From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp38.i.mail.ru (smtp38.i.mail.ru [94.100.177.98]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 84420446439 for ; Fri, 9 Oct 2020 01:00:00 +0300 (MSK) From: Roman Khabibov Date: Fri, 9 Oct 2020 00:59:56 +0300 Message-Id: <20201008215956.93983-3-roman.habibov@tarantool.org> In-Reply-To: <20201008215956.93983-1-roman.habibov@tarantool.org> References: <20201008215956.93983-1-roman.habibov@tarantool.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Tarantool-patches] [PATCH 2/2] json: print context in error mesages List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: tarantool-patches@dev.tarantool.org Context is just a string with a few characters before and after wrong token, wrong token itself and a symbolic arrow pointing to this token. Closes #4339 --- test/app-tap/json.test.lua | 20 ++++++++++- third_party/lua-cjson/lua_cjson.c | 59 ++++++++++++++++++++++++++++--- 2 files changed, 73 insertions(+), 6 deletions(-) diff --git a/test/app-tap/json.test.lua b/test/app-tap/json.test.lua index 6d511e686..70e9f6cf7 100755 --- a/test/app-tap/json.test.lua +++ b/test/app-tap/json.test.lua @@ -22,7 +22,7 @@ end tap.test("json", function(test) local serializer = require('json') - test:plan(51) + test:plan(57) test:test("unsigned", common.test_unsigned, serializer) test:test("signed", common.test_signed, serializer) @@ -184,4 +184,22 @@ tap.test("json", function(test) test:ok(string.find(err_msg, 'comma') ~= nil, 'comma instead of T_COMMA') _, err_msg = pcall(serializer.decode, '{') test:ok(string.find(err_msg, 'end') ~= nil, 'end instead of T_END') + + -- + -- gh-4339: Make sure that context is printed. + -- + _, err_msg = pcall(serializer.decode, '{{: "world"}') + test:ok(string.find(err_msg, '{ >> {: "worl') ~= nil, 'context #1') + _, err_msg = pcall(serializer.decode, '{"a": "world"}}') + test:ok(string.find(err_msg, '"world"} >> }') ~= nil, 'context #2') + _, err_msg = pcall(serializer.decode, '{1: "world"}') + test:ok(string.find(err_msg, '{ >> 1: "worl') ~= nil, 'context #3') + _, err_msg = pcall(serializer.decode, '{') + test:ok(string.find(err_msg, '{ >> ') ~= nil, 'context #4') + _, err_msg = pcall(serializer.decode, '}') + test:ok(string.find(err_msg, ' >> }') ~= nil, 'context #5') + serializer.cfg{decode_max_depth = 1} + _, err_msg = pcall(serializer.decode, '{"a": {a = {}}}') + test:ok(string.find(err_msg, '{"a": >> {a = {}}') ~= nil, 'context #6') + end) diff --git a/third_party/lua-cjson/lua_cjson.c b/third_party/lua-cjson/lua_cjson.c index 33cf30577..f9e06172d 100644 --- a/third_party/lua-cjson/lua_cjson.c +++ b/third_party/lua-cjson/lua_cjson.c @@ -831,6 +831,48 @@ static void json_next_token(json_parse_t *json, json_token_t *token) json_set_token_error(token, json, "invalid token"); } +enum context_length { + CONTEXT_ARROW_LENGTH = 4, + CONTEXT_MAX_LENGTH_BEFORE = 8, + CONTEXT_MAX_LENGTH_AFTER = 8, + CONTEXT_MAX_LENGTH = CONTEXT_MAX_LENGTH_BEFORE + CONTEXT_MAX_LENGTH_AFTER + + CONTEXT_ARROW_LENGTH, +}; + +/** + * Copy characters near wrong token with the position @a + * column_index to a static string buffer @a context and lay out + * arrow " >> " before this token. + * + * @param context String static buffer to fill. + * @param json Structure with pointers to parsing string. + * @param column_index Position of wrong token in the current + * line. + */ +static void fill_context(char *context, json_parse_t *json, int column_index) +{ + assert(column_index >= 0); + int length_before = column_index < CONTEXT_MAX_LENGTH_BEFORE ? + column_index : CONTEXT_MAX_LENGTH_BEFORE; + const char *src = json->cur_line_ptr + column_index - length_before; + /* Fill context before the arrow. */ + memcpy(context, src, length_before); + context += length_before; + src += length_before; + + /* Make the arrow. */ + *(context++) = ' '; + memset(context, '>', CONTEXT_ARROW_LENGTH - 2); + context += CONTEXT_ARROW_LENGTH - 2; + *(context++) = ' '; + + /* Fill context after the arrow. */ + const char *end = context + CONTEXT_MAX_LENGTH_AFTER; + for (; context < end && *src != '\0' && *src != '\n'; ++src, ++context) + *context = *src; + *context = '\0'; +} + /* This function does not return. * DO NOT CALL WITH DYNAMIC MEMORY ALLOCATED. * The only supported exception is the temporary parser string @@ -849,9 +891,13 @@ static void json_throw_parse_error(lua_State *l, json_parse_t *json, else found = json_token_type_name[token->type]; + int column_index = token->column_index; + char context[CONTEXT_MAX_LENGTH + 1]; + fill_context(context, json, column_index); + /* Note: token->column_index is 0 based, display starting from 1 */ - luaL_error(l, "Expected %s but found %s on line %d at character %d", exp, - found, json->line_count, token->column_index + 1); + luaL_error(l, "Expected %s but found %s on line %d at character %d here " + "'%s'", exp, found, json->line_count, column_index + 1, context); } static inline void json_decode_ascend(json_parse_t *json) @@ -868,10 +914,13 @@ static void json_decode_descend(lua_State *l, json_parse_t *json, int slots) return; } + char context[CONTEXT_MAX_LENGTH + 1]; + fill_context(context, json, json->ptr - json->cur_line_ptr - 1); + strbuf_free(json->tmp); - luaL_error(l, "Found too many nested data structures (%d) on line %d at " - "character %d", json->current_depth, json->line_count, - json->ptr - json->cur_line_ptr); + luaL_error(l, "Found too many nested data structures (%d) on line %d at cha" + "racter %d here '%s'", json->current_depth, json->line_count, + json->ptr - json->cur_line_ptr, context); } static void json_parse_object_context(lua_State *l, json_parse_t *json) -- 2.24.3 (Apple Git-128)