Auto merge of #6188 - ebroto:primary_package, r=flip1995

Add --no-deps option to avoid running on path dependencies in workspaces

Since rust-lang/cargo#8758 has hit nightly, this allows us to address the second bullet point and [the concern related to `--fix`](https://github.com/rust-lang/cargo/issues/8143#issuecomment-619289546) in the [RUSTC_WORKSPACE_WRAPPER tracking issue](https://github.com/rust-lang/cargo/issues/8143).

As a reminder stabilizing that env var will solve #4612 (Clippy not running after `cargo check` in stable) and would allow to stabilize the `--fix` option in Clippy.

changelog: Add `--no-deps` option to avoid running on path dependencies in workspaces

Fixes #3025

2 files changed, 58 insertions, 18 deletions

diff --git a/src/driver.rs b/src/driver.rs
index ef31c72481a..e490ee54c0b 100644
--- a/src/driver.rs
+++ b/src/driver.rs
@@ -182,6 +182,7 @@ fn toolchain_path(home: Option<String>, toolchain: Option<String>) -> Option<Pat
     })
 }
 
+#[allow(clippy::too_many_lines)]
 pub fn main() {
     rustc_driver::init_rustc_env_logger();
     SyncLazy::force(&ICE_HOOK);
@@ -277,27 +278,40 @@ pub fn main() {
             args.extend(vec!["--sysroot".into(), sys_root]);
         };
 
-        // this check ensures that dependencies are built but not linted and the final
-        // crate is linted but not built
-        let clippy_enabled = env::var("CLIPPY_TESTS").map_or(false, |val| val == "true")
-            || arg_value(&orig_args, "--cap-lints", |val| val == "allow").is_none();
-
+        let mut no_deps = false;
+        let clippy_args = env::var("CLIPPY_ARGS")
+            .unwrap_or_default()
+            .split("__CLIPPY_HACKERY__")
+            .filter_map(|s| match s {
+                "" => None,
+                "--no-deps" => {
+                    no_deps = true;
+                    None
+                },
+                _ => Some(s.to_string()),
+            })
+            .chain(vec!["--cfg".into(), r#"feature="cargo-clippy""#.into()])
+            .collect::<Vec<String>>();
+
+        // We enable Clippy if one of the following conditions is met
+        // - IF Clippy is run on its test suite OR
+        // - IF Clippy is run on the main crate, not on deps (`!cap_lints_allow`) THEN
+        //    - IF `--no-deps` is not set (`!no_deps`) OR
+        //    - IF `--no-deps` is set and Clippy is run on the specified primary package
+        let clippy_tests_set = env::var("CLIPPY_TESTS").map_or(false, |val| val == "true");
+        let cap_lints_allow = arg_value(&orig_args, "--cap-lints", |val| val == "allow").is_some();
+        let in_primary_package = env::var("CARGO_PRIMARY_PACKAGE").is_ok();
+
+        let clippy_enabled = clippy_tests_set || (!cap_lints_allow && (!no_deps || in_primary_package));
         if clippy_enabled {
-            args.extend(vec!["--cfg".into(), r#"feature="cargo-clippy""#.into()]);
-            if let Ok(extra_args) = env::var("CLIPPY_ARGS") {
-                args.extend(extra_args.split("__CLIPPY_HACKERY__").filter_map(|s| {
-                    if s.is_empty() {
-                        None
-                    } else {
-                        Some(s.to_string())
-                    }
-                }));
-            }
+            args.extend(clippy_args);
         }
+
         let mut clippy = ClippyCallbacks;
         let mut default = DefaultCallbacks;
         let callbacks: &mut (dyn rustc_driver::Callbacks + Send) =
             if clippy_enabled { &mut clippy } else { &mut default };
+
         rustc_driver::RunCompiler::new(&args, callbacks).run()
     }))
 }
diff --git a/src/main.rs b/src/main.rs
index 6739a4cf224..ea06743394d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -62,7 +62,7 @@ struct ClippyCmd {
     unstable_options: bool,
     cargo_subcommand: &'static str,
     args: Vec<String>,
-    clippy_args: String,
+    clippy_args: Vec<String>,
 }
 
 impl ClippyCmd {
@@ -99,7 +99,10 @@ impl ClippyCmd {
             args.insert(0, "+nightly".to_string());
         }
 
-        let clippy_args: String = old_args.map(|arg| format!("{}__CLIPPY_HACKERY__", arg)).collect();
+        let mut clippy_args: Vec<String> = old_args.collect();
+        if cargo_subcommand == "fix" && !clippy_args.iter().any(|arg| arg == "--no-deps") {
+            clippy_args.push("--no-deps".into());
+        }
 
         ClippyCmd {
             unstable_options,
@@ -147,10 +150,15 @@ impl ClippyCmd {
 
     fn into_std_cmd(self) -> Command {
         let mut cmd = Command::new("cargo");
+        let clippy_args: String = self
+            .clippy_args
+            .iter()
+            .map(|arg| format!("{}__CLIPPY_HACKERY__", arg))
+            .collect();
 
         cmd.env(self.path_env(), Self::path())
             .envs(ClippyCmd::target_dir())
-            .env("CLIPPY_ARGS", self.clippy_args)
+            .env("CLIPPY_ARGS", clippy_args)
             .arg(self.cargo_subcommand)
             .args(&self.args);
 
@@ -202,6 +210,24 @@ mod tests {
     }
 
     #[test]
+    fn fix_implies_no_deps() {
+        let args = "cargo clippy --fix -Zunstable-options"
+            .split_whitespace()
+            .map(ToString::to_string);
+        let cmd = ClippyCmd::new(args);
+        assert!(cmd.clippy_args.iter().any(|arg| arg == "--no-deps"));
+    }
+
+    #[test]
+    fn no_deps_not_duplicated_with_fix() {
+        let args = "cargo clippy --fix -Zunstable-options -- --no-deps"
+            .split_whitespace()
+            .map(ToString::to_string);
+        let cmd = ClippyCmd::new(args);
+        assert_eq!(cmd.clippy_args.iter().filter(|arg| *arg == "--no-deps").count(), 1);
+    }
+
+    #[test]
     fn check() {
         let args = "cargo clippy".split_whitespace().map(ToString::to_string);
         let cmd = ClippyCmd::new(args);