From a4f89eab03e49512f62272cd03b91b38da6110d7 Mon Sep 17 00:00:00 2001
From: hi-rustin <rustin.liu@gmail.com>
Date: Tue, 15 Nov 2022 09:41:39 +0800
Subject: [PATCH 1/2] Add warning when `cargo tree -i <spec>` can not find
 packages

Signed-off-by: hi-rustin <rustin.liu@gmail.com>
---
 src/cargo/ops/tree/mod.rs |  8 +++++-
 tests/testsuite/tree.rs   | 56 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/src/cargo/ops/tree/mod.rs b/src/cargo/ops/tree/mod.rs
index 134670cf988..5097f3e46e7 100644
--- a/src/cargo/ops/tree/mod.rs
+++ b/src/cargo/ops/tree/mod.rs
@@ -213,7 +213,13 @@ pub fn build_and_print(ws: &Workspace<'_>, opts: &TreeOptions) -> CargoResult<()
         })
         .collect::<CargoResult<Vec<PackageIdSpec>>>()?;
 
-    print(ws.config(), opts, root_indexes, &pkgs_to_prune, &graph)?;
+    if root_indexes.len() == 0 {
+        ws.config().shell().warn("nothing to print.\n\n\
+        To find dependencies that require specific features or target platforms, \
+        try use options `--all-features` or `--target all` first, and then narrow your search scope accordingly.")?;
+    } else {
+        print(ws.config(), opts, root_indexes, &pkgs_to_prune, &graph)?;
+    }
     Ok(())
 }
 
diff --git a/tests/testsuite/tree.rs b/tests/testsuite/tree.rs
index d053c473176..d6002db905c 100644
--- a/tests/testsuite/tree.rs
+++ b/tests/testsuite/tree.rs
@@ -489,6 +489,62 @@ foo v0.1.0 ([..]/foo)
         .run();
 }
 
+#[cargo_test]
+fn no_selected_target_dependency() {
+    // --target flag
+    if cross_compile::disabled() {
+        return;
+    }
+    Package::new("targetdep", "1.0.0").publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            &format!(
+                r#"
+                [package]
+                name = "foo"
+                version = "0.1.0"
+
+                [target.'{alt}'.dependencies]
+                targetdep = "1.0"
+
+                "#,
+                alt = alternate(),
+            ),
+        )
+        .file("src/lib.rs", "")
+        .file("build.rs", "fn main() {}")
+        .build();
+
+    p.cargo("tree")
+        .with_stdout(
+            "\
+foo v0.1.0 ([..]/foo)
+",
+        )
+        .run();
+
+    p.cargo("tree -i targetdep")
+        .with_stderr(
+            "\
+[WARNING] nothing to print.
+
+To find dependencies that require specific features or target platforms, \
+try use options `--all-features` or `--target all` first, and then narrow your search scope accordingly.
+",
+        )
+        .run();
+    p.cargo("tree -i targetdep --target all")
+        .with_stdout(
+            "\
+targetdep v1.0.0
+└── foo v0.1.0 ([..]/foo)
+",
+        )
+        .run();
+}
+
 #[cargo_test]
 fn dep_kinds() {
     Package::new("inner-devdep", "1.0.0").publish();

From c5eb61823cf22bc5735b93e3e0717e44a0bede17 Mon Sep 17 00:00:00 2001
From: hi-rustin <rustin.liu@gmail.com>
Date: Thu, 17 Nov 2022 08:59:08 +0800
Subject: [PATCH 2/2] Remove the `--all-features` tip

Signed-off-by: hi-rustin <rustin.liu@gmail.com>
---
 src/cargo/ops/tree/mod.rs | 8 +++++---
 tests/testsuite/tree.rs   | 4 ++--
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/cargo/ops/tree/mod.rs b/src/cargo/ops/tree/mod.rs
index 5097f3e46e7..14c5509b313 100644
--- a/src/cargo/ops/tree/mod.rs
+++ b/src/cargo/ops/tree/mod.rs
@@ -214,9 +214,11 @@ pub fn build_and_print(ws: &Workspace<'_>, opts: &TreeOptions) -> CargoResult<()
         .collect::<CargoResult<Vec<PackageIdSpec>>>()?;
 
     if root_indexes.len() == 0 {
-        ws.config().shell().warn("nothing to print.\n\n\
-        To find dependencies that require specific features or target platforms, \
-        try use options `--all-features` or `--target all` first, and then narrow your search scope accordingly.")?;
+        ws.config().shell().warn(
+            "nothing to print.\n\n\
+        To find dependencies that require specific target platforms, \
+        try use option `--target all` first, and then narrow your search scope accordingly.",
+        )?;
     } else {
         print(ws.config(), opts, root_indexes, &pkgs_to_prune, &graph)?;
     }
diff --git a/tests/testsuite/tree.rs b/tests/testsuite/tree.rs
index d6002db905c..4d3aee4fcb9 100644
--- a/tests/testsuite/tree.rs
+++ b/tests/testsuite/tree.rs
@@ -530,8 +530,8 @@ foo v0.1.0 ([..]/foo)
             "\
 [WARNING] nothing to print.
 
-To find dependencies that require specific features or target platforms, \
-try use options `--all-features` or `--target all` first, and then narrow your search scope accordingly.
+To find dependencies that require specific target platforms, \
+try use option `--target all` first, and then narrow your search scope accordingly.
 ",
         )
         .run();