = self.kind_str();
         let id = match self {
             // Note that we resolve the named tag here in sync with where it's
             // fetched into via `fetch` below.
@@ -255,7 +268,7 @@ impl GitReference {
                 let obj = obj.peel(ObjectType::Commit)?;
                 Ok(obj.id())
             })()
-            .with_context(|| format!("failed to find tag `{s}`"))?,
+            .with_context(|| format!("failed to find {refkind} `{s}`"))?,
 
             // Resolve the remote name since that's all we're configuring in
             // `fetch` below.
@@ -263,10 +276,10 @@ impl GitReference {
                 let name = format!("origin/{s}");
                 let b = repo
                     .find_branch(&name, git2::BranchType::Remote)
-                    .with_context(|| format!("failed to find branch `{s}`"))?;
+                    .with_context(|| format!("failed to find {refkind} `{s}`"))?;
                 b.get()
                     .target()
-                    .ok_or_else(|| anyhow::format_err!("branch `{s}` did not have a target"))?
+                    .ok_or_else(|| anyhow::format_err!("{refkind} `{s}` did not have a target"))?
             }
 
             // Attempt to resolve the branch, then the tag.
@@ -283,7 +296,7 @@ impl GitReference {
                         let obj = obj.peel(ObjectType::Commit).ok()?;
                         Some(obj.id())
                     })
-                    .ok_or_else(|| anyhow::format_err!("failed to find branch or tag `{s}`"))?
+                    .ok_or_else(|| anyhow::format_err!("failed to find {refkind} `{s}`"))?
             }
 
             // We'll be using the HEAD commit
@@ -980,36 +993,50 @@ pub(crate) fn fetch(
     debug!("Performing a Git fetch for: {remote_url}");
     match strategy {
         FetchStrategy::Cli => {
-            match refspec_strategy {
+            let result = match refspec_strategy {
                 RefspecStrategy::All => fetch_with_cli(repo, remote_url, refspecs.as_slice(), tags),
                 RefspecStrategy::First => {
-                    let num_refspecs = refspecs.len();
-
                     // Try each refspec
-                    let errors = refspecs
+                    let mut errors = refspecs
-                        .into_iter()
+                        .iter()
-                        .map(|refspec| {
+                        .map_while(|refspec| {
-                            (
+                            let fetch_result =
-                                refspec.clone(),
+                                fetch_with_cli(repo, remote_url, &[refspec.clone()], tags);
-                                fetch_with_cli(repo, remote_url, &[refspec], tags),
+
-                            )
+                            // Stop after the first success and log failures
+                            match fetch_result {
+                                Err(ref err) => {
+                                    debug!("failed to fetch refspec `{refspec}`: {err}");
+                                    Some(fetch_result)
+                                }
+                                Ok(()) => None,
+                            }
                         })
-                        // Stop after the first success
-                        .take_while(|(_, result)| result.is_err())
                         .collect::<Vec<_>>();
 
-                    if errors.len() == num_refspecs {
+                    if errors.len() == refspecs.len() {
-                        // If all of the fetches failed, report to the user
+                        if let Some(result) = errors.pop() {
-                        for (refspec, err) in errors {
+                            // Use the last error for the message
-                            if let Err(err) = err {
+                            result
-                                error!("failed to fetch refspec `{refspec}`: {err}");
+                        } else {
+                            // Can only occur if there were no refspecs to fetch
+                            Ok(())
                         }
-                        }
-                        Err(anyhow!("failed to fetch all refspecs"))
                     } else {
                         Ok(())
                     }
                 }
+            };
+            match reference {
+                // With the default branch, adding context is confusing
+                GitReference::DefaultBranch => result,
+                _ => result.with_context(|| {
+                    format!(
+                        "failed to fetch {} `{}`",
+                        reference.kind_str(),
+                        reference.as_str()
+                    )
+                }),
             }
         }
         FetchStrategy::Libgit2 => {

crates/uv/tests/common/mod.rs

@@ -148,15 +148,15 @@ impl TestContext {
         ]
     }
 
-    /// Canonical snapshot filters for this test context.
+    /// Standard snapshot filters _plus_ those for this test context.
     pub fn filters(&self) -> Vec<(&str, &str)> {
-        let mut filters = INSTA_FILTERS.to_vec();
+        // Put test context snapshots before the default filters
-
+        // This ensures we don't replace other patterns inside paths from the test context first
-        for (pattern, replacement) in &self.filters {
+        self.filters
-            filters.push((pattern, replacement));
+            .iter()
-        }
+            .map(|(p, r)| (p.as_str(), r.as_str()))
-
+            .chain(INSTA_FILTERS.iter().copied())
-        filters
+            .collect()
     }
 }
 

crates/uv/tests/pip_install.rs

@@ -815,10 +815,15 @@ fn install_git_public_https() {
 /// Install a package from a public GitHub repository at a ref that does not exist
 #[test]
 #[cfg(feature = "git")]
-fn install_git_public_https_missing_ref() {
+fn install_git_public_https_missing_branch_or_tag() {
     let context = TestContext::new("3.8");
 
-    uv_snapshot!(context.filters(), command(&context)
+    let mut filters = context.filters();
+    // Windows does not style the command the same as Unix, so we must omit it from the snapshot
+    filters.push(("`git fetch .*`", "`git fetch [...]`"));
+    filters.push(("exit status", "exit code"));
+
+    uv_snapshot!(filters, command(&context)
         // 2.0.0 does not exist
         .arg("uv-public-pypackage @ git+https://github.com/astral-test/uv-public-pypackage@2.0.0")
         , @r###"
@@ -830,7 +835,42 @@ fn install_git_public_https_missing_ref() {
     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 all refspecs
+      Caused by: failed to fetch branch or tag `2.0.0`
+      Caused by: process didn't exit successfully: `git fetch [...]` (exit code: 128)
+    --- stderr
+    fatal: couldn't find remote ref refs/tags/2.0.0
+
+    "###);
+}
+
+/// Install a package from a public GitHub repository at a ref that does not exist
+#[test]
+#[cfg(feature = "git")]
+fn install_git_public_https_missing_commit() {
+    let context = TestContext::new("3.8");
+
+    let mut filters = context.filters();
+    // Windows does not style the command the same as Unix, so we must omit it from the snapshot
+    filters.push(("`git fetch .*`", "`git fetch [...]`"));
+    filters.push(("exit status", "exit code"));
+
+    uv_snapshot!(filters, command(&context)
+        // 2.0.0 does not exist
+        .arg("uv-public-pypackage @ git+https://github.com/astral-test/uv-public-pypackage@79a935a7a1a0ad6d0bdf72dce0e16cb0a24a1b3b")
+        , @r###"
+    success: false
+    exit_code: 2
+    ----- stdout -----
+
+    ----- stderr -----
+    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`
+      Caused by: process didn't exit successfully: `git fetch [...]` (exit code: 128)
+    --- stderr
+    fatal: remote error: upload-pack: not our ref 79a935a7a1a0ad6d0bdf72dce0e16cb0a24a1b3b
+
     "###);
 }