fix(resolver): Better match rustc in error styling (#16795)

### What does this PR try to resolve?

The original motivation was to find ways to make some of the suggestions
stand out more but we generally had a wording and organization mismatch
with rustc

See [#t-cargo > wrong missing feature reported with
`target`-gated deps @
💬](https://rust-lang.zulipchat.com/#narrow/channel/246057-t-cargo/topic/wrong.20missing.20feature.20reported.20with.20.60target.60-gated.20deps/near/581695948)

### How to test and review this PR?

Author: weihanglo

Cargo.lock

@@ -10,6 +10,7 @@ cargo-platform.workspace = true
 cargo-util-schemas.workspace = true
 cargo-util.workspace = true
 proptest.workspace = true
+snapbox.workspace = true
 varisat.workspace = true
 
 [lints]

crates/resolver-tests/Cargo.toml

@@ -1,6 +1,8 @@
 use cargo::core::Dependency;
 use cargo::core::dependency::DepKind;
 use cargo::util::GlobalContext;
+use snapbox::assert_data_eq;
+use snapbox::str;
 
 use resolver_tests::{
     helpers::{
@@ -991,12 +993,15 @@ fn cyclic_good_error_message() {
     let reg = registry(input);
     let error = resolve(vec![dep("A"), dep("B")], &reg).unwrap_err();
     println!("{}", error);
-    assert_eq!("\
+    assert_data_eq!(
+        error.to_string(),
+        str![[r#"
 cyclic package dependency: package `A v0.0.0 (registry `https://example.com/`)` depends on itself. Cycle:
 package `A v0.0.0 (registry `https://example.com/`)`
-    ... which satisfies dependency `A = \"*\"` of package `C v0.0.0 (registry `https://example.com/`)`
-    ... which satisfies dependency `C = \"*\"` of package `A v0.0.0 (registry `https://example.com/`)`\
-", error.to_string());
+    ... which satisfies dependency `A = "*"` of package `C v0.0.0 (registry `https://example.com/`)`
+    ... which satisfies dependency `C = "*"` of package `A v0.0.0 (registry `https://example.com/`)`
+"#]]
+    );
 }
 
 #[test]
@@ -1012,22 +1017,22 @@ fn shortest_path_in_error_message() {
     ];
     let error = resolve(vec![dep("A")], &registry(input)).unwrap_err();
     println!("{}", error);
-    assert_eq!(
-        "\
+    assert_data_eq!(
+        error.to_string(),
+        str![[r#"
 failed to select a version for `F`.
     ... required by package `A v1.0.0 (registry `https://example.com/`)`
-    ... which satisfies dependency `A = \"*\"` of package `root v1.0.0 (registry `https://example.com/`)`
+    ... which satisfies dependency `A = "*"` of package `root v1.0.0 (registry `https://example.com/`)`
 versions that meet the requirements `<=0.1.1` are: 0.1.1, 0.1.0
 
-all possible versions conflict with previously selected packages.
+all possible versions conflict with previously selected packages
 
   previously selected package `F v0.1.2 (registry `https://example.com/`)`
-    ... which satisfies dependency `F = \"^0.1.2\"` of package `E v1.0.0 (registry `https://example.com/`)`
-    ... which satisfies dependency `E = \"*\"` of package `A v1.0.0 (registry `https://example.com/`)`
-    ... which satisfies dependency `A = \"*\"` of package `root v1.0.0 (registry `https://example.com/`)`
+    ... which satisfies dependency `F = "^0.1.2"` of package `E v1.0.0 (registry `https://example.com/`)`
+    ... which satisfies dependency `E = "*"` of package `A v1.0.0 (registry `https://example.com/`)`
+    ... which satisfies dependency `A = "*"` of package `root v1.0.0 (registry `https://example.com/`)`
 
-failed to select a version for `F` which could resolve this conflict\
-    ",
-        error.to_string()
+failed to select a version for `F` which could resolve this conflict
+"#]]
     );
 }

crates/resolver-tests/tests/resolve.rs

@@ -145,10 +145,11 @@ pub(super) fn activation_error(
                     msg.push_str(link);
                     msg.push_str("` as well:\n");
                     msg.push_str(&describe_path_in_context(resolver_ctx, p));
-                    msg.push_str("\nOnly one package in the dependency graph may specify the same links value. This helps ensure that only one copy of a native library is linked in the final binary. ");
-                    msg.push_str("Try to adjust your dependencies so that only one package uses the `links = \"");
+                    msg.push_str("\nnote: only one package in the dependency graph may specify the same links value to ensure that only one copy of a native library is linked in the final binary");
+                    msg.push_str("\nfor more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links");
+                    msg.push_str("\nhelp: try to adjust your dependencies so that only one package uses the `links = \"");
                     msg.push_str(link);
-                    msg.push_str("\"` value. For more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links.");
+                    msg.push_str("\"` value");
                 }
                 ConflictReason::MissingFeature(feature) => {
                     msg.push_str("\n\npackage `");
@@ -162,16 +163,14 @@ pub(super) fn activation_error(
                     msg.push_str("` does not have that feature.\n");
                     let latest = candidates.last().expect("in the non-empty branch");
                     if let Some(closest) = closest(feature, latest.features().keys(), |k| k) {
-                        msg.push_str(" package `");
-                        msg.push_str(&*dep.package_name());
-                        msg.push_str("` does have feature `");
+                        msg.push_str("help: there is a feature `");
                         msg.push_str(closest);
-                        msg.push_str("`\n");
+                        msg.push_str("` with a similar name\n");
                     } else if !latest.features().is_empty() {
                         let mut features: Vec<_> =
                             latest.features().keys().map(|f| f.as_str()).collect();
                         features.sort();
-                        msg.push_str(" available features: ");
+                        msg.push_str("help: available features: ");
                         msg.push_str(&features.join(", "));
                         msg.push_str("\n");
                     }
@@ -188,7 +187,7 @@ pub(super) fn activation_error(
                     msg.push_str(&*dep.package_name());
                     msg.push_str("` does not have that feature.\n");
                     msg.push_str(
-                        " A required dependency with that name exists, \
+                        "note: a required dependency with that name exists, \
                          but only optional dependencies can be used as features.\n",
                     );
                     // p == parent so the full path is redundant.
@@ -204,7 +203,7 @@ pub(super) fn activation_error(
                     msg.push_str(&*dep.package_name());
                     msg.push_str("` does not have that feature.\n");
                     msg.push_str(
-                        " An optional dependency with that name exists, \
+                        "note: an optional dependency with that name exists, \
                          but that dependency uses the \"dep:\" \
                          syntax in the features table, so it does not have an \
                          implicit feature with that name.\n",
@@ -216,7 +215,7 @@ pub(super) fn activation_error(
 
         if has_semver {
             // Group these errors together.
-            msg.push_str("\n\nall possible versions conflict with previously selected packages.");
+            msg.push_str("\n\nall possible versions conflict with previously selected packages");
             for (p, r) in &conflicting_activations {
                 if let ConflictReason::Semver = r {
                     msg.push_str("\n\n  previously selected ");
@@ -336,7 +335,7 @@ pub(super) fn activation_error(
         if let Some(pre) = candidates.iter().find(|c| c.version().is_prerelease()) {
             let _ = write!(
                 &mut hints,
-                "\nif you are looking for the prerelease package it needs to be specified explicitly"
+                "\nhelp: if you are looking for the prerelease package it needs to be specified explicitly"
             );
             let _ = write!(
                 &mut hints,
@@ -352,35 +351,35 @@ pub(super) fn activation_error(
         if dep.source_id().is_path() && dep.version_req().is_locked() {
             let _ = write!(
                 &mut hints,
-                "\nconsider running `cargo update` to update \
-                          a path dependency's locked version",
+                "\nhelp: to update a path dependency's locked version, run `cargo update`",
             );
         }
 
         if registry.is_replaced(dep.source_id()) {
             let _ = write!(
                 &mut hints,
-                "\nperhaps a crate was updated and forgotten to be re-vendored?"
+                "\nnote: perhaps a crate was updated and forgotten to be re-vendored?"
             );
         }
     } else if let Some(name_candidates) = alt_names(registry, dep) {
         let name_candidates = match name_candidates {
             Ok(c) => c,
             Err(e) => return to_resolve_err(e),
         };
-        let _ = writeln!(&mut msg, "no matching package found",);
-        let _ = writeln!(&mut msg, "searched package name: `{}`", dep.package_name());
+        let _ = writeln!(
+            &mut msg,
+            "no matching package named `{}` found",
+            dep.package_name()
+        );
+
         let mut names = name_candidates
             .iter()
             .take(3)
             .map(|c| c.1.name().as_str())
             .collect::<Vec<_>>();
-
         if name_candidates.len() > 3 {
             names.push("...");
         }
-        // Vertically align first suggestion with missing crate name
-        // so a typo jumps out at you.
         let suggestions =
             names
                 .iter()
@@ -390,7 +389,10 @@ pub(super) fn activation_error(
                     i if names.len() - 1 == i && name_candidates.len() <= 3 => acc + " or " + el,
                     _ => acc + ", " + el,
                 });
-        let _ = writeln!(&mut msg, "perhaps you meant:      {suggestions}");
+        let _ = writeln!(
+            &mut hints,
+            "\nhelp: packages with similar names: {suggestions}"
+        );
     } else {
         let _ = writeln!(
             &mut msg,
@@ -414,10 +416,10 @@ pub(super) fn activation_error(
         if let Some(offline_flag) = gctx.offline_flag() {
             let _ = write!(
                 &mut hints,
-                "\nAs a reminder, you're using offline mode ({offline_flag}) \
-                 which can sometimes cause surprising resolution failures, \
-                 if this error is too confusing you may wish to retry \
-                 without `{offline_flag}`.",
+                "\nnote: offline mode (via `{offline_flag}`) \
+                 can sometimes cause surprising resolution failures\
+                 \nhelp: if this error is too confusing you may wish to retry \
+                 without `{offline_flag}`",
             );
         }
     }

src/cargo/core/resolver/errors.rs

@@ -1412,7 +1412,7 @@ fn incompatible_dependencies() {
     ... which satisfies dependency `qux = "^0.1.0"` of package `foo v0.0.1 ([ROOT]/foo)`
 versions that meet the requirements `>=1.0.1` are: 1.0.2, 1.0.1
 
-all possible versions conflict with previously selected packages.
+all possible versions conflict with previously selected packages
 
   previously selected package `bad v1.0.0`
     ... which satisfies dependency `bad = "=1.0.0"` of package `baz v0.1.0`
@@ -1459,7 +1459,7 @@ fn incompatible_dependencies_with_multi_semver() {
     ... required by package `foo v0.0.1 ([ROOT]/foo)`
 versions that meet the requirements `>=1.0.1, <=2.0.0` are: 2.0.0, 1.0.1
 
-all possible versions conflict with previously selected packages.
+all possible versions conflict with previously selected packages
 
   previously selected package `bad v2.0.1`
     ... which satisfies dependency `bad = ">=2.0.1"` of package `baz v0.1.0`

tests/testsuite/build.rs

@@ -1264,7 +1264,9 @@ versions that meet the requirements `*` are: 0.5.0
 
 package `a-sys` links to the native library `a`, but it conflicts with a previous package which links to `a` as well:
 package `foo v0.5.0 ([ROOT]/foo)`
-Only one package in the dependency graph may specify the same links value. This helps ensure that only one copy of a native library is linked in the final binary. Try to adjust your dependencies so that only one package uses the `links = "a"` value. For more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links.
+[NOTE] only one package in the dependency graph may specify the same links value to ensure that only one copy of a native library is linked in the final binary
+for more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links
+[HELP] try to adjust your dependencies so that only one package uses the `links = "a"` value
 
 failed to select a version for `a-sys` which could resolve this conflict
 
@@ -1391,7 +1393,9 @@ versions that meet the requirements `*` are: 0.5.0
 
 package `a-sys` links to the native library `a`, but it conflicts with a previous package which links to `a` as well:
 package `foo v0.5.0 ([ROOT]/foo)`
-Only one package in the dependency graph may specify the same links value. This helps ensure that only one copy of a native library is linked in the final binary. Try to adjust your dependencies so that only one package uses the `links = "a"` value. For more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links.
+[NOTE] only one package in the dependency graph may specify the same links value to ensure that only one copy of a native library is linked in the final binary
+for more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links
+[HELP] try to adjust your dependencies so that only one package uses the `links = "a"` value
 
 failed to select a version for `a-sys` which could resolve this conflict
 
@@ -5419,7 +5423,9 @@ versions that meet the requirements `*` are: 0.5.0
 
 package `a` links to the native library `a`, but it conflicts with a previous package which links to `a` as well:
 package `foo v0.5.0 ([ROOT]/foo)`
-Only one package in the dependency graph may specify the same links value. This helps ensure that only one copy of a native library is linked in the final binary. Try to adjust your dependencies so that only one package uses the `links = "a"` value. For more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links.
+[NOTE] only one package in the dependency graph may specify the same links value to ensure that only one copy of a native library is linked in the final binary
+for more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links
+[HELP] try to adjust your dependencies so that only one package uses the `links = "a"` value
 
 failed to select a version for `a` which could resolve this conflict
 

tests/testsuite/build_script.rs

@@ -84,7 +84,7 @@ fn mixed_dependencies() {
     ... required by package `foo v0.0.1 ([ROOT]/foo)`
 versions that meet the requirements `^1.1` are: 1.1.0
 
-all possible versions conflict with previously selected packages.
+all possible versions conflict with previously selected packages
 
   previously selected package `dep v1.0.0`
     ... which satisfies dependency `dep = "^1.0"` of package `foo v0.0.1 ([ROOT]/foo)`
@@ -244,7 +244,7 @@ fn indirect_conflict() {
     ... which satisfies dependency `direct = "^1.0"` of package `foo v0.0.1 ([ROOT]/foo)`
 versions that meet the requirements `^2.1` are: 2.2.0, 2.1.0
 
-all possible versions conflict with previously selected packages.
+all possible versions conflict with previously selected packages
 
   previously selected package `indirect v2.0.0`
     ... which satisfies dependency `indirect = "^2.0"` of package `foo v0.0.1 ([ROOT]/foo)`

tests/testsuite/direct_minimal_versions.rs

@@ -196,11 +196,10 @@ fn simple_install_fail() {
 To reuse those artifacts with a future compilation, set the environment variable `CARGO_BUILD_BUILD_DIR` to that path.
 
 Caused by:
-  no matching package found
-  searched package name: `baz`
-  perhaps you meant:      bar or foo
+  no matching package named `baz` found
   location searched: directory source `[ROOT]/index` (which is replacing registry `crates-io`)
   required by package `bar v0.1.0`
+  [HELP] packages with similar names: bar or foo
 
 "#]])
         .run();
@@ -778,7 +777,7 @@ Caused by:
   candidate versions found which didn't match: 0.0.1
   location searched: directory source `[..] (which is replacing registry `[..]`)
   required by package `bar v0.1.0`
-  perhaps a crate was updated and forgotten to be re-vendored?
+  [NOTE] perhaps a crate was updated and forgotten to be re-vendored?
 
 "#]])
         .with_status(101)

tests/testsuite/directory.rs

@@ -279,7 +279,7 @@ fn dependency_activates_typoed_feature() {
 versions that meet the requirements `*` are: 0.0.1
 
 package `foo` depends on `bar` with feature `bar` but `bar` does not have that feature.
- package `bar` does have feature `baz`
+[HELP] there is a feature `baz` with a similar name
 
 
 failed to select a version for `bar` which could resolve this conflict
@@ -330,7 +330,7 @@ fn dependency_activates_feature_with_no_close_match() {
 versions that meet the requirements `*` are: 0.0.1
 
 package `foo` depends on `bar` with feature `serde` but `bar` does not have that feature.
- available features: cookies, json, tls
+[HELP] available features: cookies, json, tls
 
 
 failed to select a version for `bar` which could resolve this conflict
@@ -549,7 +549,7 @@ fn dependency_activates_required_dependency() {
 versions that meet the requirements `*` are: 0.0.1
 
 package `foo` depends on `bar` with feature `baz` but `bar` does not have that feature.
- A required dependency with that name exists, but only optional dependencies can be used as features.
+[NOTE] a required dependency with that name exists, but only optional dependencies can be used as features.
 
 
 failed to select a version for `bar` which could resolve this conflict

tests/testsuite/features.rs

@@ -891,7 +891,7 @@ dependencies = [
 candidate versions found which didn't match: 0.0.1
 location searched: `dummy-registry` index (which is replacing registry `crates-io`)
 required by package `test v0.0.0 ([ROOT]/foo)`
-perhaps a crate was updated and forgotten to be re-vendored?
+[NOTE] perhaps a crate was updated and forgotten to be re-vendored?
 
 "#]])
         .run();