reflect: support for struct tag use by multiple packages
Each package using struct field tags assumes that
it is the only package storing data in the tag.
This CL adds support in package reflect for sharing
tags between multiple packages. In this scheme, the
tags must be of the form
key:"value" key2:"value2"
(raw strings help when writing that tag in Go source).
reflect.StructField's Tag field now has type StructTag
(a string type), which has method Get(key string) string
that returns the associated value.
Clients of json and xml will need to be updated.
Code that says
type T struct {
X int "name"
}
should become
type T struct {
X int `json:"name"` // or `xml:"name"`
}
Use govet to identify struct tags that need to be changed
to use the new syntax.
R=r, r, dsymonds, bradfitz, kevlar, fvbommel, n13m3y3r
CC=golang-dev
https://golang.org/cl/4645069
diff --git a/src/pkg/reflect/all_test.go b/src/pkg/reflect/all_test.go
index 94b0fb5..34d74b3 100644
--- a/src/pkg/reflect/all_test.go
+++ b/src/pkg/reflect/all_test.go
@@ -127,17 +127,17 @@
},
{struct {
x struct {
- a int8 "hi there"
+ a int8 `reflect:"hi there"`
}
}{},
- `struct { a int8 "hi there" }`,
+ `struct { a int8 "reflect:\"hi there\"" }`,
},
{struct {
x struct {
- a int8 "hi \x00there\t\n\"\\"
+ a int8 `reflect:"hi \x00there\t\n\"\\"`
}
}{},
- `struct { a int8 "hi \x00there\t\n\"\\" }`,
+ `struct { a int8 "reflect:\"hi \\x00there\\t\\n\\\"\\\\\"" }`,
},
{struct {
x struct {
@@ -423,7 +423,7 @@
// make sure tag strings are not part of element type
typ = TypeOf(struct {
- d []uint32 "TAG"
+ d []uint32 `reflect:"TAG"`
}{}).Field(0).Type
testType(t, 14, typ, "[]uint32")
}
@@ -1544,3 +1544,23 @@
t.Errorf("after Fprintf CallSlice: %q != %q", b.String(), "hello 42 world")
}
}
+
+var tagGetTests = []struct {
+ Tag StructTag
+ Key string
+ Value string
+}{
+ {`protobuf:"PB(1,2)"`, `protobuf`, `PB(1,2)`},
+ {`protobuf:"PB(1,2)"`, `foo`, ``},
+ {`protobuf:"PB(1,2)"`, `rotobuf`, ``},
+ {`protobuf:"PB(1,2)" json:"name"`, `json`, `name`},
+ {`protobuf:"PB(1,2)" json:"name"`, `protobuf`, `PB(1,2)`},
+}
+
+func TestTagGet(t *testing.T) {
+ for _, tt := range tagGetTests {
+ if v := tt.Tag.Get(tt.Key); v != tt.Value {
+ t.Errorf("StructTag(%#q).Get(%#q) = %#q, want %#q", tt.Tag, tt.Key, v, tt.Value)
+ }
+ }
+}
