api: deprecate CreateChange using ChangeInfo (use ChangeInput instead)

The API docs refer to the ChangeInput entity for create-change, see
Documentation/rest-api-changes.html#change-input

Rename the existing CreateChange(ChangeInfo) method to
CreateChangeDeprecated and add a new CreateChange(ChangeInput)
implementation. Also added a test that ensures that none of the JSON
payload strings are empty strings (gerrit does not like those).

changes.go

@@ -367,6 +367,15 @@ type AttentionSetInfo struct {
 // the edits to span newlines.
 type DiffIntralineInfo [][2]int
 
+// ChangeInput entity contains information about creating a new change.
+type ChangeInput struct {
+	Project string `json:"project"`
+	Branch  string `json:"branch"`
+	Subject string `json:"subject"`
+	Topic   string `json:"topic,omitempty"`
+	Status  string `json:"status,omitempty"`
+}
+
 // ChangeInfo entity contains information about a change.
 type ChangeInfo struct {
 	ID                     string                      `json:"id"`
@@ -703,15 +712,38 @@ func (s *ChangesService) getCommentInfoMapSliceResponse(u string) (*map[string][
 }
 
 // CreateChange creates a new change.
-// The change info ChangeInfo entity must be provided in the request body.
+//
+// The change input ChangeInput entity must be provided in the request body.
+//
 // Only the following attributes are honored: project, branch, subject, status and topic.
 // The first three attributes are mandatory.
+//
 // Valid values for status are: DRAFT and NEW.
 //
 // As response a ChangeInfo entity is returned that describes the resulting change.
 //
 // Gerrit API docs: https://gerrit-review.googlesource.com/Documentation/rest-api-changes.html#create-change
-func (s *ChangesService) CreateChange(input *ChangeInfo) (*ChangeInfo, *Response, error) {
+func (s *ChangesService) CreateChange(input *ChangeInput) (*ChangeInfo, *Response, error) {
+	u := "changes/"
+
+	req, err := s.client.NewRequest("POST", u, input)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	v := new(ChangeInfo)
+	resp, err := s.client.Do(req, v)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return v, resp, err
+}
+
+// CreateChangeDeprecated creates a new change. (DEPRECATED)
+//
+// Use CreateChange instead.
+func (s *ChangesService) CreateChangeDeprecated(input *ChangeInfo) (*ChangeInfo, *Response, error) {
 	u := "changes/"
 
 	req, err := s.client.NewRequest("POST", u, input)

changes_test.go

@@ -1,6 +1,7 @@
 package gerrit_test
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
@@ -105,6 +106,68 @@ func ExampleChangesService_PublishChangeEdit() {
 	}
 }
 
+func TestChangesService_CreateChange(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		decoder := json.NewDecoder(r.Body)
+		var payload map[string]interface{}
+		if err := decoder.Decode(&payload); err != nil {
+			t.Error(err)
+		}
+
+		jsonStr, err := json.MarshalIndent(payload, "", " ")
+		if err != nil {
+			t.Error(err)
+		}
+		t.Logf("Request payload:\n%s", jsonStr)
+
+		required := func(field string) string {
+			value, ok := payload[field]
+			strVal := value.(string)
+			if !ok {
+				t.Errorf("Missing required field %q", field)
+			}
+			return strVal
+		}
+		project := required("project")
+		branch := required("branch")
+		subject := required("subject")
+
+		for field, generic := range payload {
+			switch value := generic.(type) {
+			case string:
+				if len(value) == 0 {
+					t.Errorf("Empty value for field %q", field)
+				}
+			}
+		}
+
+		if r.URL.Path != "/changes/" {
+			t.Errorf("%s != /changes/", r.URL.Path)
+		}
+		if r.Method != "POST" {
+			t.Errorf("%s != POST", r.Method)
+		}
+		fmt.Fprintf(w, `{ "id": "abc1234", "project": "%s", "branch": "%s", "subject": "%s"}`, project, branch, subject)
+	}))
+	defer ts.Close()
+
+	client, err := gerrit.NewClient(ts.URL, nil)
+	if err != nil {
+		t.Error(err)
+	}
+	info, _, err := client.Changes.CreateChange(&gerrit.ChangeInput{
+		Project: "myProject",
+		Branch:  "main",
+		Subject: "test change",
+	})
+	if err != nil {
+		t.Error(err)
+	}
+	if info.ID != "abc1234" {
+		t.Error("Invalid id")
+	}
+}
+
 func TestChangesService_SubmitChange(t *testing.T) {
 	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.URL.Path != "/changes/123/submit" {