Read and write unions under deepObject

docs/client.md

@@ -254,6 +254,7 @@ bracket form most form APIs read, Stripe's among them: a bracket per level, an i
 | `[{price: p1}]` | `items[0][price]=p1` |
 | `{a: {b: [1]}}` | `filter[a][b][0]=1` |
 | `https://x.test`, one value | `url=https%3A%2F%2Fx.test` |
+| a union, `{gte: 1}` or `1` | `created[gte]=1` or `created=1` |
 
 Brackets are shown as they read. On the wire they are `%5B` and `%5D`.
 

docs/server.md

@@ -102,13 +102,17 @@ OpenAPI defines `deepObject` for an object of scalars only. Lists, nesting and s
 [the bracket form](client.md#deepobject-past-an-object) of the client. The server also reads `[]`
 and a repeated bare name: `expand[]=a`, `expand=a&expand=b`.
 
+A union reads keys with brackets as an object member and a bare name as one value: `created[gte]=1`
+and `created=1` both work. A `deepObject` parameter that comes both ways, `created=1&created[gte]=1`,
+is a 400.
+
 ### Parameters without a field
 
 Some parameters cannot be read, so they get no field. Generation warns about each one.
 
 | Parameter | Warning |
 |---|---|
-| a query, header or cookie parameter whose union has an object or array variant, or a list or map of such unions. No style writes it as text. | `param-unsupported` |
+| a query, header or cookie parameter whose union has an object or array variant, or a list or map of such unions. No style but `deepObject` writes it. | `param-unsupported` |
 | a parameter or response header in a style the OpenAPI style table does not define for its location or value. See below. | `param-unsupported` |
 | a form-style cookie that holds a list or object with `explode: true`. OpenAPI says it writes the wrong delimiter for cookies. `style: cookie` writes it. | `param-unsupported` |
 | nesting the table above does not list | `param-unsupported` |

docs/types.md

@@ -115,7 +115,8 @@ type Device struct {
   a union takes any JSON for it.
 - A parameter or header of such a type needs one that implements `encoding.TextMarshaler` and
   `encoding.TextUnmarshaler`.
-- A union parameter with such a member gets no field, with a warning.
+- A union parameter with such a member gets no field, with a warning, unless its style is
+  `deepObject`.
 
 ## Pointers
 
@@ -489,7 +490,8 @@ A union of strings, numbers and booleans with no shared properties also gets `Ma
 - Text that reads as a JSON number or boolean is tried as one first, then as a string.
 - A union with nothing set has no text: sending it is an error.
 - A query, header or cookie parameter whose union has an object or array variant gets no field,
-  with a warning. So does a list or map of such unions.
+  with a warning. So does a list or map of such unions. A `deepObject` query parameter is the
+  exception: it is written with brackets, `created[gte]=1` or `created=1`.
 
 #### Forms
 

examples/client/params/api.yaml

@@ -30,6 +30,7 @@ paths:
           in: query
           schema: {type: object, properties: {reference: {type: string}, status: {type: array, items: {type: string}}}}
         - {name: id, in: query, schema: {oneOf: [{type: integer}, {type: string}]}}
+        - {name: created, in: query, style: deepObject, schema: {anyOf: [{$ref: '#/components/schemas/Range'}, {type: integer}]}}
         - {name: ids, in: query, allowReserved: true, schema: {type: string}}
         - {name: needed, in: query, required: true, schema: {type: string}}
       responses:
@@ -92,6 +93,11 @@ paths:
             application/json: {schema: {$ref: '#/components/schemas/Echo'}}
 components:
   schemas:
+    Range:
+      type: object
+      properties:
+        gte: {type: integer}
+        lt: {type: integer}
     Point:
       type: object
       properties:

examples/client/params/gen_test.go

@@ -84,6 +84,16 @@ func TestQueryStyles(t *testing.T) {
 			query: &QueryStylesQuery{ID: &QueryStylesQueryID{String: new("a7")}, Needed: "yes"},
 			want:  "id=a7&needed=yes",
 		},
+		{
+			name:  "A deepObject union writes an object variant under brackets",
+			query: &QueryStylesQuery{Created: &QueryStylesQueryCreated{Range: &Range{Gte: new(1), Lt: new(2)}}, Needed: "yes"},
+			want:  "created%5Bgte%5D=1&created%5Blt%5D=2&needed=yes",
+		},
+		{
+			name:  "A deepObject union writes one value under its name",
+			query: &QueryStylesQuery{Created: &QueryStylesQueryCreated{Int: new(5)}, Needed: "yes"},
+			want:  "created=5&needed=yes",
+		},
 		{
 			name:  "A space and a comma inside an item are escaped, reserved characters kept where allowed",
 			query: &QueryStylesQuery{Csv: []string{"a b", "c,d"}, IDs: new("List(1,2)"), Needed: "x y"},

examples/server/beego/params/api.yaml

@@ -26,6 +26,7 @@ paths:
         - {name: flat, in: query, explode: false, schema: {$ref: '#/components/schemas/Point'}}
         - {name: json, in: query, content: {application/json: {schema: {$ref: '#/components/schemas/Point'}}}}
         - {name: id, in: query, schema: {oneOf: [{type: integer}, {type: string}]}}
+        - {name: created, in: query, style: deepObject, schema: {anyOf: [{$ref: '#/components/schemas/Range'}, {type: integer}]}}
         - {name: needed, in: query, required: true, schema: {type: string}}
         - {name: limit, in: query, schema: {type: integer, default: 20}}
       responses:
@@ -77,6 +78,11 @@ paths:
             application/json: {schema: {$ref: '#/components/schemas/Echo'}}
 components:
   schemas:
+    Range:
+      type: object
+      properties:
+        gte: {type: integer}
+        lt: {type: integer}
     Point:
       type: object
       properties:

examples/server/chi/params/api.yaml

@@ -26,6 +26,7 @@ paths:
         - {name: flat, in: query, explode: false, schema: {$ref: '#/components/schemas/Point'}}
         - {name: json, in: query, content: {application/json: {schema: {$ref: '#/components/schemas/Point'}}}}
         - {name: id, in: query, schema: {oneOf: [{type: integer}, {type: string}]}}
+        - {name: created, in: query, style: deepObject, schema: {anyOf: [{$ref: '#/components/schemas/Range'}, {type: integer}]}}
         - {name: needed, in: query, required: true, schema: {type: string}}
         - {name: limit, in: query, schema: {type: integer, default: 20}}
       responses:
@@ -77,6 +78,11 @@ paths:
             application/json: {schema: {$ref: '#/components/schemas/Echo'}}
 components:
   schemas:
+    Range:
+      type: object
+      properties:
+        gte: {type: integer}
+        lt: {type: integer}
     Point:
       type: object
       properties: