Fix bug in TargetsMap that ignores non-root buck target patterns

Summary:
Add support for non-root buck target patterns that are currently shadowed by root buck target pattern matcher. Thanks Acesine for finding this bug.

~~DISCLAIMER: this is my 2nd rust diff so there's a good chance implementation is suboptimal, any/all guidance appreciated! ~~

Reviewed By: pcerl017

Differential Revision: D53147078

fbshipit-source-id: 2f67616cdc94bb5813b72046b27cc0f5c28d7082

btd/src/buck/target_map.rs

@@ -56,6 +56,11 @@ impl<T> TargetMap<T> {
                 .or_default()
                 .push(value);
         } else if let Some(prefix) = key.as_str().strip_suffix("...") {
+            // if it is foo// we need to keep the slash, if foo//bar/ we need to remove it
+            let prefix = match prefix.strip_suffix('/') {
+                Some(x) if !x.ends_with('/') => x,
+                _ => prefix,
+            };
             self.recursive_pattern
                 .update(&Package::new(prefix), move |old| {
                     let mut res = old.unwrap_or_default();
@@ -97,11 +102,12 @@ mod test {
         t.insert(&TargetLabel::new("foo//bar:quz"), 100);
         t.insert_pattern(&TargetPattern::new("foo//bar:"), 3);
         t.insert_pattern(&TargetPattern::new("foo//..."), 4);
+        t.insert_pattern(&TargetPattern::new("foo//bar/..."), 5);
         assert_eq!(
             t.get(&TargetLabel::new("foo//bar:baz"))
                 .copied()
                 .collect::<Vec<_>>(),
-            vec![1, 2, 3, 4]
+            vec![1, 2, 3, 4, 5]
         );
         assert_eq!(
             t.get(&TargetLabel::new("foo//moo:boo"))