fix: Avoid warning config twice

Author: linyihai

src/cargo/util/context/mod.rs

@@ -1590,10 +1590,14 @@ impl GlobalContext {
             }
         }
 
+        // Need to check the `$CARGO_HOME/config` have been warned already.
+        let home_config_without_extention = home.join("config");
+        let already_warned = stash.contains(&home_config_without_extention);
+
         // Once we're done, also be sure to walk the home directory even if it's not
         // in our history to be sure we pick up that standard location for
         // information.
-        if let Some(path) = self.get_file_path(home, "config", true)? {
+        if let Some(path) = self.get_file_path(home, "config", !already_warned)? {
             if !stash.contains(&path) {
                 walk(&path)?;
             }

tests/testsuite/config.rs

@@ -315,8 +315,6 @@ f1 = 1
         .with_stderr_data(str![[r#"
 [WARNING] `[ROOT]/.cargo/config` is deprecated in favor of `config.toml`
 [NOTE] if you need to support cargo 1.38 or earlier, you can symlink `config` to `config.toml`
-[WARNING] `[ROOT]/.cargo/config` is deprecated in favor of `config.toml`
-[NOTE] if you need to support cargo 1.38 or earlier, you can symlink `config` to `config.toml`
 
 "#]])
         .run();