Handle virtual workspaces in the tidy edition check

Author: bjorn3

src/tools/tidy/src/edition.rs

@@ -4,11 +4,6 @@ use std::path::Path;
 
 use crate::walk::{filter_dirs, walk};
 
-fn is_edition_2021(mut line: &str) -> bool {
-    line = line.trim();
-    line == "edition = \"2021\""
-}
-
 pub fn check(path: &Path, bad: &mut bool) {
     walk(path, |path, _is_dir| filter_dirs(path), &mut |entry, contents| {
         let file = entry.path();
@@ -17,8 +12,15 @@ pub fn check(path: &Path, bad: &mut bool) {
             return;
         }
 
-        let is_2021 = contents.lines().any(is_edition_2021);
-        if !is_2021 {
+        let is_2021 = contents.lines().any(|line| line.trim() == "edition = \"2021\"");
+
+        let is_workspace = contents.lines().any(|line| line.trim() == "[workspace]");
+        let is_package = contents.lines().any(|line| line.trim() == "[package]");
+        assert!(is_workspace || is_package);
+
+        // Check that all packages use the 2021 edition. Virtual workspaces don't allow setting an
+        // edition, so these shouldn't be checked.
+        if is_package && !is_2021 {
             tidy_error!(
                 bad,
                 "{} doesn't have `edition = \"2021\"` on a separate line",