Auto merge of #121992 - jieyouxu:fix-tidy-unpaired-revision, r=onur-ozkan

tidy: split dots in filename not the entire path when checking for stray stdout/stderr files

I committed a path crime by splitting the entire path on `.`, when I meant to split on the filename. This means that any parent folders which contain `.` will cause tidy failure. Added a regression test so that doesn't happen again.

### Follow-up

- [ ] Adjust rustc-dev-guide to document assert on test name not containing dots. https://github.com/rust-lang/rustc-dev-guide/pull/1927

Fixes #121986.

1 files changed, 19 insertions, 7 deletions

diff --git a/src/tools/tidy/src/tests_revision_unpaired_stdout_stderr.rs b/src/tools/tidy/src/tests_revision_unpaired_stdout_stderr.rs
index 394f95e9144..a0773c85bef 100644
--- a/src/tools/tidy/src/tests_revision_unpaired_stdout_stderr.rs
+++ b/src/tools/tidy/src/tests_revision_unpaired_stdout_stderr.rs
@@ -84,10 +84,16 @@ pub fn check(tests_path: impl AsRef<Path>, bad: &mut bool) {
                 }
             });
 
-            let Some((test_name, _)) = test.to_str().map(|s| s.split_once('.')).flatten() else {
+            let Some(test_name) = test.file_stem().map(OsStr::to_str).flatten() else {
                 continue;
             };
 
+            assert!(
+                !test_name.contains('.'),
+                "test name cannot contain dots '.': `{}`",
+                test.display()
+            );
+
             test_info.insert(test_name.to_string(), (test, expected_revisions));
         }
 
@@ -98,14 +104,20 @@ pub fn check(tests_path: impl AsRef<Path>, bad: &mut bool) {
         for sibling in files_under_inspection.iter().filter(|f| {
             f.extension().map(OsStr::to_str).flatten().is_some_and(|ext| EXTENSIONS.contains(&ext))
         }) {
-            let filename_components = sibling.to_str().unwrap().split('.').collect::<Vec<_>>();
-            let file_prefix = filename_components[0];
+            let Some(filename) = sibling.file_name().map(OsStr::to_str).flatten() else {
+                continue;
+            };
+
+            let filename_components = filename.split('.').collect::<Vec<_>>();
+            let [file_prefix, ..] = &filename_components[..] else {
+                continue;
+            };
 
-            let Some((test_path, expected_revisions)) = test_info.get(file_prefix) else {
+            let Some((test_path, expected_revisions)) = test_info.get(*file_prefix) else {
                 continue;
             };
 
-            match filename_components[..] {
+            match &filename_components[..] {
                 // Cannot have a revision component, skip.
                 [] | [_] => return,
                 [_, _] if !expected_revisions.is_empty() => {
@@ -120,9 +132,9 @@ pub fn check(tests_path: impl AsRef<Path>, bad: &mut bool) {
                 [_, _] => return,
                 [_, found_revision, .., extension] => {
                     if !IGNORES.contains(&found_revision)
-                        && !expected_revisions.contains(found_revision)
+                        && !expected_revisions.contains(*found_revision)
                         // This is from `//@ stderr-per-bitwidth`
-                        && !(extension == "stderr" && ["32bit", "64bit"].contains(&found_revision))
+                        && !(*extension == "stderr" && ["32bit", "64bit"].contains(&found_revision))
                     {
                         // Found some unexpected revision-esque component that is not a known
                         // compare-mode or expected revision.