Auto merge of #10999 - hi-rustin:rustin-patch-wrong-names, r=epage

Improve error message for wrong target names

### What does this PR try to resolve?

Fixes #10982

We can print all available targets for users.

### How should we test and review this PR?

- [x] unit test

Author: bors

src/cargo/ops/cargo_compile.rs

@@ -23,6 +23,7 @@
 //!       repeats until the queue is empty.
 
 use std::collections::{BTreeSet, HashMap, HashSet};
+use std::fmt::Write;
 use std::hash::{Hash, Hasher};
 use std::sync::Arc;
 
@@ -1526,19 +1527,40 @@ fn find_named_targets<'a>(
     };
 
     if proposals.is_empty() {
-        let targets = packages.iter().flat_map(|pkg| {
-            pkg.targets()
-                .iter()
-                .filter(|target| is_expected_kind(target))
-        });
-        let suggestion = closest_msg(target_name, targets, |t| t.name());
-        anyhow::bail!(
-            "no {} target {} `{}`{}",
-            target_desc,
-            if is_glob { "matches pattern" } else { "named" },
-            target_name,
-            suggestion
-        );
+        let targets = packages
+            .iter()
+            .flat_map(|pkg| {
+                pkg.targets()
+                    .iter()
+                    .filter(|target| is_expected_kind(target))
+            })
+            .collect::<Vec<_>>();
+        let suggestion = closest_msg(target_name, targets.iter(), |t| t.name());
+        if !suggestion.is_empty() {
+            anyhow::bail!(
+                "no {} target {} `{}`{}",
+                target_desc,
+                if is_glob { "matches pattern" } else { "named" },
+                target_name,
+                suggestion
+            );
+        } else {
+            let mut msg = String::new();
+            writeln!(
+                msg,
+                "no {} target {} `{}`.",
+                target_desc,
+                if is_glob { "matches pattern" } else { "named" },
+                target_name,
+            )?;
+            if !targets.is_empty() {
+                writeln!(msg, "Available {} targets:", target_desc)?;
+                for target in targets {
+                    writeln!(msg, "    {}", target.name())?;
+                }
+            }
+            anyhow::bail!(msg);
+        }
     }
     Ok(proposals)
 }

tests/testsuite/build.rs

@@ -1041,7 +1041,14 @@ fn cargo_compile_with_filename() {
 
     p.cargo("build --bin bin.rs")
         .with_status(101)
-        .with_stderr("[ERROR] no bin target named `bin.rs`")
+        .with_stderr(
+            "\
+[ERROR] no bin target named `bin.rs`.
+Available bin targets:
+    a
+
+",
+        )
         .run();
 
     p.cargo("build --bin a.rs")
@@ -1056,7 +1063,14 @@ fn cargo_compile_with_filename() {
 
     p.cargo("build --example example.rs")
         .with_status(101)
-        .with_stderr("[ERROR] no example target named `example.rs`")
+        .with_stderr(
+            "\
+[ERROR] no example target named `example.rs`.
+Available example targets:
+    a
+
+",
+        )
         .run();
 
     p.cargo("build --example a.rs")

tests/testsuite/run.rs

@@ -503,7 +503,10 @@ automatically infer them to be a target, such as in subfolders.
 
 For more information on this warning you can consult
 https://github.com/rust-lang/cargo/issues/5330
-error: no example target named `a`
+error: no example target named `a`.
+Available example targets:
+    do_magic
+
 ",
         )
         .run();
@@ -528,7 +531,14 @@ fn run_example_autodiscover_2015_with_autoexamples_disabled() {
     let p = autodiscover_examples_project("2015", Some(false));
     p.cargo("run --example a")
         .with_status(101)
-        .with_stderr("error: no example target named `a`\n")
+        .with_stderr(
+            "\
+error: no example target named `a`.
+Available example targets:
+    do_magic
+
+",
+        )
         .run();
 }
 
@@ -600,7 +610,14 @@ fn run_with_filename() {
 
     p.cargo("run --bin bin.rs")
         .with_status(101)
-        .with_stderr("[ERROR] no bin target named `bin.rs`")
+        .with_stderr(
+            "\
+[ERROR] no bin target named `bin.rs`.
+Available bin targets:
+    a
+
+",
+        )
         .run();
 
     p.cargo("run --bin a.rs")
@@ -615,7 +632,14 @@ fn run_with_filename() {
 
     p.cargo("run --example example.rs")
         .with_status(101)
-        .with_stderr("[ERROR] no example target named `example.rs`")
+        .with_stderr(
+            "\
+[ERROR] no example target named `example.rs`.
+Available example targets:
+    a
+
+",
+        )
         .run();
 
     p.cargo("run --example a.rs")

tests/testsuite/test.rs

@@ -2122,11 +2122,21 @@ fn bad_example() {
 
     p.cargo("run --example foo")
         .with_status(101)
-        .with_stderr("[ERROR] no example target named `foo`")
+        .with_stderr(
+            "\
+[ERROR] no example target named `foo`.
+
+",
+        )
         .run();
     p.cargo("run --bin foo")
         .with_status(101)
-        .with_stderr("[ERROR] no bin target named `foo`")
+        .with_stderr(
+            "\
+[ERROR] no bin target named `foo`.
+
+",
+        )
         .run();
 }