fix(resolver): In errors, show rejected versions over alt versions

The user likely intended what they said and we should tell them why it didn't work. Rejected versions also imply alt versions below them. Fixes rust-lang#4260
epage · Dec 11, 2024 · 6d116f3 · 6d116f3
1 parent 784dfbe
commit 6d116f3
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Showing 2 changed files with 49 additions and 51 deletions.
diff --git a/src/cargo/core/resolver/errors.rs b/src/cargo/core/resolver/errors.rs
@@ -221,7 +221,51 @@ pub(super) fn activation_error(
     // give an error message that nothing was found.
     let mut msg = String::new();
     let mut hints = String::new();
-    if let Some(candidates) = alt_versions(registry, dep) {
+    if let Some(version_candidates) = rejected_versions(registry, dep) {
+        let version_candidates = match version_candidates {
+            Ok(c) => c,
+            Err(e) => return to_resolve_err(e),
+        };
+        let _ = writeln!(
+            &mut msg,
+            "no matching versions for `{}` found",
+            dep.package_name()
+        );
+        for candidate in version_candidates {
+            match candidate {
+                IndexSummary::Candidate(summary) => {
+                    // HACK: If this was a real candidate, we wouldn't hit this case.
+                    // so it must be a patch which get normalized to being a candidate
+                    let _ = writeln!(&mut msg, "  version {} is unavailable", summary.version());
+                }
+                IndexSummary::Yanked(summary) => {
+                    let _ = writeln!(&mut msg, "  version {} is yanked", summary.version());
+                }
+                IndexSummary::Offline(summary) => {
+                    let _ = writeln!(&mut msg, "  version {} is not cached", summary.version());
+                }
+                IndexSummary::Unsupported(summary, schema_version) => {
+                    if let Some(rust_version) = summary.rust_version() {
+                        // HACK: technically its unsupported and we shouldn't make assumptions
+                        // about the entry but this is limited and for diagnostics purposes
+                        let _ = writeln!(
+                            &mut msg,
+                            "  version {} requires cargo {}",
+                            summary.version(),
+                            rust_version
+                        );
+                    } else {
+                        let _ = writeln!(
+                            &mut msg,
+                            "  version {} requires a Cargo version that supports index version {}",
+                            summary.version(),
+                            schema_version
+                        );
+                    }
+                }
+            }
+        }
+    } else if let Some(candidates) = alt_versions(registry, dep) {
         let candidates = match candidates {
             Ok(c) => c,
             Err(e) => return to_resolve_err(e),
@@ -286,50 +330,6 @@ pub(super) fn activation_error(
                 "\nperhaps a crate was updated and forgotten to be re-vendored?"
             );
         }
-    } else if let Some(version_candidates) = rejected_versions(registry, dep) {
-        let version_candidates = match version_candidates {
-            Ok(c) => c,
-            Err(e) => return to_resolve_err(e),
-        };
-        let _ = writeln!(
-            &mut msg,
-            "no matching versions for `{}` found",
-            dep.package_name()
-        );
-        for candidate in version_candidates {
-            match candidate {
-                IndexSummary::Candidate(summary) => {
-                    // HACK: If this was a real candidate, we wouldn't hit this case.
-                    // so it must be a patch which get normalized to being a candidate
-                    let _ = writeln!(&mut msg, "  version {} is unavailable", summary.version());
-                }
-                IndexSummary::Yanked(summary) => {
-                    let _ = writeln!(&mut msg, "  version {} is yanked", summary.version());
-                }
-                IndexSummary::Offline(summary) => {
-                    let _ = writeln!(&mut msg, "  version {} is not cached", summary.version());
-                }
-                IndexSummary::Unsupported(summary, schema_version) => {
-                    if let Some(rust_version) = summary.rust_version() {
-                        // HACK: technically its unsupported and we shouldn't make assumptions
-                        // about the entry but this is limited and for diagnostics purposes
-                        let _ = writeln!(
-                            &mut msg,
-                            "  version {} requires cargo {}",
-                            summary.version(),
-                            rust_version
-                        );
-                    } else {
-                        let _ = writeln!(
-                            &mut msg,
-                            "  version {} requires a Cargo version that supports index version {}",
-                            summary.version(),
-                            schema_version
-                        );
-                    }
-                }
-            }
-        }
     } else if let Some(name_candidates) = alt_names(registry, dep) {
         let name_candidates = match name_candidates {
             Ok(c) => c,

diff --git a/tests/testsuite/registry.rs b/tests/testsuite/registry.rs
@@ -862,12 +862,11 @@ fn relying_on_a_yank_is_bad_http() {
     let _server = setup_http();
     relying_on_a_yank_is_bad(str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] failed to select a version for the requirement `baz = "=0.0.2"`
-candidate versions found which didn't match: 0.0.1
+[ERROR] no matching versions for `baz` found
+  version 0.0.2 is yanked
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `bar v0.0.1`
     ... which satisfies dependency `bar = "*"` of package `foo v0.0.1 ([ROOT]/foo)`
-perhaps a crate was updated and forgotten to be re-vendored?
 
 "#]]);
 }
@@ -876,12 +875,11 @@ perhaps a crate was updated and forgotten to be re-vendored?
 fn relying_on_a_yank_is_bad_git() {
     relying_on_a_yank_is_bad(str![[r#"
 [UPDATING] `dummy-registry` index
-[ERROR] failed to select a version for the requirement `baz = "=0.0.2"`
-candidate versions found which didn't match: 0.0.1
+[ERROR] no matching versions for `baz` found
+  version 0.0.2 is yanked
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `bar v0.0.1`
     ... which satisfies dependency `bar = "*"` of package `foo v0.0.1 ([ROOT]/foo)`
-perhaps a crate was updated and forgotten to be re-vendored?
 
 "#]]);
 }