From 3e6529d202b0b2328d7897eadd64b0c22296bc72 Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Wed, 25 Nov 2015 11:45:16 -0500 Subject: [PATCH] encoding/json: revise docs for Unmarshal into map, slice, array Fixes #12972. Change-Id: Id0611667e6149753c351c0c5e01211340a87d3fd Reviewed-on: https://go-review.googlesource.com/17230 Reviewed-by: David Crawshaw --- src/encoding/json/decode.go | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go index ef08b0c274..6dc1b9d5b6 100644 --- a/src/encoding/json/decode.go +++ b/src/encoding/json/decode.go @@ -48,12 +48,22 @@ import ( // map[string]interface{}, for JSON objects // nil for JSON null // -// To unmarshal a JSON array into a slice, Unmarshal resets the slice to nil -// and then appends each element to the slice. +// To unmarshal a JSON array into a slice, Unmarshal resets the slice length +// to zero and then appends each element to the slice. +// As a special case, to unmarshal an empty JSON array into a slice, +// Unmarshal replaces the slice with a new empty slice. // -// To unmarshal a JSON object into a map, Unmarshal replaces the map -// with an empty map and then adds key-value pairs from the object to -// the map. +// To unmarshal a JSON array into a Go array, Unmarshal decodes +// JSON array elements into corresponding Go array elements. +// If the Go array is smaller than the JSON array, +// the additional JSON array elements are discarded. +// If the JSON array is smaller than the Go array, +// the additional Go array elements are set to zero values. +// +// To unmarshal a JSON object into a string-keyed map, Unmarshal first +// establishes a map to use, If the map is nil, Unmarshal allocates a new map. +// Otherwise Unmarshal reuses the existing map, keeping existing entries. +// Unmarshal then stores key-value pairs from the JSON object into the map. // // If a JSON value is not appropriate for a given target type, // or if a JSON number overflows the target type, Unmarshal -- 2.48.1