improve error message and add related tests

Author: domsleee

src/cargo/ops/common_for_install_and_uninstall.rs

@@ -616,9 +616,9 @@ where
         let examples = candidates
             .iter()
             .filter(|cand| cand.targets().iter().filter(|t| t.is_example()).count() > 0);
-        let pkg = match one(binaries, |v| multi_err("binaries", v))? {
+        let pkg = match one(binaries, |v| multi_err("binaries", source, v))? {
             Some(p) => p,
-            None => match one(examples, |v| multi_err("examples", v))? {
+            None => match one(examples, |v| multi_err("examples", source, v))? {
                 Some(p) => p,
                 None => bail!(
                     "no packages found with binaries or \
@@ -629,17 +629,23 @@ where
         Ok(pkg.clone())
     };
 
-    fn multi_err(kind: &str, mut pkgs: Vec<&Package>) -> String {
+    fn multi_err<T>(kind: &str, source: &T, mut pkgs: Vec<&Package>) -> String
+    where
+    T: Source
+    {
         pkgs.sort_unstable_by_key(|a| a.name());
+        let first_pkg = pkgs.iter().nth(0).unwrap();
         format!(
             "multiple packages with {} found: {}. When installing a git repository, \
-            cargo will always search the entire repo for any Cargo.toml. \
-            Please specify which to install.",
+            cargo will always search the entire repo for any Cargo.toml.\n\
+            Please specify a package, e.g. `cargo install --git {} {}`.",
             kind,
             pkgs.iter()
                 .map(|p| p.name().as_str())
                 .collect::<Vec<_>>()
-                .join(", ")
+                .join(", "),
+            source.source_id().url().as_str(),
+            first_pkg.name()
         )
     }
 }

tests/testsuite/install.rs

@@ -4,7 +4,7 @@ use std::fs::{self, OpenOptions};
 use std::io::prelude::*;
 use std::path::Path;
 
-use cargo_test_support::compare;
+use cargo_test_support::{compare};
 use cargo_test_support::cross_compile;
 use cargo_test_support::git;
 use cargo_test_support::registry::{self, registry_path, Package};
@@ -560,28 +560,107 @@ Available binaries:
 }
 
 #[cargo_test]
-fn multiple_crates_error() {
+fn multiple_binaries_error() {
     let p = git::repo(&paths::root().join("foo"))
         .file("Cargo.toml", &basic_manifest("foo", "0.1.0"))
         .file("src/main.rs", "fn main() {}")
         .file("a/Cargo.toml", &basic_manifest("bar", "0.1.0"))
         .file("a/src/main.rs", "fn main() {}")
         .build();
 
+    let git_url = p.url().to_string();
     cargo_process("install --git")
         .arg(p.url().to_string())
         .with_status(101)
         .with_stderr(
-            "\
+            format!("\
 [UPDATING] git repository [..]
 [ERROR] multiple packages with binaries found: bar, foo. \
-When installing a git repository, cargo will always search the entire repo for any Cargo.toml. \
-Please specify which to install.
-",
+When installing a git repository, cargo will always search the entire repo for any Cargo.toml.\n\
+Please specify a package, e.g. `cargo install --git {git_url} bar`.
+"),
         )
         .run();
 }
 
+#[cargo_test]
+fn multiple_examples_error() {
+    let p = git::repo(&paths::root().join("foo"))
+        .file("Cargo.toml", &basic_manifest("foo", "0.1.0"))
+        .file("src/lib.rs", "")
+        .file("examples/ex1.rs", "fn main() {}")
+        .file("bar/Cargo.toml", &basic_manifest("bar", "0.1.0"))
+        .file("bar/src/lib.rs", "")
+        .file("bar/examples/ex1.rs", "fn main() {}",)
+        .build();
+    
+    let git_url = p.url().to_string();
+    cargo_process("install --example ex1 --git")
+        .arg(p.url().to_string())
+        .with_status(101)
+        .with_stderr(format!("\
+[UPDATING] git repository [..]
+[ERROR] multiple packages with examples found: bar, foo. \
+When installing a git repository, cargo will always search the entire repo for any Cargo.toml.\n\
+Please specify a package, e.g. `cargo install --git {git_url} bar`."))
+        .run();
+}
+
+#[cargo_test]
+fn multiple_binaries_deep_select_uses_package_name() {
+    let p = git::repo(&paths::root().join("foo"))
+        .file("Cargo.toml", &basic_manifest("foo", "0.1.0"))
+        .file("src/main.rs", "fn main() {}")
+        .file("bar/baz/Cargo.toml", &basic_manifest("baz", "0.1.0"))
+        .file("bar/baz/src/main.rs", "fn main() {}")
+        .build();
+
+    cargo_process("install --git")
+        .arg(p.url().to_string())
+        .arg("baz")
+        .run();
+}
+
+#[cargo_test]
+fn multiple_binaries_in_selected_package_installs_all() {
+    let p = git::repo(&paths::root().join("foo"))
+        .file("Cargo.toml", &basic_manifest("foo", "0.1.0"))
+        .file("src/lib.rs", "")
+        .file("bar/Cargo.toml", &basic_manifest("bar", "0.1.0"))
+        .file("bar/src/bin/bin1.rs", "fn main() {}")
+        .file("bar/src/bin/bin2.rs", "fn main() {}")
+        .build();
+
+    cargo_process("install --git")
+        .arg(p.url().to_string())
+        .arg("bar")
+        .run();
+
+    let cargo_home = cargo_home();
+    assert_has_installed_exe(&cargo_home, "bin1");
+    assert_has_installed_exe(&cargo_home, "bin2");
+}
+
+#[cargo_test]
+fn multiple_binaries_in_selected_package_with_bin_option_installs_only_one() {
+    let p = git::repo(&paths::root().join("foo"))
+        .file("Cargo.toml", &basic_manifest("foo", "0.1.0"))
+        .file("src/lib.rs", "")
+        .file("bar/Cargo.toml", &basic_manifest("bar", "0.1.0"))
+        .file("bar/src/bin/bin1.rs", "fn main() {}")
+        .file("bar/src/bin/bin2.rs", "fn main() {}")
+        .build();
+
+    cargo_process("install --bin bin1 --git")
+        .arg(p.url().to_string())
+        .arg("bar")
+        .run();
+
+    let cargo_home = cargo_home();
+    assert_has_installed_exe(&cargo_home, "bin1");
+    assert_has_not_installed_exe(&cargo_home, "bin2");
+}
+
 #[cargo_test]
 fn multiple_crates_select() {
     let p = git::repo(&paths::root().join("foo"))
@@ -689,6 +768,7 @@ fn multiple_crates_auto_examples() {
     assert_has_installed_exe(cargo_home(), "foo");
 }
 
+
 #[cargo_test]
 fn no_binaries_or_examples() {
     let p = project()