multiple configs: add tests

clippy_lints/src/utils/conf.rs

@@ -333,10 +333,10 @@ pub fn lookup_conf_file() -> io::Result<Option<PathBuf>> {
                     Err(e) => return Err(e),
                     Ok(md) if md.is_dir() => {},
                     Ok(_) => {
-                        // warn if we happen to find two config files
+                        // warn if we happen to find two config files #8323
                         if let Some(ref found_config_) = found_config {
                             eprintln!(
-                                "Warning: found two config files: {} and {}.\nUsing the first one!",
+                                "Using config file `{}`\nWarning: `{}` will be ignored.",
                                 found_config_.display(),
                                 config_file.display(),
                             );

tests/ui-cargo/multiple_config_files/no_warn/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "no_warn"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

tests/ui-cargo/multiple_config_files/no_warn/clippy.toml

@@ -0,0 +1 @@
+avoid-breaking-exported-api = false

tests/ui-cargo/multiple_config_files/no_warn/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

tests/ui-cargo/multiple_config_files/warn/.clippy.toml

@@ -0,0 +1 @@
+avoid-breaking-exported-api = false

tests/ui-cargo/multiple_config_files/warn/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "warn"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

tests/ui-cargo/multiple_config_files/warn/clippy.toml

@@ -0,0 +1 @@
+avoid-breaking-exported-api = false

tests/ui-cargo/multiple_config_files/warn/src/main.rs

@@ -0,0 +1,3 @@
+fn main() {
+    println!("Hello, world!");
+}

tests/ui-cargo/multiple_config_files/warn/src/main.stderr

@@ -0,0 +1,2 @@
+Using config file `$SRC_DIR/tests/ui-cargo/multiple_config_files/warn/.clippy.toml`
+Warning: `$SRC_DIR/tests/ui-cargo/multiple_config_files/warn/clippy.toml` will be ignored.