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Merged
byroot merged 1 commit into from
Jun 23, 2025
Merged

Deprecate duplicate keys in object #818

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3 changes: 3 additions & 0 deletions CHANGES.md
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,9 @@

### Unreleased

* Add bnew `allow_duplicate_key` parsing options. By default a warning is now emitted when a duplicated key is encountered.
In `json 3.0` an error will be raised.

### 2025-05-23 (2.12.2)

* Fix compiler optimization level.
Expand Down
72 changes: 59 additions & 13 deletions ext/json/ext/parser/parser.c
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,7 @@ static ID i_chr, i_aset, i_aref,
i_leftshift, i_new, i_try_convert, i_uminus, i_encode;

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

static int binary_encindex;
static int utf8_encindex;
Expand Down Expand Up @@ -363,10 +363,17 @@ static int convert_UTF32_to_UTF8(char *buf, uint32_t ch)
return len;
}

enum duplicate_key_action {
JSON_DEPRECATED = 0,
JSON_IGNORE,
JSON_RAISE,
};

typedef struct JSON_ParserStruct {
VALUE on_load_proc;
VALUE decimal_class;
ID decimal_method_id;
enum duplicate_key_action on_duplicate_key;
int max_nesting;
bool allow_nan;
bool allow_trailing_comma;
Expand All @@ -386,15 +393,8 @@ typedef struct JSON_ParserStateStruct {
int current_nesting;
} JSON_ParserState;


#define PARSE_ERROR_FRAGMENT_LEN 32
#ifdef RBIMPL_ATTR_NORETURN
RBIMPL_ATTR_NORETURN()
#endif
static void raise_parse_error(const char *format, JSON_ParserState *state)
static void cursor_position(JSON_ParserState *state, long *line_out, long *column_out)
{
unsigned char buffer[PARSE_ERROR_FRAGMENT_LEN + 3];

const char *cursor = state->cursor;
long column = 0;
long line = 1;
Expand All @@ -411,6 +411,27 @@ static void raise_parse_error(const char *format, JSON_ParserState *state)
line++;
}
}
*line_out = line;
*column_out = column;
}

static void emit_parse_warning(const char *message, JSON_ParserState *state)
{
long line, column;
cursor_position(state, &line, &column);

rb_warn("%s at line %ld column %ld", message, line, column);
}

#define PARSE_ERROR_FRAGMENT_LEN 32
#ifdef RBIMPL_ATTR_NORETURN
RBIMPL_ATTR_NORETURN()
#endif
static void raise_parse_error(const char *format, JSON_ParserState *state)
{
unsigned char buffer[PARSE_ERROR_FRAGMENT_LEN + 3];
long line, column;
cursor_position(state, &line, &column);

const char *ptr = "EOF";
if (state->cursor && state->cursor < state->end) {
Expand Down Expand Up @@ -807,11 +828,25 @@ static inline VALUE json_decode_array(JSON_ParserState *state, JSON_ParserConfig
return array;
}

static inline VALUE json_decode_object(JSON_ParserState *state, JSON_ParserConfig *config, long count)
static inline VALUE json_decode_object(JSON_ParserState *state, JSON_ParserConfig *config, size_t count)
{
VALUE object = rb_hash_new_capa(count);
size_t entries_count = count / 2;
VALUE object = rb_hash_new_capa(entries_count);
rb_hash_bulk_insert(count, rvalue_stack_peek(state->stack, count), object);

if (RB_UNLIKELY(RHASH_SIZE(object) < entries_count)) {
switch (config->on_duplicate_key) {
case JSON_IGNORE:
break;
case JSON_DEPRECATED:
emit_parse_warning("detected duplicate keys in JSON object. This will raise an error in json 3.0 unless enabled via `allow_duplicate_key: true`", state);
break;
case JSON_RAISE:
raise_parse_error("duplicate key", state);
break;
}
}

rvalue_stack_pop(state->stack, count);

if (config->freeze) {
Expand Down Expand Up @@ -1060,6 +1095,8 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)
break;
}
case '{': {
const char *object_start_cursor = state->cursor;

state->cursor++;
json_eat_whitespace(state);
long stack_head = state->stack->head;
Expand Down Expand Up @@ -1094,8 +1131,15 @@ static VALUE json_parse_any(JSON_ParserState *state, JSON_ParserConfig *config)
if (*state->cursor == '}') {
state->cursor++;
state->current_nesting--;
long count = state->stack->head - stack_head;
return json_push_value(state, config, json_decode_object(state, config, count));
size_t count = state->stack->head - stack_head;

// Temporary rewind cursor in case an error is raised
const char *final_cursor = state->cursor;
state->cursor = object_start_cursor;
VALUE object = json_decode_object(state, config, count);
state->cursor = final_cursor;

return json_push_value(state, config, object);
}

if (*state->cursor == ',') {
Expand Down Expand Up @@ -1184,6 +1228,7 @@ static int parser_config_init_i(VALUE key, VALUE val, VALUE data)
else if (key == sym_symbolize_names) { config->symbolize_names = RTEST(val); }
else if (key == sym_freeze) { config->freeze = RTEST(val); }
else if (key == sym_on_load) { config->on_load_proc = RTEST(val) ? val : Qfalse; }
else if (key == sym_allow_duplicate_key) { config->on_duplicate_key = RTEST(val) ? JSON_IGNORE : JSON_RAISE; }
else if (key == sym_decimal_class) {
if (RTEST(val)) {
if (rb_respond_to(val, i_try_convert)) {
Expand Down Expand Up @@ -1400,6 +1445,7 @@ void Init_parser(void)
sym_freeze = ID2SYM(rb_intern("freeze"));
sym_on_load = ID2SYM(rb_intern("on_load"));
sym_decimal_class = ID2SYM(rb_intern("decimal_class"));
sym_allow_duplicate_key = ID2SYM(rb_intern("allow_duplicate_key"));

i_chr = rb_intern("chr");
i_aset = rb_intern("[]=");
Expand Down
7 changes: 7 additions & 0 deletions java/src/json/ext/OptionsReader.java
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Expand Up @@ -53,6 +53,13 @@ IRubyObject get(String key) {
return opts == null ? null : opts.fastARef(runtime.newSymbol(key));
}

boolean hasKey(String key) {
if (opts == null) {
return false;
}
return opts.hasKey(runtime.newSymbol(key));
}

boolean getBool(String key, boolean defaultValue) {
IRubyObject value = get(key);
return value == null ? defaultValue : value.isTrue();
Expand Down
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