fix(api): keep milestone due date when it is omitted in edit request (#39869)

`PATCH /repos/{owner}/{repo}/milestones/{id}` always overwrote the due
date with `due_on`, so a request that only changed other fields, such as
`{"state": "closed"}`, silently removed it.

The due date is now kept when `due_on` is omitted, and `"due_on": null`
or `"due_on": ""` remove it.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

models/issues/issue_update.go

@@ -529,7 +529,7 @@ func UpdateIssueMentions(ctx context.Context, issueID int64, mentions []*user_mo
 
 // UpdateIssueDeadline updates an issue deadline and adds comments. Setting a deadline to 0 means deleting it.
 func UpdateIssueDeadline(ctx context.Context, issue *Issue, deadlineUnix timeutil.TimeStamp, doer *user_model.User) (err error) {
-	// if the deadline hasn't changed do nothing
+	// if the deadline hasn't changed, do nothing
 	if issue.DeadlineUnix == deadlineUnix {
 		return nil
 	}
@@ -539,11 +539,11 @@ func UpdateIssueDeadline(ctx context.Context, issue *Issue, deadlineUnix timeuti
 		if err = UpdateIssueCols(ctx, &Issue{ID: issue.ID, DeadlineUnix: deadlineUnix}, "deadline_unix"); err != nil {
 			return err
 		}
-
 		// Make the comment
 		if _, err = createDeadlineComment(ctx, doer, issue, deadlineUnix); err != nil {
-			return fmt.Errorf("createRemovedDueDateComment: %w", err)
+			return fmt.Errorf("createDeadlineComment: %w", err)
 		}
+		issue.DeadlineUnix = deadlineUnix
 		return nil
 	})
 }

modules/optional/serialization.go

@@ -4,17 +4,28 @@
 package optional
 
 import (
+	"reflect"
+
 	"gitea.dev/modules/json"
 
 	"go.yaml.in/yaml/v4"
 )
 
+func (o *Option[T]) assignUnmarshalledValue(v *T) {
+	if reflect.TypeFor[T]().Kind() == reflect.Pointer && v == nil {
+		var zero T
+		*o = Some[T](zero)
+	} else {
+		*o = FromPtr(v)
+	}
+}
+
 func (o *Option[T]) UnmarshalJSON(data []byte) error {
 	var v *T
 	if err := json.Unmarshal(data, &v); err != nil {
 		return err
 	}
-	*o = FromPtr(v)
+	o.assignUnmarshalledValue(v)
 	return nil
 }
 
@@ -31,7 +42,7 @@ func (o *Option[T]) UnmarshalYAML(value *yaml.Node) error {
 	if err := value.Decode(&v); err != nil {
 		return err
 	}
-	*o = FromPtr(v)
+	o.assignUnmarshalledValue(v)
 	return nil
 }
 

modules/optional/serialization_test.go

@@ -6,6 +6,7 @@ package optional_test
 import (
 	std_json "encoding/json" //nolint:depguard // for testing purpose
 	"testing"
+	"time"
 
 	"gitea.dev/modules/json"
 	"gitea.dev/modules/optional"
@@ -28,6 +29,14 @@ type testSerializationStruct struct {
 	OptTwoString optional.Option[string] `json:"optional_two_string" yaml:"optional_two_string"`
 }
 
+type testSerializationNullValue struct {
+	OptString optional.Option[string] `json:"opt_null,omitempty" yaml:"opt_null,omitempty"`
+}
+
+type testSerializationNullPointer struct {
+	OptNull optional.Option[*time.Time] `json:"opt_null,omitempty" yaml:"opt_null,omitempty"`
+}
+
 func TestOptionalToJson(t *testing.T) {
 	tests := []struct {
 		name string
@@ -63,6 +72,32 @@ func TestOptionalToJson(t *testing.T) {
 			assert.Equal(t, tc.want, string(b), "std json module returned unexpected")
 		})
 	}
+
+	t.Run("NullValue", func(t *testing.T) {
+		var v1 testSerializationNullValue
+		err := json.Unmarshal([]byte(`{"opt_null":null}`), &v1)
+		assert.NoError(t, err)
+		assert.False(t, v1.OptString.Has())
+	})
+
+	t.Run("NullPointer", func(t *testing.T) {
+		var v1 testSerializationNullPointer
+		err := json.Unmarshal([]byte(`{"opt_null":null}`), &v1)
+		assert.NoError(t, err)
+		assert.True(t, v1.OptNull.Has())
+		assert.Nil(t, v1.OptNull.Value())
+
+		var v2 testSerializationNullPointer
+		err = std_json.Unmarshal([]byte(`{}`), &v2)
+		assert.NoError(t, err)
+		assert.False(t, v2.OptNull.Has())
+
+		var v3 testSerializationNullPointer
+		err = std_json.Unmarshal([]byte(`{"opt_null":"2006-01-02T15:04:05Z"}`), &v3)
+		assert.NoError(t, err)
+		assert.True(t, v3.OptNull.Has())
+		assert.NotNil(t, v3.OptNull.Value())
+	})
 }
 
 func TestOptionalFromJson(t *testing.T) {

modules/structs/issue.go

@@ -10,6 +10,8 @@ import (
 	"strings"
 	"time"
 
+	"gitea.dev/modules/optional"
+
 	"go.yaml.in/yaml/v4"
 )
 
@@ -96,7 +98,7 @@ type CreateIssueOption struct {
 	Assignee  string   `json:"assignee"`
 	Assignees []string `json:"assignees"`
 	// swagger:strfmt date-time
-	Deadline *time.Time `json:"due_date"`
+	Deadline optional.Option[*string] `json:"due_date,omitzero"`
 	// milestone id
 	Milestone int64 `json:"milestone"`
 	// list of label ids
@@ -118,9 +120,10 @@ type EditIssueOption struct {
 	// list of project ids to set (replaces existing projects)
 	Projects *[]int64 `json:"projects"`
 	State    *string  `json:"state"`
+	// Deadline is the updated due date for the issue, use null or empty string to remove the deadline
 	// swagger:strfmt date-time
-	Deadline       *time.Time `json:"due_date"`
-	RemoveDeadline *bool      `json:"unset_due_date"`
+	Deadline       optional.Option[*string] `json:"due_date,omitzero"`
+	RemoveDeadline *bool                    `json:"unset_due_date"`
 	// The current version of the issue content to detect conflicts during editing
 	ContentVersion *int `json:"content_version"`
 }
@@ -130,10 +133,11 @@ type IssueAssigneesOption struct {
 	Assignees []string `json:"assignees"`
 }
 
-// EditDeadlineOption options for creating a deadline
+// EditDeadlineOption options for editing a deadline
 type EditDeadlineOption struct {
-	// required:true
-	Deadline *time.Time `json:"due_date"`
+	// Deadline is the updated due date for the issue or pull request, use null or empty string to remove the deadline
+	// swagger:strfmt date-time
+	Deadline optional.Option[*string] `json:"due_date,omitzero"`
 }
 
 // IssueDeadline represents an issue deadline

modules/structs/issue_milestone.go

@@ -5,9 +5,11 @@ package structs
 
 import (
 	"time"
+
+	"gitea.dev/modules/optional"
 )
 
-// Milestone milestone is a collection of issues on one repository
+// Milestone is a collection of issues on one repository
 type Milestone struct {
 	// ID is the unique identifier for the milestone
 	ID int64 `json:"id"`
@@ -39,7 +41,7 @@ type CreateMilestoneOption struct {
 	Description string `json:"description"`
 	// swagger:strfmt date-time
 	// Deadline is the due date for the milestone
-	Deadline *time.Time `json:"due_on"`
+	Deadline optional.Option[*string] `json:"due_on,omitzero"`
 	// enum: ["open","closed"]
 	// State indicates the initial state of the milestone
 	State string `json:"state"`
@@ -54,6 +56,7 @@ type EditMilestoneOption struct {
 	// State indicates the updated state of the milestone
 	// enum: ["open","closed"]
 	State *string `json:"state"`
-	// Deadline is the updated due date for the milestone
-	Deadline *time.Time `json:"due_on"`
+	// Deadline is the due date for the milestone, use null or empty string to remove the deadline
+	// swagger:strfmt date-time
+	Deadline optional.Option[*string] `json:"due_on,omitzero"`
 }

modules/structs/pull.go

@@ -5,6 +5,8 @@ package structs
 
 import (
 	"time"
+
+	"gitea.dev/modules/optional"
 )
 
 // PullRequest represents a pull request
@@ -137,7 +139,7 @@ type CreatePullRequestOption struct {
 	// The list of label IDs to assign to the pull request
 	Labels []int64 `json:"labels"`
 	// swagger:strfmt date-time
-	Deadline *time.Time `json:"due_date"`
+	Deadline optional.Option[*string] `json:"due_date,omitzero"`
 	// The list of reviewer usernames
 	Reviewers []string `json:"reviewers"`
 	// The list of team reviewer names
@@ -164,8 +166,9 @@ type EditPullRequestOption struct {
 	Labels []int64 `json:"labels"`
 	// The new state for the pull request
 	State *string `json:"state"`
+	// Deadline is the updated due date for the pull request, use null or empty string to remove the deadline
 	// swagger:strfmt date-time
-	Deadline *time.Time `json:"due_date"`
+	Deadline optional.Option[*string] `json:"due_date,omitzero"`
 	// Whether to remove the current deadline
 	RemoveDeadline *bool `json:"unset_due_date"`
 	// Whether to allow maintainer edits

routers/api/v1/repo/issue.go

@@ -10,7 +10,6 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
-	"time"
 
 	"gitea.dev/models/db"
 	issues_model "gitea.dev/models/issues"
@@ -577,9 +576,12 @@ func CreateIssue(ctx *context.APIContext) {
 	}
 
 	assigneeIDs := make([]int64, 0)
-	var err error
 	if ctx.Repo.Permission.CanWrite(unit.TypeIssues) {
-		issue.DeadlineUnix = common.ParseAPIDeadlineToEndOfDay(form.Deadline)
+		_, err := common.ApplyAPIDeadlineTimestamp(&issue.DeadlineUnix, form.Deadline, nil)
+		if err != nil {
+			ctx.APIErrorAuto(err)
+			return
+		}
 		issue.MilestoneID = form.Milestone
 		assigneeIDs, err = issues_model.MakeIDsFromAPIAssigneesToAdd(ctx, form.Assignee, form.Assignees)
 		if err != nil {
@@ -637,6 +639,7 @@ func CreateIssue(ctx *context.APIContext) {
 	}
 
 	// Refetch from database to assign some automatic values
+	var err error
 	issue, err = issues_model.GetIssueByID(ctx, issue.ID)
 	if err != nil {
 		ctx.APIErrorInternal(err)
@@ -890,22 +893,20 @@ func DeleteIssue(ctx *context.APIContext) {
 	ctx.Status(http.StatusNoContent)
 }
 
-func editIssueDeadline(ctx *context.APIContext, issue *issues_model.Issue, deadline *time.Time, removeDeadline *bool) bool {
-	if deadline == nil && removeDeadline == nil {
+func editIssueDeadline(ctx *context.APIContext, issue *issues_model.Issue, deadline optional.Option[*string], removeDeadline *bool) bool {
+	newDeadlineUnix := issue.DeadlineUnix
+	changed, err := common.ApplyAPIDeadlineTimestamp(&newDeadlineUnix, deadline, removeDeadline)
+	if err != nil {
+		ctx.APIErrorAuto(err)
+		return false
+	}
+	if !changed {
 		return true
 	}
-	if removeDeadline != nil && *removeDeadline {
-		deadline = nil
-	} else if deadline == nil {
-		ctx.APIError(http.StatusBadRequest, "The due_date cannot be empty")
+	if err := issues_model.UpdateIssueDeadline(ctx, issue, newDeadlineUnix, ctx.Doer); err != nil {
+		ctx.APIErrorAuto(err)
 		return false
 	}
-	deadlineUnix := common.ParseAPIDeadlineToEndOfDay(deadline)
-	if err := issues_model.UpdateIssueDeadline(ctx, issue, deadlineUnix, ctx.Doer); err != nil {
-		ctx.APIErrorInternal(err)
-		return false
-	}
-	issue.DeadlineUnix = deadlineUnix
 	return true
 }
 
@@ -962,13 +963,20 @@ func UpdateIssueDeadline(ctx *context.APIContext) {
 		return
 	}
 
-	deadlineUnix := common.ParseAPIDeadlineToEndOfDay(form.Deadline)
-	if err := issues_model.UpdateIssueDeadline(ctx, issue, deadlineUnix, ctx.Doer); err != nil {
-		ctx.APIErrorInternal(err)
+	newDeadlineUnix := issue.DeadlineUnix
+	changed, err := common.ApplyAPIDeadlineTimestamp(&newDeadlineUnix, form.Deadline, nil)
+	if err != nil {
+		ctx.APIErrorAuto(err)
 		return
 	}
-
-	ctx.JSON(http.StatusCreated, api.IssueDeadline{Deadline: deadlineUnix.AsTimePtr()})
+	if changed {
+		if err := issues_model.UpdateIssueDeadline(ctx, issue, newDeadlineUnix, ctx.Doer); err != nil {
+			ctx.APIErrorAuto(err)
+			return
+		}
+	}
+	// StatusCreated is the copied & pasted garbage
+	ctx.JSON(http.StatusCreated, api.IssueDeadline{Deadline: issue.DeadlineUnix.AsTimePtr()})
 }
 
 func closeOrReopenIssue(ctx *context.APIContext, issue *issues_model.Issue, state api.StateType) {

routers/api/v1/repo/milestone.go

@@ -150,12 +150,15 @@ func CreateMilestone(ctx *context.APIContext) {
 	form := web.GetForm[*api.CreateMilestoneOption](ctx)
 
 	milestone := &issues_model.Milestone{
-		RepoID:       ctx.Repo.Repository.ID,
-		Name:         form.Title,
-		Content:      form.Description,
-		DeadlineUnix: common.ParseAPIDeadlineToEndOfDay(form.Deadline),
+		RepoID:  ctx.Repo.Repository.ID,
+		Name:    form.Title,
+		Content: form.Description,
+	}
+	_, err := common.ApplyAPIDeadlineTimestamp(&milestone.DeadlineUnix, form.Deadline, nil)
+	if err != nil {
+		ctx.APIErrorAuto(err)
+		return
 	}
-
 	if form.State == "closed" {
 		milestone.IsClosed = true
 		milestone.ClosedDateUnix = timeutil.TimeStampNow()
@@ -204,7 +207,7 @@ func EditMilestone(ctx *context.APIContext) {
 	//     "$ref": "#/responses/notFound"
 	form := web.GetForm[*api.EditMilestoneOption](ctx)
 	milestone := getMilestoneByIDOrName(ctx)
-	if ctx.Written() {
+	if milestone == nil {
 		return
 	}
 
@@ -214,7 +217,10 @@ func EditMilestone(ctx *context.APIContext) {
 	if form.Description != nil {
 		milestone.Content = *form.Description
 	}
-	milestone.DeadlineUnix = common.ParseAPIDeadlineToEndOfDay(form.Deadline)
+	if _, err := common.ApplyAPIDeadlineTimestamp(&milestone.DeadlineUnix, form.Deadline, nil); err != nil {
+		ctx.APIErrorAuto(err)
+		return
+	}
 
 	oldIsClosed := milestone.IsClosed
 	if form.State != nil {

routers/api/v1/repo/pull.go

@@ -496,15 +496,20 @@ func CreatePullRequest(ctx *context.APIContext) {
 	}
 
 	prIssue := &issues_model.Issue{
-		RepoID:       repo.ID,
-		Title:        form.Title,
-		PosterID:     ctx.Doer.ID,
-		Poster:       ctx.Doer,
-		MilestoneID:  milestoneID,
-		IsPull:       true,
-		Content:      form.Body,
-		DeadlineUnix: common.ParseAPIDeadlineToEndOfDay(form.Deadline),
+		RepoID:      repo.ID,
+		Title:       form.Title,
+		PosterID:    ctx.Doer.ID,
+		Poster:      ctx.Doer,
+		MilestoneID: milestoneID,
+		IsPull:      true,
+		Content:     form.Body,
 	}
+	_, err = common.ApplyAPIDeadlineTimestamp(&prIssue.DeadlineUnix, form.Deadline, nil)
+	if err != nil {
+		ctx.APIErrorAuto(err)
+		return
+	}
+
 	pr := &issues_model.PullRequest{
 		HeadRepoID: compareResult.HeadRepo.ID,
 		BaseRepoID: repo.ID,

routers/common/deadline.go

@@ -6,8 +6,10 @@ package common
 import (
 	"time"
 
+	"gitea.dev/modules/optional"
 	"gitea.dev/modules/setting"
 	"gitea.dev/modules/timeutil"
+	"gitea.dev/modules/util"
 )
 
 func ParseDeadlineDateToEndOfDay(date string) (timeutil.TimeStamp, error) {
@@ -22,9 +24,33 @@ func ParseDeadlineDateToEndOfDay(date string) (timeutil.TimeStamp, error) {
 	return timeutil.TimeStamp(deadline.Unix()), nil
 }
 
-func ParseAPIDeadlineToEndOfDay(t *time.Time) timeutil.TimeStamp {
-	if t == nil || t.IsZero() || t.Unix() == 0 {
-		return 0
+func ApplyAPIDeadlineTimestamp(field *timeutil.TimeStamp, input optional.Option[*string], remove *bool) (changed bool, err error) {
+	old := *field
+	if remove != nil && *remove || input.Has() && (input.Value() == nil || *input.Value() == "") {
+		*field = 0
+		return old != *field, nil
 	}
-	return timeutil.TimeStamp(time.Date(t.Year(), t.Month(), t.Day(), 23, 59, 59, 0, setting.DefaultUILocation).Unix())
+
+	if !input.Has() {
+		return false, nil
+	}
+	inputValue := *input.Value()
+
+	formats := []string{
+		"2006-01-02",
+		"2006-01-02 15:04:05",
+		time.RFC3339,
+	}
+	for _, format := range formats {
+		t, err := time.ParseInLocation(format, inputValue, setting.DefaultUILocation)
+		if err == nil {
+			ts := time.Date(t.Year(), t.Month(), t.Day(), 23, 59, 59, 0, setting.DefaultUILocation).Unix()
+			if ts < 86400*2 {
+				ts = 0 // tolerate timezone difference between server and client
+			}
+			*field = timeutil.TimeStamp(ts)
+			return old != *field, nil
+		}
+	}
+	return false, util.NewInvalidArgumentErrorf("invalid date format: %s", inputValue)
 }

templates/swagger/v1-openapi3.generated.json

@@ -5562,17 +5562,15 @@
         "x-go-package": "gitea.dev/modules/structs"
       },
       "EditDeadlineOption": {
-        "description": "EditDeadlineOption options for creating a deadline",
+        "description": "EditDeadlineOption options for editing a deadline",
         "properties": {
           "due_date": {
+            "description": "Deadline is the updated due date for the issue or pull request, use null or empty string to remove the deadline",
             "format": "date-time",
             "type": "string",
             "x-go-name": "Deadline"
           }
         },
-        "required": [
-          "due_date"
-        ],
         "type": "object",
         "x-go-package": "gitea.dev/modules/structs"
       },
@@ -5673,6 +5671,7 @@
             "x-go-name": "ContentVersion"
           },
           "due_date": {
+            "description": "Deadline is the updated due date for the issue, use null or empty string to remove the deadline",
             "format": "date-time",
             "type": "string",
             "x-go-name": "Deadline"
@@ -5752,7 +5751,7 @@
             "x-go-name": "Description"
           },
           "due_on": {
-            "description": "Deadline is the updated due date for the milestone",
+            "description": "Deadline is the due date for the milestone, use null or empty string to remove the deadline",
             "format": "date-time",
             "type": "string",
             "x-go-name": "Deadline"
@@ -5902,6 +5901,7 @@
             "x-go-name": "ContentVersion"
           },
           "due_date": {
+            "description": "Deadline is the updated due date for the pull request, use null or empty string to remove the deadline",
             "format": "date-time",
             "type": "string",
             "x-go-name": "Deadline"
@@ -7948,7 +7948,7 @@
         "x-go-package": "gitea.dev/modules/structs"
       },
       "Milestone": {
-        "description": "Milestone milestone is a collection of issues on one repository",
+        "description": "Milestone is a collection of issues on one repository",
         "properties": {
           "closed_at": {
             "format": "date-time",

templates/swagger/v1-swagger.generated.json

@@ -28658,13 +28658,11 @@
       "x-go-package": "gitea.dev/modules/structs"
     },
     "EditDeadlineOption": {
-      "description": "EditDeadlineOption options for creating a deadline",
+      "description": "EditDeadlineOption options for editing a deadline",
       "type": "object",
-      "required": [
-        "due_date"
-      ],
       "properties": {
         "due_date": {
+          "description": "Deadline is the updated due date for the issue or pull request, use null or empty string to remove the deadline",
           "type": "string",
           "format": "date-time",
           "x-go-name": "Deadline"
@@ -28769,6 +28767,7 @@
           "x-go-name": "ContentVersion"
         },
         "due_date": {
+          "description": "Deadline is the updated due date for the issue, use null or empty string to remove the deadline",
           "type": "string",
           "format": "date-time",
           "x-go-name": "Deadline"
@@ -28848,7 +28847,7 @@
           "x-go-name": "Description"
         },
         "due_on": {
-          "description": "Deadline is the updated due date for the milestone",
+          "description": "Deadline is the due date for the milestone, use null or empty string to remove the deadline",
           "type": "string",
           "format": "date-time",
           "x-go-name": "Deadline"
@@ -29008,6 +29007,7 @@
           "x-go-name": "ContentVersion"
         },
         "due_date": {
+          "description": "Deadline is the updated due date for the pull request, use null or empty string to remove the deadline",
           "type": "string",
           "format": "date-time",
           "x-go-name": "Deadline"
@@ -31055,7 +31055,7 @@
       "x-go-package": "gitea.dev/modules/structs"
     },
     "Milestone": {
-      "description": "Milestone milestone is a collection of issues on one repository",
+      "description": "Milestone is a collection of issues on one repository",
       "type": "object",
       "properties": {
         "closed_at": {

tests/integration/api_issue_milestone_test.go

@@ -41,6 +41,7 @@ func TestAPIIssuesMilestone(t *testing.T) {
 	resp := MakeRequest(t, req, http.StatusOK)
 	apiMilestone := DecodeJSON(t, resp, &structs.Milestone{})
 	assert.EqualValues(t, "closed", apiMilestone.State)
+	assert.NotNil(t, apiMilestone.Deadline, "an omitted due_on keeps the due date")
 
 	req = NewRequest(t, "GET", urlStr).
 		AddTokenAuth(token)
@@ -48,6 +49,10 @@ func TestAPIIssuesMilestone(t *testing.T) {
 	apiMilestone2 := DecodeJSON(t, resp, &structs.Milestone{})
 	assert.EqualValues(t, "closed", apiMilestone2.State)
 
+	req = NewRequestWithJSON(t, "PATCH", urlStr, map[string]any{"due_on": ""}).AddTokenAuth(token)
+	resp = MakeRequest(t, req, http.StatusOK)
+	assert.Nil(t, DecodeJSON(t, resp, &structs.Milestone{}).Deadline)
+
 	req = NewRequestWithJSON(t, "POST", fmt.Sprintf("/api/v1/repos/%s/%s/milestones", owner.Name, repo.Name), structs.CreateMilestoneOption{
 		Title:       "wow",
 		Description: "closed one",

tests/integration/api_issue_test.go

@@ -18,6 +18,7 @@ import (
 	repo_model "gitea.dev/models/repo"
 	"gitea.dev/models/unittest"
 	user_model "gitea.dev/models/user"
+	"gitea.dev/modules/optional"
 	"gitea.dev/modules/setting"
 	api "gitea.dev/modules/structs"
 	"gitea.dev/modules/test"
@@ -126,7 +127,7 @@ func testAPICreateIssue(t *testing.T) {
 		Body:     body,
 		Title:    title,
 		Assignee: owner.Name,
-		Deadline: new(time.Date(2026, 5, 11, 12, 0, 0, 0, time.FixedZone("", -10*3600))),
+		Deadline: optional.Some(new("2026-05-11T12:00:00-10:00")),
 	}).AddTokenAuth(token)
 	resp := MakeRequest(t, req, http.StatusCreated)
 	apiIssue := DecodeJSON(t, resp, &api.Issue{})

tests/integration/api_pull_test.go

@@ -20,6 +20,7 @@ import (
 	unit_model "gitea.dev/models/unit"
 	"gitea.dev/models/unittest"
 	user_model "gitea.dev/models/user"
+	"gitea.dev/modules/optional"
 	"gitea.dev/modules/setting"
 	api "gitea.dev/modules/structs"
 	"gitea.dev/modules/util"
@@ -491,7 +492,7 @@ func TestAPIEditPull(t *testing.T) {
 		Head:     "develop",
 		Base:     "master",
 		Title:    title,
-		Deadline: new(time.Date(2026, 5, 11, 12, 0, 0, 0, time.FixedZone("", -10*3600))),
+		Deadline: optional.Some(new("2026-05-11T12:00:00-10:00")),
 	}).AddTokenAuth(token)
 	resp := MakeRequest(t, req, http.StatusCreated)
 	apiPull := DecodeJSON(t, resp, &api.PullRequest{})
@@ -521,10 +522,20 @@ func TestAPIEditPull(t *testing.T) {
 	}).AddTokenAuth(token)
 	MakeRequest(t, req, http.StatusNotFound)
 
-	req = NewRequestWithJSON(t, http.MethodPatch, fmt.Sprintf("/api/v1/repos/%s/%s/pulls/%d", owner10.Name, repo10.Name, pull.Index), &api.EditPullRequestOption{
-		RemoveDeadline: new(false),
-	}).AddTokenAuth(token)
-	MakeRequest(t, req, http.StatusBadRequest)
+	req = NewRequestWithJSON(t, http.MethodPatch, fmt.Sprintf("/api/v1/repos/%s/%s/pulls/%d", owner10.Name, repo10.Name, pull.Index), map[string]any{"due_date": "2000-01-02"}).AddTokenAuth(token)
+	MakeRequest(t, req, http.StatusCreated)
+	issue := unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: pull.IssueID})
+	assert.NotZero(t, issue.DeadlineUnix)
+
+	req = NewRequestWithJSON(t, http.MethodPatch, fmt.Sprintf("/api/v1/repos/%s/%s/pulls/%d", owner10.Name, repo10.Name, pull.Index), map[string]any{}).AddTokenAuth(token)
+	MakeRequest(t, req, http.StatusCreated)
+	issue = unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: pull.IssueID})
+	assert.NotZero(t, issue.DeadlineUnix)
+
+	req = NewRequestWithJSON(t, http.MethodPatch, fmt.Sprintf("/api/v1/repos/%s/%s/pulls/%d", owner10.Name, repo10.Name, pull.Index), map[string]any{"due_date": nil}).AddTokenAuth(token)
+	MakeRequest(t, req, http.StatusCreated)
+	issue = unittest.AssertExistsAndLoadBean(t, &issues_model.Issue{ID: pull.IssueID})
+	assert.Zero(t, issue.DeadlineUnix)
 
 	t.Run("PullContentVersion", func(t *testing.T) {
 		testAPIPullContentVersion(t, pull.ID)