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Revert "reflect: support multiple keys in struct tags"

Proposal #40281 was initially accepted, but has now been declined.
This CL removes most of the work done to implement it.

Specifically this reverts CLs 248341, 274448, 274474, and 278392.

For #40281
For #43226

Change-Id: I5a9ebb4d9cb5fb0962434b64c59beb8343030be5
Reviewed-on: https://go-review.googlesource.com/c/go/+/281515
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emmanuel@orijtech.com>
This commit is contained in:
Ian Lance Taylor 2021-01-06 14:32:03 -08:00
parent 091414b5b7
commit 9ec21a8f34
3 changed files with 9 additions and 215 deletions

View File

@ -845,17 +845,6 @@ func TestFoo(t *testing.T) {
</dd>
</dl><!-- path/filepath -->
<dl id="reflect"><dt><a href="/pkg/reflect/">reflect</a></dt>
<dd>
<p><!-- CL 248341, golang.org/issues/40281 -->
<a href="/pkg/reflect/#StructTag"><code>StructTag</code></a>
now allows multiple space-separated keys in key:value pairs,
as in <code>`json xml:"field1"`</code> (equivalent to
<code>`json:"field1" xml:"field1"`</code>).
</p>
</dd>
</dl><!-- reflect -->
<dl id="runtime/debug"><dt><a href="/pkg/runtime/debug/">runtime/debug</a></dt>
<dd>
<p><!-- CL 249677 -->

View File

@ -7168,176 +7168,6 @@ 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 {

View File

@ -1104,16 +1104,12 @@ type StructField struct {
// A StructTag is the tag string in a struct field.
//
// By convention, tag strings are a mapping of keys to values.
// The format is key:"value". Each key is a non-empty string consisting
// of non-control characters other than space (U+0020 ' '),
// quote (U+0022 '"'), and colon (U+003A ':'). Each value is quoted
// using U+0022 '"' characters and Go string literal syntax.
// Multiple key-value mappings are separated by zero or more spaces, as in
// key1:"value1" key2:"value2"
// Multiple keys may map to a single shared value by separating the keys
// with spaces, as in
// key1 key2:"value"
// By convention, tag strings are a concatenation of
// optionally space-separated key:"value" pairs.
// Each key is a non-empty string consisting of non-control
// characters other than space (U+0020 ' '), quote (U+0022 '"'),
// and colon (U+003A ':'). Each value is quoted using U+0022 '"'
// characters and Go string literal syntax.
type StructTag string
// Get returns the value associated with key in the tag string.
@ -1136,9 +1132,6 @@ 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
@ -1158,29 +1151,11 @@ 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] == 0x7f {
if i == 0 || i+1 >= len(tag) || tag[i] != ':' || tag[i+1] != '"' {
break
}
name := string(tag[:i])
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:]
tag = tag[i+1:]
// Scan quoted string to find value.
i = 1
@ -1196,7 +1171,7 @@ func (tag StructTag) Lookup(key string) (value string, ok bool) {
qvalue := string(tag[:i+1])
tag = tag[i+1:]
if key == name || keyFound {
if key == name {
value, err := strconv.Unquote(qvalue)
if err != nil {
break