Auto merge of #8773 - pickfire:patch-1, r=ehuss

Add actionable help message for --features

Fix #8770

Author: bors

crates/cargo-test-support/src/lib.rs

@@ -1521,6 +1521,7 @@ fn substitute_macros(input: &str) -> String {
         ("[ERROR]", "error:"),
         ("[WARNING]", "warning:"),
         ("[NOTE]", "note:"),
+        ("[HELP]", "help:"),
         ("[DOCUMENTING]", " Documenting"),
         ("[FRESH]", "       Fresh"),
         ("[UPDATING]", "    Updating"),

src/cargo/util/command_prelude.rs

@@ -308,7 +308,8 @@ pub trait ArgMatchesExt {
                 if self._is_present(flag) {
                     bail!(
                         "--{} is not allowed in the root of a virtual workspace\n\
-                         note: while this was previously accepted, it didn't actually do anything",
+                         note: while this was previously accepted, it didn't actually do anything\n\
+                         help: change the current directory to the package directory, or use the --manifest-path flag to the path of the package",
                         flag
                     );
                 }

tests/testsuite/features.rs

@@ -1939,15 +1939,17 @@ fn virtual_ws_flags() {
     p.cargo("build --features=f1")
         .with_stderr(
             "[ERROR] --features is not allowed in the root of a virtual workspace\n\
-             note: while this was previously accepted, it didn't actually do anything",
+             [NOTE] while this was previously accepted, it didn't actually do anything\n\
+             [HELP] change the current directory to the package directory, or use the --manifest-path flag to the path of the package",
         )
         .with_status(101)
         .run();
 
     p.cargo("build --no-default-features")
         .with_stderr(
             "[ERROR] --no-default-features is not allowed in the root of a virtual workspace\n\
-             note: while this was previously accepted, it didn't actually do anything",
+             [NOTE] while this was previously accepted, it didn't actually do anything\n\
+             [HELP] change the current directory to the package directory, or use the --manifest-path flag to the path of the package",
         )
         .with_status(101)
         .run();

tests/testsuite/package_features.rs

@@ -57,6 +57,7 @@ fn virtual_no_default_features() {
             "\
 [ERROR] --no-default-features is not allowed in the root of a virtual workspace
 [NOTE] while this was previously accepted, it didn't actually do anything
+[HELP] change the current directory to the package directory, or use the --manifest-path flag to the path of the package
 ",
         )
         .run();
@@ -125,6 +126,7 @@ fn virtual_features() {
             "\
 [ERROR] --features is not allowed in the root of a virtual workspace
 [NOTE] while this was previously accepted, it didn't actually do anything
+[HELP] change the current directory to the package directory, or use the --manifest-path flag to the path of the package
 ",
         )
         .run();
@@ -202,6 +204,7 @@ fn virtual_with_specific() {
             "\
 [ERROR] --features is not allowed in the root of a virtual workspace
 [NOTE] while this was previously accepted, it didn't actually do anything
+[HELP] change the current directory to the package directory, or use the --manifest-path flag to the path of the package
 ",
         )
         .run();
@@ -371,6 +374,7 @@ fn virtual_member_slash() {
             "\
 [ERROR] --features is not allowed in the root of a virtual workspace
 [NOTE] while this was previously accepted, it didn't actually do anything
+[HELP] change the current directory to the package directory, or use the --manifest-path flag to the path of the package
 ",
         )
         .run();