From 6cabd9e67f537cd6dec78663742b69f249ed63d0 Mon Sep 17 00:00:00 2001
From: Riley Bruins <ribru17@hotmail.com>
Date: Tue, 3 Jun 2025 18:41:12 +0200
Subject: [PATCH] fix(query)!: assert that predicates end in `!` or `?`

Predicates/directives are documented to end in either `!` or `?`.
However, `query.c` allows them to be any valid identifier, and also
allows `?` or `!` characters anywhere inside an identifier.

This commit removes `?` and `!` from the list of valid identifier
characters, and asserts that predicates/directives only *end* in `?` or
`!`, respectively.

This commit is breaking because you can no longer do something like
`(#eq? @capture foo!bar)` (`foo!bar` must now be quoted).
---
 cli/src/tests/query_test.rs | 18 +++++++++++++++---
 lib/src/query.c             |  8 +++++---
 2 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/cli/src/tests/query_test.rs b/cli/src/tests/query_test.rs
index ec77c91c..5486a537 100644
--- a/cli/src/tests/query_test.rs
+++ b/cli/src/tests/query_test.rs
@@ -117,12 +117,24 @@ fn test_query_errors_on_invalid_syntax() {
 
         // Unclosed sibling expression with predicate
         assert_eq!(
-            Query::new(&language, r"((identifier) (#a)")
+            Query::new(&language, r"((identifier) (#a?)")
                 .unwrap_err()
                 .message,
             [
-                "((identifier) (#a)", //
-                "                  ^",
+                "((identifier) (#a?)", //
+                "                   ^",
+            ]
+            .join("\n")
+        );
+
+        // Predicate not ending in `?` or `!`
+        assert_eq!(
+            Query::new(&language, r"((identifier) (#a))")
+                .unwrap_err()
+                .message,
+            [
+                "((identifier) (#a))", //
+                "                 ^",
             ]
             .join("\n")
         );
diff --git a/lib/src/query.c b/lib/src/query.c
index 4748a00f..73c1e936 100644
--- a/lib/src/query.c
+++ b/lib/src/query.c
@@ -411,9 +411,7 @@ static void stream_scan_identifier(Stream *stream) {
     iswalnum(stream->next) ||
     stream->next == '_' ||
     stream->next == '-' ||
-    stream->next == '.' ||
-    stream->next == '?' ||
-    stream->next == '!'
+    stream->next == '.'
   );
 }
 
@@ -2092,6 +2090,10 @@ static TSQueryError ts_query__parse_predicate(
   if (!stream_is_ident_start(stream)) return TSQueryErrorSyntax;
   const char *predicate_name = stream->input;
   stream_scan_identifier(stream);
+  if (stream->next != '?' && stream->next != '!') {
+    return TSQueryErrorSyntax;
+  }
+  stream_advance(stream);
   uint32_t length = (uint32_t)(stream->input - predicate_name);
   uint16_t id = symbol_table_insert_name(
     &self->predicate_values,