commit 6b4ec2264e1d8ba027b85f3883d532c5068be92a
parent 3567b7d751754920b3cc05e61c00365539a7fbaa
Author: skewb1k <skewb1kunix@gmail.com>
Date: Wed, 11 Feb 2026 14:54:57 +0300
feat(stdlib): vim.json.decode() can allow comments #37795
Problem:
`vim.json.decode()` could not parse JSONC (JSON with Comments)
extension, which is commonly used in configuration files.
Solution:
Introduce an `skip_comments` option, which is disabled by default. When
enabled, allows JavaScript-style comments within JSON data.
Diffstat:
5 files changed, 106 insertions(+), 11 deletions(-)
diff --git a/runtime/doc/lua.txt b/runtime/doc/lua.txt
@@ -3433,6 +3433,11 @@ vim.json.decode({str}, {opts}) *vim.json.decode()*
• {luanil}? (`{ object?: boolean, array?: boolean }`, default:
`nil`) Convert `null` in JSON objects and/or arrays to Lua
`nil` instead of |vim.NIL|.
+ • {skip_comments}? (`boolean`, default: `false`) Allows
+ JavaScript-style comments within JSON data. Comments are
+ treated as whitespace and may appear anywhere whitespace is
+ valid in JSON. Supports single-line comments beginning with
+ '//' and block comments enclosed with '/' and '/'.
Return: ~
(`any`)
diff --git a/runtime/doc/news.txt b/runtime/doc/news.txt
@@ -325,6 +325,7 @@ LUA
• |vim.json.encode()| has an `indent` option for pretty-formatting.
• |vim.json.encode()| has an `sort_keys` option.
• |Range:is_empty()| to check if a |vim.Range| is empty.
+• |vim.json.decode()| has an `skip_comments` option.
OPTIONS
diff --git a/runtime/lua/vim/_meta/json.lua b/runtime/lua/vim/_meta/json.lua
@@ -11,15 +11,20 @@ vim.json = {}
--- Convert `null` in JSON objects and/or arrays to Lua `nil` instead of |vim.NIL|.
--- (default: `nil`)
--- @field luanil? { object?: boolean, array?: boolean }
+---
+--- Allows JavaScript-style comments within JSON data. Comments are treated as whitespace and may
+--- appear anywhere whitespace is valid in JSON. Supports single-line comments beginning with '//'
+--- and block comments enclosed with '/*' and '*/'.
+--- (default: `false`)
+--- @field skip_comments? boolean
--- @class vim.json.encode.Opts
--- @inlinedoc
---
---- Escape slash characters "/" in string values.
+--- Escape slash characters "/" in string values.
--- (default: `false`)
--- @field escape_slash? boolean
---
----
--- If non-empty, the returned JSON is formatted with newlines and whitespace, where `indent`
--- defines the whitespace at each nesting level.
--- (default: `""`)
diff --git a/src/cjson/lua_cjson.c b/src/cjson/lua_cjson.c
@@ -85,6 +85,7 @@
#define DEFAULT_ENCODE_NUMBER_PRECISION 16
#define DEFAULT_ENCODE_EMPTY_TABLE_AS_OBJECT 0
#define DEFAULT_DECODE_ARRAY_WITH_ARRAY_MT 0
+#define DEFAULT_DECODE_SKIP_COMMENTS 0
#define DEFAULT_ENCODE_ESCAPE_FORWARD_SLASH 1
#define DEFAULT_ENCODE_SKIP_UNSUPPORTED_VALUE_TYPES 0
#define DEFAULT_ENCODE_INDENT NULL
@@ -206,6 +207,7 @@ typedef struct {
int decode_invalid_numbers;
int decode_max_depth;
int decode_array_with_array_mt;
+ int decode_skip_comments;
int encode_skip_unsupported_value_types;
} json_config_t;
@@ -230,6 +232,7 @@ typedef struct {
bool luanil_object;
/* convert null in json arrays to lua nil instead of vim.NIL */
bool luanil_array;
+ bool skip_comments;
} json_options_t;
typedef struct {
@@ -455,6 +458,18 @@ static int json_cfg_decode_array_with_array_mt(lua_State *l)
}
*/
+/* Configures whether decoder should skip comments */
+/*
+static int json_cfg_decode_skip_comments(lua_State *l)
+{
+ json_config_t *cfg = json_arg_init(l, 1);
+
+ json_enum_option(l, 1, &cfg->decode_skip_comments, NULL, 1);
+
+ return 1;
+}
+*/
+
/* Configure how to treat invalid types */
/*
static int json_cfg_encode_skip_unsupported_value_types(lua_State *l)
@@ -610,6 +625,7 @@ static void json_create_config(lua_State *l)
cfg->encode_number_precision = DEFAULT_ENCODE_NUMBER_PRECISION;
cfg->encode_empty_table_as_object = DEFAULT_ENCODE_EMPTY_TABLE_AS_OBJECT;
cfg->decode_array_with_array_mt = DEFAULT_DECODE_ARRAY_WITH_ARRAY_MT;
+ cfg->decode_skip_comments = DEFAULT_DECODE_SKIP_COMMENTS;
cfg->encode_escape_forward_slash = DEFAULT_ENCODE_ESCAPE_FORWARD_SLASH;
cfg->encode_skip_unsupported_value_types = DEFAULT_ENCODE_SKIP_UNSUPPORTED_VALUE_TYPES;
cfg->encode_indent = DEFAULT_ENCODE_INDENT;
@@ -1569,13 +1585,46 @@ static void json_next_token(json_parse_t *json, json_token_t *token)
const json_token_type_t *ch2token = json->cfg->ch2token;
int ch;
- /* Eat whitespace. */
while (1) {
- ch = (unsigned char)*(json->ptr);
- token->type = ch2token[ch];
- if (token->type != T_WHITESPACE)
+ /* Eat whitespace. */
+ while (1) {
+ ch = (unsigned char)*(json->ptr);
+ token->type = ch2token[ch];
+ if (token->type != T_WHITESPACE)
+ break;
+ json->ptr++;
+ }
+
+ if (!json->options->skip_comments)
break;
- json->ptr++;
+
+ /* Eat comments. */
+ if ((unsigned char)json->ptr[0] != '/' ||
+ ((unsigned char)json->ptr[1] != '/' &&
+ (unsigned char)json->ptr[1] != '*')) {
+ break;
+ }
+
+ if (json->ptr[1] == '/') {
+ /* Handle single-line comment */
+ json->ptr += 2;
+ while (*json->ptr != '\0' && *json->ptr != '\n')
+ json->ptr++;
+ } else {
+ /* Handle multi-line comment */
+ json->ptr += 2;
+ while (1) {
+ if (*json->ptr == '\0') {
+ json_set_token_error(token, json, "unclosed multi-line comment");
+ return;
+ }
+ if (json->ptr[0] == '*' && json->ptr[1] == '/') {
+ json->ptr += 2;
+ break;
+ }
+ json->ptr++;
+ }
+ }
}
/* Store location of new token. Required when throwing errors
@@ -1821,8 +1870,7 @@ static int json_decode(lua_State *l)
{
json_parse_t json;
json_token_t token;
- json_options_t options = { .luanil_object = false, .luanil_array = false };
-
+ json_options_t options = { .luanil_object = false, .luanil_array = false, .skip_comments = false };
size_t json_len;
@@ -1831,9 +1879,12 @@ static int json_decode(lua_State *l)
break;
case 2:
luaL_checktype(l, 2, LUA_TTABLE);
- lua_getfield(l, 2, "luanil");
- /* We only handle the luanil option for now */
+ lua_getfield(l, 2, "skip_comments");
+ options.skip_comments = lua_toboolean(l, -1);
+ lua_pop(l, 1);
+
+ lua_getfield(l, 2, "luanil");
if (lua_isnil(l, -1)) {
lua_pop(l, 1);
break;
@@ -1951,6 +2002,7 @@ int lua_cjson_new(lua_State *l)
/*
{ "encode_empty_table_as_object", json_cfg_encode_empty_table_as_object },
{ "decode_array_with_array_mt", json_cfg_decode_array_with_array_mt },
+ { "decode_skip_comments", json_cfg_decode_skip_comments },
{ "encode_sparse_array", json_cfg_encode_sparse_array },
{ "encode_max_depth", json_cfg_encode_max_depth },
{ "decode_max_depth", json_cfg_decode_max_depth },
diff --git a/test/functional/lua/json_spec.lua b/test/functional/lua/json_spec.lua
@@ -146,6 +146,38 @@ describe('vim.json.decode()', function()
local str = ('%s{%s"key"%s:%s[%s"val"%s,%s"val2"%s]%s,%s"key2"%s:%s1%s}%s'):gsub('%%s', s)
eq({ key = { 'val', 'val2' }, key2 = 1 }, exec_lua([[return vim.json.decode(...)]], str))
end)
+
+ it('skip_comments', function()
+ eq({}, exec_lua([[return vim.json.decode('{//comment\n}', { skip_comments = true })]]))
+ eq({}, exec_lua([[return vim.json.decode('{//comment\r\n}', { skip_comments = true })]]))
+ eq(
+ 'test // /* */ string',
+ exec_lua(
+ [[return vim.json.decode('"test // /* */ string"//comment', { skip_comments = true })]]
+ )
+ )
+ eq(
+ {},
+ exec_lua([[return vim.json.decode('{/* A multi-line\ncomment*/}', { skip_comments = true })]])
+ )
+ eq(
+ { a = 1 },
+ exec_lua([[return vim.json.decode('{"a" /* Comment */: 1}', { skip_comments = true })]])
+ )
+ eq(
+ { a = 1 },
+ exec_lua([[return vim.json.decode('{"a": /* Comment */ 1}', { skip_comments = true })]])
+ )
+ eq({}, exec_lua([[return vim.json.decode('/*first*//*second*/{}', { skip_comments = true })]]))
+ eq(
+ 'Expected the end but found unclosed multi-line comment at character 13',
+ pcall_err(exec_lua, [[return vim.json.decode('{}/*Unclosed', { skip_comments = true })]])
+ )
+ eq(
+ 'Expected comma or object end but found T_INTEGER at character 12',
+ pcall_err(exec_lua, [[return vim.json.decode('{"a":1/*x*/0}', { skip_comments = true })]])
+ )
+ end)
end)
describe('vim.json.encode()', function()
