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Merged
byroot merged 1 commit into from
Jun 7, 2026
+280 −147
Merged

Deprecate default support of JavaScript comments in the parser #1001

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1 change: 1 addition & 0 deletions CHANGES.md
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@

### Unreleased

* Deprecate default support of JavaScript comments in the parser and add `allow_comments: true` parsing option.
* Integrate with Ruby 4.1 `ruby_sized_xfree`.

### 2026-06-03 (2.19.8)
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59 changes: 37 additions & 22 deletions ext/json/ext/parser/parser.c
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Original file line number Diff line number Diff line change
Expand Up @@ -7,9 +7,9 @@ static VALUE CNaN, CInfinity, CMinusInfinity;

static ID i_new, i_try_convert, i_uminus, i_encode;

static VALUE sym_max_nesting, sym_allow_nan, sym_allow_trailing_comma, sym_allow_control_characters,
sym_allow_invalid_escape, sym_symbolize_names, sym_freeze, sym_decimal_class, sym_on_load,
sym_allow_duplicate_key;
static VALUE sym_max_nesting, sym_allow_nan, sym_allow_trailing_comma, sym_allow_comments,
sym_allow_control_characters, sym_allow_invalid_escape, sym_symbolize_names,
sym_freeze, sym_decimal_class, sym_on_load, sym_allow_duplicate_key;

static int binary_encindex;
static int utf8_encindex;
Expand Down Expand Up @@ -382,7 +382,7 @@ typedef struct json_frame_stack_struct {
json_frame *ptr;
} json_frame_stack;

enum duplicate_key_action {
enum deprecatable_action {
JSON_DEPRECATED = 0,
JSON_IGNORE,
JSON_RAISE,
Expand All @@ -392,7 +392,8 @@ typedef struct JSON_ParserStruct {
VALUE on_load_proc;
VALUE decimal_class;
ID decimal_method_id;
enum duplicate_key_action on_duplicate_key;
enum deprecatable_action on_duplicate_key;
enum deprecatable_action on_comment;
int max_nesting;
bool allow_nan;
bool allow_trailing_comma;
Expand Down Expand Up @@ -590,6 +591,8 @@ static void cursor_position(JSON_ParserState *state, long *line_out, long *colum
*column_out = column;
}

static const unsigned int MAX_DEPRECATIONS = 5;

static void emit_parse_warning(const char *message, JSON_ParserState *state)
{
long line, column;
Expand Down Expand Up @@ -707,9 +710,14 @@ static uint32_t unescape_unicode(JSON_ParserState *state, const char *sp, const

static const rb_data_type_t JSON_ParserConfig_type;

const char *COMMENT_DEPRECATION_MESSAGE = "Encountered comment in JSON. This will raise an error in json 3.0 unless enabled via `allow_comments: true`";
NOINLINE(static) void
json_eat_comments(JSON_ParserState *state)
json_eat_comments(JSON_ParserState *state, JSON_ParserConfig *config)
{
if (config->on_comment == JSON_RAISE) {
raise_parse_error("unexpected token %s", state);
}

const char *start = state->cursor;
state->cursor++;

Expand Down Expand Up @@ -744,10 +752,15 @@ json_eat_comments(JSON_ParserState *state)
raise_parse_error_at("unexpected token %s", state, start);
break;
}

if (config->on_comment == JSON_DEPRECATED && state->emitted_deprecations < MAX_DEPRECATIONS) {
state->emitted_deprecations++;
emit_parse_warning(COMMENT_DEPRECATION_MESSAGE, state);
}
}

ALWAYS_INLINE(static) void
json_eat_whitespace(JSON_ParserState *state)
json_eat_whitespace(JSON_ParserState *state, JSON_ParserConfig *config)
{
while (true) {
switch (peek(state)) {
Expand Down Expand Up @@ -778,7 +791,7 @@ json_eat_whitespace(JSON_ParserState *state)
state->cursor++;
break;
case '/':
json_eat_comments(state);
json_eat_comments(state, config);
break;

default:
Expand Down Expand Up @@ -1127,9 +1140,9 @@ NOINLINE(static) void json_on_duplicate_key(JSON_ParserState *state, JSON_Parser

case JSON_DEPRECATED:
// Only emit the first few deprecations to avoid spamming.
if (state->emitted_deprecations < 5) {
emit_duplicate_key_warning(state, json_find_duplicated_key(count, pairs));
if (state->emitted_deprecations < MAX_DEPRECATIONS) {
state->emitted_deprecations++;
emit_duplicate_key_warning(state, json_find_duplicated_key(count, pairs));
}
return;

Expand Down Expand Up @@ -1498,7 +1511,7 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)
}

JSON_PHASE_VALUE: {
json_eat_whitespace(state);
json_eat_whitespace(state, config);

VALUE value;
switch (peek(state)) {
Expand Down Expand Up @@ -1559,7 +1572,7 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)

case '[': {
state->cursor++;
json_eat_whitespace(state);
json_eat_whitespace(state, config);

if (peek(state) == ']') {
state->cursor++;
Expand All @@ -1585,7 +1598,7 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)
const char *object_start_cursor = state->cursor;

state->cursor++;
json_eat_whitespace(state);
json_eat_whitespace(state, config);

if (peek(state) == '}') {
state->cursor++;
Expand Down Expand Up @@ -1632,7 +1645,7 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)
JSON_PHASE_OBJECT_KEY: {
JSON_ASSERT(frame->type == JSON_FRAME_OBJECT);

json_eat_whitespace(state);
json_eat_whitespace(state, config);

if (RB_LIKELY(peek(state) == '"')) {
json_push_value(state, config, json_parse_string(state, config, true));
Expand All @@ -1654,7 +1667,7 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)
JSON_PHASE_OBJECT_COLON: {
JSON_ASSERT(frame->type == JSON_FRAME_OBJECT);

json_eat_whitespace(state);
json_eat_whitespace(state, config);

if (RB_LIKELY(peek(state) == ':')) {
state->cursor++;
Expand All @@ -1675,14 +1688,14 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)
JSON_PHASE_ARRAY_COMMA: {
JSON_ASSERT(frame->type == JSON_FRAME_ARRAY);

json_eat_whitespace(state);
json_eat_whitespace(state, config);

const char next_char = peek(state);

if (RB_LIKELY(next_char == ',')) {
state->cursor++;
if (config->allow_trailing_comma) {
json_eat_whitespace(state);
json_eat_whitespace(state, config);
if (peek(state) == ']') {
// Trailing comma: stay in COMMA to close on the next iteration.
goto JSON_PHASE_ARRAY_COMMA;
Expand Down Expand Up @@ -1717,14 +1730,14 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)
JSON_PHASE_OBJECT_COMMA: {
JSON_ASSERT(frame->type == JSON_FRAME_OBJECT);

json_eat_whitespace(state);
json_eat_whitespace(state, config);
const char next_char = peek(state);

if (RB_LIKELY(next_char == ',')) {
state->cursor++;

if (config->allow_trailing_comma) {
json_eat_whitespace(state);
json_eat_whitespace(state, config);
if (peek(state) == '}') {
// Trailing comma: stay in COMMA to close on the next iteration.
goto JSON_PHASE_OBJECT_COMMA;
Expand Down Expand Up @@ -1766,9 +1779,9 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)
JSON_UNREACHABLE_RETURN(Qundef);
}

static void json_ensure_eof(JSON_ParserState *state)
static void json_ensure_eof(JSON_ParserState *state, JSON_ParserConfig *config)
{
json_eat_whitespace(state);
json_eat_whitespace(state, config);
if (!eos(state)) {
raise_parse_error("unexpected token at end of stream %s", state);
}
Expand Down Expand Up @@ -1825,6 +1838,7 @@ static int parser_config_init_i(VALUE key, VALUE val, VALUE data)
if (key == sym_max_nesting) { config->max_nesting = RTEST(val) ? FIX2INT(val) : 0; }
else if (key == sym_allow_nan) { config->allow_nan = RTEST(val); }
else if (key == sym_allow_trailing_comma) { config->allow_trailing_comma = RTEST(val); }
else if (key == sym_allow_comments) { config->on_comment = RTEST(val) ? JSON_IGNORE : JSON_RAISE; }
else if (key == sym_allow_control_characters) { config->allow_control_characters = RTEST(val); }
else if (key == sym_allow_invalid_escape) { config->allow_invalid_escape = RTEST(val); }
else if (key == sym_symbolize_names) { config->symbolize_names = RTEST(val); }
Expand Down Expand Up @@ -1977,7 +1991,7 @@ static VALUE cParser_parse(JSON_ParserConfig *config, VALUE src)
RB_GC_GUARD(value_stack_handle);
RB_GC_GUARD(frame_stack_handle);
RB_GC_GUARD(Vsource);
json_ensure_eof(state);
json_ensure_eof(state, config);

return result;
}
Expand Down Expand Up @@ -2079,6 +2093,7 @@ void Init_parser(void)
sym_max_nesting = ID2SYM(rb_intern("max_nesting"));
sym_allow_nan = ID2SYM(rb_intern("allow_nan"));
sym_allow_trailing_comma = ID2SYM(rb_intern("allow_trailing_comma"));
sym_allow_comments = ID2SYM(rb_intern("allow_comments"));
sym_allow_control_characters = ID2SYM(rb_intern("allow_control_characters"));
sym_allow_invalid_escape = ID2SYM(rb_intern("allow_invalid_escape"));
sym_symbolize_names = ID2SYM(rb_intern("symbolize_names"));
Expand Down
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