mysql/json: read numbers the way MySQL does

go/mysql/json/LICENSE.rapidjson

@@ -0,0 +1,37 @@
+Tencent is pleased to support the open source community by making RapidJSON
+available.
+
+Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip.
+
+Parts of parser.go are derived from RapidJSON 1.1.0, the JSON parser MySQL
+parses documents with, so that Vitess accepts exactly the documents MySQL does:
+mysqlNumberFits follows GenericReader::ParseNumber in
+include/rapidjson/reader.h, scaleByPow10 and movePoint follow
+StrtodNormalPrecision and FastPath in include/rapidjson/internal/strtod.h, and
+the pow10 table holds the same values as Pow10 in
+include/rapidjson/internal/pow10.h. No RapidJSON source is included here; the Go
+code was written to reproduce what those functions decide.
+
+RapidJSON is licensed under the MIT License:
+
+The MIT License (MIT)
+
+Copyright (C) 2015 THL A29 Limited, a Tencent company, and Milo Yip.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

go/mysql/json/marshal.go

@@ -491,7 +491,7 @@ func (w *sqlWriter) writeNumber(top bool) error {
 	// Use the parser's readFloat to validate number grammar, rejecting
 	// malformed inputs like "1+2", "1..2", or "1e+" that a simple
 	// character-class loop would accept.
-	n, ok := readFloat(w.data[w.pos:])
+	n, _, ok := readFloat(w.data[w.pos:])
 	if !ok || n == 0 {
 		return fmt.Errorf("invalid number at position %d in JSON", w.pos)
 	}