| 1 | /* |
| 2 | * Unit tests for JSON Parser error recovery |
| 3 | * |
| 4 | * Copyright 2026 Red Hat |
| 5 | * Author: Paolo Bonzini <pbonzini@redhat.com> |
| 6 | * |
| 7 | * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. |
| 8 | * See the COPYING.LIB file in the top-level directory. |
| 9 | */ |
| 10 | |
| 11 | /* |
| 12 | * Missing tests: |
| 13 | * - multiple JSON values in a single stream |
| 14 | * - multiple invocations of json_message_parser_feed() |
| 15 | * (does not really matter much because of how |
| 16 | * json_lexer_feed() is implemented) |
| 17 | * - most JSON types are only covered by check-json.c. |
| 18 | */ |
| 19 | |
| 20 | #include "qemu/osdep.h" |
| 21 | |
| 22 | #include "qapi/error.h" |
| 23 | #include "qobject/qbool.h" |
| 24 | #include "qobject/json-parser.h" |
| 25 | |
| 26 | typedef struct ParseResult { |
| 27 | int errors; |
| 28 | QObject *result; |
| 29 | } ParseResult; |
| 30 | |
| 31 | static void parse_emit(void *opaque, QObject *json, Error *err) |
| 32 | { |
| 33 | ParseResult *r = opaque; |
| 34 | |
| 35 | g_assert_cmpint(!json, !=, !err); |
| 36 | if (err) { |
| 37 | r->errors++; |
| 38 | error_free(err); |
| 39 | } else { |
| 40 | g_assert_null(r->result); |
| 41 | r->result = json; |
| 42 | } |
| 43 | } |
| 44 | |
| 45 | static ParseResult do_parse(const char *input) |
| 46 | { |
| 47 | ParseResult r = { 0, NULL }; |
| 48 | JSONMessageParser parser; |
| 49 | |
| 50 | json_message_parser_init(&parser, parse_emit, &r, NULL); |
| 51 | json_message_parser_feed(&parser, input, strlen(input)); |
| 52 | json_message_parser_flush(&parser); |
| 53 | json_message_parser_destroy(&parser); |
| 54 | return r; |
| 55 | } |
| 56 | |
| 57 | static void check_result(const char *input, int expected_errors, |
| 58 | QType expected_type) |
| 59 | { |
| 60 | ParseResult r = do_parse(input); |
| 61 | |
| 62 | g_assert_cmpint(r.errors, ==, expected_errors); |
| 63 | g_assert_nonnull(r.result); |
| 64 | g_assert_cmpint(qobject_type(r.result), ==, expected_type); |
| 65 | qobject_unref(r.result); |
| 66 | } |
| 67 | |
| 68 | static void check_result_error(const char *input, int expected_errors) |
| 69 | { |
| 70 | ParseResult r = do_parse(input); |
| 71 | |
| 72 | g_assert_cmpint(r.errors, ==, expected_errors); |
| 73 | g_assert_null(r.result); |
| 74 | } |
| 75 | |
| 76 | static void test_simple(void) |
| 77 | { |
| 78 | check_result("false", 0, QTYPE_QBOOL); |
| 79 | } |
| 80 | |
| 81 | static void test_whitespace(void) |
| 82 | { |
| 83 | check_result(" false", 0, QTYPE_QBOOL); |
| 84 | } |
| 85 | |
| 86 | static void test_extra_closing_braces(void) |
| 87 | { |
| 88 | check_result("}}false", 2, QTYPE_QBOOL); |
| 89 | } |
| 90 | |
| 91 | static void test_bad_dict(void) |
| 92 | { |
| 93 | check_result("{ 'abc' }false", 1, QTYPE_QBOOL); |
| 94 | } |
| 95 | |
| 96 | static void test_trailing_comma(void) |
| 97 | { |
| 98 | check_result("[ 'abc', ]false", 1, QTYPE_QBOOL); |
| 99 | } |
| 100 | |
| 101 | static void test_lexer_recovery(void) |
| 102 | { |
| 103 | check_result("\f{}", 1, QTYPE_QDICT); |
| 104 | check_result("\f[]", 1, QTYPE_QLIST); |
| 105 | check_result("\f:false", 2, QTYPE_QBOOL); |
| 106 | check_result("\f,false", 2, QTYPE_QBOOL); |
| 107 | |
| 108 | /* |
| 109 | * Alphabetic characters do not start a new parsing. This is |
| 110 | * slightly weird but it keeps the lexer simple and works well for |
| 111 | * QMP (where valid input is a sequence of dictionaries). |
| 112 | */ |
| 113 | check_result_error("\ffalse", 1); |
| 114 | check_result_error("\f'str'", 1); |
| 115 | check_result_error("\f\"str\"", 1); |
| 116 | } |
| 117 | |
| 118 | static void test_lexer_recovery_nested(void) |
| 119 | { |
| 120 | check_result("{[{\f{}", 1, QTYPE_QDICT); |
| 121 | check_result("{[{\f[]", 1, QTYPE_QLIST); |
| 122 | check_result("{[{\f:false", 2, QTYPE_QBOOL); |
| 123 | check_result("{[{\f,false", 2, QTYPE_QBOOL); |
| 124 | |
| 125 | /* |
| 126 | * As in test_lexer_recovery, these do not produce a successful |
| 127 | * parse after \f. |
| 128 | */ |
| 129 | check_result_error("{[{\ffalse", 1); |
| 130 | check_result_error("{[{\f'str'", 1); |
| 131 | check_result_error("{[{\f\"str\"", 1); |
| 132 | } |
| 133 | |
| 134 | static void test_nested(void) |
| 135 | { |
| 136 | check_result("[{'a']}false", 1, QTYPE_QBOOL); |
| 137 | } |
| 138 | |
| 139 | static void test_nested_multiple(void) |
| 140 | { |
| 141 | check_result("[{'a']}[{'a']}false", 2, QTYPE_QBOOL); |
| 142 | } |
| 143 | |
| 144 | int main(int argc, char **argv) |
| 145 | { |
| 146 | g_test_init(&argc, &argv, NULL); |
| 147 | |
| 148 | g_test_add_func("/json-parser/simple", test_simple); |
| 149 | g_test_add_func("/json-parser/whitespace", test_whitespace); |
| 150 | g_test_add_func("/json-parser/error-recovery/extra-closing-braces", test_extra_closing_braces); |
| 151 | g_test_add_func("/json-parser/error-recovery/bad-dict", test_bad_dict); |
| 152 | g_test_add_func("/json-parser/error-recovery/trailing-comma", test_trailing_comma); |
| 153 | g_test_add_func("/json-parser/error-recovery/lexer", test_lexer_recovery); |
| 154 | g_test_add_func("/json-parser/error-recovery/lexer/nested", test_lexer_recovery_nested); |
| 155 | g_test_add_func("/json-parser/error-recovery/nested", test_nested); |
| 156 | g_test_add_func("/json-parser/error-recovery/nested/multiple", test_nested_multiple); |
| 157 | |
| 158 | return g_test_run(); |
| 159 | } |