From 5d12434eee031e3db9e0bfe753c663b565b6a0f9 Mon Sep 17 00:00:00 2001 From: Alexey Vilenskiy Date: Fri, 14 Aug 2020 11:37:31 +0300 Subject: [PATCH] reflect: support multiple keys in struct tags Fixes #40281 Change-Id: Ie624bce3a78a06d7ed71bba1f501e66802dffd13 Reviewed-on: https://go-review.googlesource.com/c/go/+/248341 Reviewed-by: Ian Lance Taylor Trust: Dmitri Shuralyov --- src/reflect/all_test.go | 170 ++++++++++++++++++++++++++++++++++++++++ src/reflect/type.go | 27 ++++++- 2 files changed, 194 insertions(+), 3 deletions(-) diff --git a/src/reflect/all_test.go b/src/reflect/all_test.go index 0684eab973..a12712d254 100644 --- a/src/reflect/all_test.go +++ b/src/reflect/all_test.go @@ -7165,6 +7165,176 @@ func TestMapIterDelete1(t *testing.T) { } } +func TestStructTagLookup(t *testing.T) { + var tests = []struct { + tag StructTag + key string + expectedValue string + expectedOK bool + }{ + { + tag: `json:"json_value_1"`, + key: "json", + expectedValue: "json_value_1", + expectedOK: true, + }, + { + tag: `json:"json_value_2" xml:"xml_value_2"`, + key: "json", + expectedValue: "json_value_2", + expectedOK: true, + }, + { + tag: `json:"json_value_3" xml:"xml_value_3"`, + key: "xml", + expectedValue: "xml_value_3", + expectedOK: true, + }, + { + tag: `bson json:"shared_value_4"`, + key: "json", + expectedValue: "shared_value_4", + expectedOK: true, + }, + { + tag: `bson json:"shared_value_5"`, + key: "bson", + expectedValue: "shared_value_5", + expectedOK: true, + }, + { + tag: `json bson xml form:"field_1,omitempty" other:"value_1"`, + key: "xml", + expectedValue: "field_1,omitempty", + expectedOK: true, + }, + { + tag: `json bson xml form:"field_2,omitempty" other:"value_2"`, + key: "form", + expectedValue: "field_2,omitempty", + expectedOK: true, + }, + { + tag: `json bson xml form:"field_3,omitempty" other:"value_3"`, + key: "other", + expectedValue: "value_3", + expectedOK: true, + }, + { + tag: `json bson xml form:"field_4" other:"value_4"`, + key: "json", + expectedValue: "field_4", + expectedOK: true, + }, + { + tag: `json bson xml form:"field_5" other:"value_5"`, + key: "non_existing", + expectedValue: "", + expectedOK: false, + }, + { + tag: `json "json_6"`, + key: "json", + expectedValue: "", + expectedOK: false, + }, + { + tag: `json:"json_7" bson "bson_7"`, + key: "json", + expectedValue: "json_7", + expectedOK: true, + }, + { + tag: `json:"json_8" xml "xml_8"`, + key: "xml", + expectedValue: "", + expectedOK: false, + }, + { + tag: `json bson xml form "form_9" other:"value_9"`, + key: "bson", + expectedValue: "", + expectedOK: false, + }, + { + tag: `json bson xml form "form_10" other:"value_10"`, + key: "other", + expectedValue: "", + expectedOK: false, + }, + { + tag: `json bson xml form:"form_11" other "value_11"`, + key: "json", + expectedValue: "form_11", + expectedOK: true, + }, + { + tag: `tag1`, + key: "tag1", + expectedValue: "", + expectedOK: false, + }, + { + tag: `tag2 :"hello_2"`, + key: "tag2", + expectedValue: "", + expectedOK: false, + }, + { + tag: `tag3: "hello_3"`, + key: "tag3", + expectedValue: "", + expectedOK: false, + }, + { + tag: "json\x7fbson: \"hello_4\"", + key: "json", + expectedValue: "", + expectedOK: false, + }, + { + tag: "json\x7fbson: \"hello_5\"", + key: "bson", + expectedValue: "", + expectedOK: false, + }, + { + tag: "json bson:\x7f\"hello_6\"", + key: "json", + expectedValue: "", + expectedOK: false, + }, + { + tag: "json bson:\x7f\"hello_7\"", + key: "bson", + expectedValue: "", + expectedOK: false, + }, + { + tag: "json\x09bson:\"hello_8\"", + key: "json", + expectedValue: "", + expectedOK: false, + }, + { + tag: "a\x7fb json:\"val\"", + key: "json", + expectedValue: "", + expectedOK: false, + }, + } + + for _, test := range tests { + v, ok := test.tag.Lookup(test.key) + if v != test.expectedValue { + t.Errorf("struct tag lookup failed, got %s, want %s", v, test.expectedValue) + } + if ok != test.expectedOK { + t.Errorf("struct tag lookup failed, got %t, want %t", ok, test.expectedOK) + } + } +} + // iterateToString returns the set of elements // returned by an iterator in readable form. func iterateToString(it *MapIter) string { diff --git a/src/reflect/type.go b/src/reflect/type.go index 44c96fea82..a3a616701b 100644 --- a/src/reflect/type.go +++ b/src/reflect/type.go @@ -1130,6 +1130,9 @@ func (tag StructTag) Lookup(key string) (value string, ok bool) { // When modifying this code, also update the validateStructTag code // in cmd/vet/structtag.go. + // keyFound indicates that such key on the left side has already been found. + var keyFound bool + for tag != "" { // Skip leading space. i := 0 @@ -1149,11 +1152,29 @@ func (tag StructTag) Lookup(key string) (value string, ok bool) { for i < len(tag) && tag[i] > ' ' && tag[i] != ':' && tag[i] != '"' && tag[i] != 0x7f { i++ } - if i == 0 || i+1 >= len(tag) || tag[i] != ':' || tag[i+1] != '"' { + if i == 0 || i+1 >= len(tag) || tag[i] < ' ' || tag[i] == 0x7f { break } name := string(tag[:i]) - tag = tag[i+1:] + tag = tag[i:] + + // If we found a space char here - assume that we have a tag with + // multiple keys. + if tag[0] == ' ' { + if name == key { + keyFound = true + } + continue + } + + // Spaces were filtered above so we assume that here we have + // only valid tag value started with `:"`. + if tag[0] != ':' || tag[1] != '"' { + break + } + + // Remove the colon leaving tag at the start of the quoted string. + tag = tag[1:] // Scan quoted string to find value. i = 1 @@ -1169,7 +1190,7 @@ func (tag StructTag) Lookup(key string) (value string, ok bool) { qvalue := string(tag[:i+1]) tag = tag[i+1:] - if key == name { + if key == name || keyFound { value, err := strconv.Unquote(qvalue) if err != nil { break -- 2.48.1