feat(project): lock task mutation context

src/test/java/com/lab/labtimesheet/feature/project/service/ProjectServiceIntegrationTest.java

@@ -144,11 +144,14 @@ class ProjectServiceIntegrationTest {
         assertEquals(List.of(), projectPages.listVisible(unrelatedId));
         assertEquals(projectId, projectPages.detail(memberId, projectId).id());
         assertEquals("INTERN", projectPages.authenticatedActor("member-view@example.test").role());
-        var taskContext = projectPages.taskContext(memberId, projectId);
+        var taskContext = projectService.taskMutationContext(memberId, projectId);
         assertEquals(mentorId, taskContext.mentorUserId());
         assertEquals("PLANNED", taskContext.status());
         assertEquals(2, taskContext.activeMembers().size());
         assertEquals(membershipId(projectId, leaderId), taskContext.currentLeaderMembershipId());
+        assertEquals(taskContext, projectPages.taskContext(memberId, projectId));
+        assertThrows(ProjectAccessDeniedException.class,
+                () -> projectService.taskMutationContext(otherMentorId, projectId));
         jdbc.update("""
                 update projects set status = 'ACTIVE', activated_at = ?, updated_at = ? where id = ?
                 """, dbTime(NOW.plusSeconds(30)), dbTime(NOW.plusSeconds(30)), projectId);
@@ -169,7 +172,7 @@ class ProjectServiceIntegrationTest {
         entityManager.clear();
 
         assertEquals(projectId, projectPages.detail(memberId, projectId).id());
-        assertTrue(projectPages.taskContext(memberId, projectId).activeMembers().stream()
+        assertTrue(projectService.taskMutationContext(memberId, projectId).activeMembers().stream()
                 .noneMatch(member -> member.userId() == memberId));
         assertEquals(0, projectPages.dashboardSummary(memberId).activeProjectCount());
         assertEquals(1, projectPages.dashboardSummary(mentorId).distinctActiveMemberCount());

src/test/java/com/lab/labtimesheet/feature/project/service/ProjectTaskMutationContextTest.java

@@ -0,0 +1,59 @@
+package com.lab.labtimesheet.feature.project.service;
+
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.lab.labtimesheet.feature.account.service.AccountService;
+import com.lab.labtimesheet.feature.project.model.dto.ProjectTaskContext;
+import com.lab.labtimesheet.feature.project.model.entity.ProjectEntity;
+import com.lab.labtimesheet.feature.project.repository.ProjectRepository;
+import java.time.Clock;
+import java.time.LocalDate;
+import java.util.List;
+import java.util.Optional;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+class ProjectTaskMutationContextTest {
+
+    @Mock
+    private ProjectRepository projects;
+
+    @Mock
+    private AccountService accounts;
+
+    @Mock
+    private ProjectQueryService queries;
+
+    @Mock
+    private ProjectEntity project;
+
+    @Test
+    void loadsTheProjectForUpdateBeforeBuildingTheTaskMutationContext() {
+        long actorUserId = 20L;
+        long projectId = 30L;
+        var expected = new ProjectTaskContext(
+                projectId,
+                10L,
+                "ACTIVE",
+                LocalDate.of(2026, 8, 15),
+                LocalDate.of(2026, 9, 30),
+                40L,
+                List.of());
+        var service = new ProjectService(projects, accounts, queries, Clock.systemUTC());
+        when(projects.findLockedById(projectId)).thenReturn(Optional.of(project));
+        when(queries.taskContext(actorUserId, project)).thenReturn(expected);
+
+        var actual = service.taskMutationContext(actorUserId, projectId);
+
+        assertSame(expected, actual);
+        verify(projects).findLockedById(projectId);
+        verify(projects, never()).findById(projectId);
+        verify(queries).taskContext(actorUserId, project);
+    }
+}