From 159004c2e4731b15fa5381ac2ec776082060f628 Mon Sep 17 00:00:00 2001
From: Laria Carolin Chabowski <laria@laria.me>
Date: Sat, 1 Jul 2023 16:59:23 +0200
Subject: [PATCH] Parser: Fix destroying invalid data in nested pairs

---
 src/parser.c      | 29 +++++++++++++++++++++++------
 src/parser_test.c |  7 +++++++
 2 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/src/parser.c b/src/parser.c
index 6d3498c..11e1f45 100644
--- a/src/parser.c
+++ b/src/parser.c
@@ -2108,13 +2108,30 @@ error:
     return false;
 }
 
+static struct fragment
+empty_fragment(void)
+{
+    return (struct fragment) { // Something we can safely deinit
+        .type = FRAG_BLANK,
+    };
+}
+
+static struct fragment *
+new_empty_fragment(struct apfl_allocator allocator)
+{
+    struct fragment *fragment = ALLOC_OBJ(allocator, struct fragment);
+    if (fragment == NULL) {
+        return NULL;
+    }
+
+    *fragment = empty_fragment();
+    return fragment;
+}
+
 static enum parse_fragment_result
 parse_fragment(apfl_parser_ptr p, struct fragment *fragment, bool need, enum parse_fragment_flags flags)
 {
-    *fragment = (struct fragment) { // Something we can safely deinit
-        .type = FRAG_EXPAND,
-        .expand = NULL,
-    };
+    *fragment = empty_fragment();
 
     struct fragment *lhs = NULL;
     struct fragment *rhs = NULL;
@@ -2242,8 +2259,8 @@ parse_fragment(apfl_parser_ptr p, struct fragment *fragment, bool need, enum par
         case APFL_TOK_DOUBLE_COLON:
         case APFL_TOK_COLON:
             if (
-                ((lhs = ALLOC_OBJ(p->allocator, struct fragment)) == NULL)
-                || ((rhs = ALLOC_OBJ(p->allocator, struct fragment)) == NULL)
+                ((lhs = new_empty_fragment(p->allocator)) == NULL)
+                || ((rhs = new_empty_fragment(p->allocator)) == NULL)
             ) {
                 p->error = apfl_error_simple(APFL_ERR_MALLOC_FAILED);
                 return PF_ERROR;
diff --git a/src/parser_test.c b/src/parser_test.c
index a0f5ab6..de9feb1 100644
--- a/src/parser_test.c
+++ b/src/parser_test.c
@@ -1584,6 +1584,12 @@ TEST(err_unexpected_assignment_member_access, t) {
     destroy_parser_test(pt);
 }
 
+TEST(err_unexpected_dot_in_nested_pairs, t) {
+    struct parser_test *pt = new_parser_test(t, "1::2::.3");
+    expect_error_of_type(pt, APFL_ERR_UNEXPECTED_TOKEN);
+    destroy_parser_test(pt);
+}
+
 TESTS_BEGIN
     ADDTEST(empty),
     ADDTEST(hello_world),
@@ -1626,4 +1632,5 @@ TESTS_BEGIN
     ADDTEST(err_unexpected_expression_in_member_assignable),
     ADDTEST(err_unexpected_constant_in_member_assignable),
     ADDTEST(err_unexpected_assignment_member_access),
+    ADDTEST(err_unexpected_dot_in_nested_pairs),
 TESTS_END