1 files changed, 48 insertions, 0 deletions
diff --git a/third_party/rust/regex-automata/tests/dfa/regression.rs b/third_party/rust/regex-automata/tests/dfa/regression.rs
new file mode 100644
index 0000000000..09caffabcb
--- /dev/null
+++ b/third_party/rust/regex-automata/tests/dfa/regression.rs
@@ -0,0 +1,48 @@
+// A regression test for checking that minimization correctly translates
+// whether a state is a match state or not. Previously, it was possible for
+// minimization to mark a non-matching state as matching.
+#[test]
+#[cfg(not(miri))]
+fn minimize_sets_correct_match_states() {
+    use regex_automata::{
+        dfa::{dense::DFA, Automaton, StartKind},
+        Anchored, Input,
+    };
+
+    let pattern =
+        // This is a subset of the grapheme matching regex. I couldn't seem
+        // to get a repro any smaller than this unfortunately.
+        r"(?x)
+            (?:
+                \p{gcb=Prepend}*
+                (?:
+                    (?:
+                        (?:
+                            \p{gcb=L}*
+                            (?:\p{gcb=V}+|\p{gcb=LV}\p{gcb=V}*|\p{gcb=LVT})
+                            \p{gcb=T}*
+                        )
+                        |
+                        \p{gcb=L}+
+                        |
+                        \p{gcb=T}+
+                    )
+                    |
+                    \p{Extended_Pictographic}
+                    (?:\p{gcb=Extend}*\p{gcb=ZWJ}\p{Extended_Pictographic})*
+                    |
+                    [^\p{gcb=Control}\p{gcb=CR}\p{gcb=LF}]
+                )
+                [\p{gcb=Extend}\p{gcb=ZWJ}\p{gcb=SpacingMark}]*
+            )
+        ";
+
+    let dfa = DFA::builder()
+        .configure(
+            DFA::config().start_kind(StartKind::Anchored).minimize(true),
+        )
+        .build(pattern)
+        .unwrap();
+    let input = Input::new(b"\xE2").anchored(Anchored::Yes);
+    assert_eq!(Ok(None), dfa.try_search_fwd(&input));
+}