Avoid subsequent index hint when no versions are available on the first index

Author: zanieb

crates/uv-resolver/src/pubgrub/report.rs

@@ -725,12 +725,18 @@ impl PubGrubReportFormatter<'_> {
                     .skip_while(|url| *url != found_index)
                     .nth(1)
                 {
-                    hints.insert(PubGrubHint::UncheckedIndex {
-                        package: package.clone(),
-                        range: set.clone(),
-                        found_index: found_index.clone(),
-                        next_index: next_index.clone(),
-                    });
+                    // Do not include the hint if the set is "all versions"
+                    if !set
+                        .iter()
+                        .all(|range| matches!(range, (Bound::Unbounded, Bound::Unbounded)))
+                    {
+                        hints.insert(PubGrubHint::UncheckedIndex {
+                            package: package.clone(),
+                            range: set.clone(),
+                            found_index: found_index.clone(),
+                            next_index: next_index.clone(),
+                        });
+                    }
                 }
             }
         }

crates/uv/tests/it/pip_compile.rs

@@ -11659,6 +11659,37 @@ fn compile_index_url_first_match() -> Result<()> {
     Ok(())
 }
 
+/// Install a package via `--extra-index-url`.
+///
+/// If the package exists on the "extra" index, but at an incompatible version, the resolution
+/// should fail by default (even though a compatible version exists on the "primary" index).
+#[test]
+fn compile_index_url_first_match_all_versions() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let requirements_in = context.temp_dir.child("requirements.in");
+    requirements_in.write_str("some-package-not-on-the-index")?;
+
+    uv_snapshot!(context.filters(), context.pip_compile()
+        .arg("--index-url")
+        .arg("https://pypi.org/simple")
+        .arg("--extra-index-url")
+        .arg("https://test.pypi.org/simple")
+        .arg("requirements.in")
+        .arg("--no-deps"), @r###"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+
+    ----- stderr -----
+      × No solution found when resolving dependencies:
+      ╰─▶ Because some-package-not-on-the-index was not found in the package registry and you require some-package-not-on-the-index, we can conclude that your requirements are unsatisfiable.
+    "###
+    );
+
+    Ok(())
+}
+
 /// Install a package via `--extra-index-url`.
 ///
 /// If the package exists exist on the "extra" index, but at an incompatible version, the