merge: resolve conflicts with main (workdir reuse)

Main added execenv.Reuse() for workdir reuse across tasks on the same
issue. Our branch removed Type/BranchName/gitRoot from Environment
(repos are now checked out on demand). Resolution: keep Reuse() but
simplify it to work with the new Environment struct (no workspace type
tracking). Keep the "reused" log field from main, drop removed fields.

server/internal/daemon/daemon.go

@@ -624,26 +624,33 @@ func (d *Daemon) runTask(ctx context.Context, task Task, provider string) (TaskR
 		AgentSkills:       convertSkillsForEnv(skills),
 		Repos:             convertReposForEnv(task.Repos),
 	}
-	env, err := execenv.Prepare(execenv.PrepareParams{
-		WorkspacesRoot: d.cfg.WorkspacesRoot,
-		TaskID:         task.ID,
-		AgentName:      agentName,
-		Provider:       provider,
-		Task:           taskCtx,
-	}, d.logger)
-	if err != nil {
-		return TaskResult{}, fmt.Errorf("prepare execution environment: %w", err)
+
+	// Try to reuse the workdir from a previous task on the same (agent, issue) pair.
+	var env *execenv.Environment
+	if task.PriorWorkDir != "" {
+		env = execenv.Reuse(task.PriorWorkDir, provider, taskCtx, d.logger)
+	}
+	if env == nil {
+		var err error
+		env, err = execenv.Prepare(execenv.PrepareParams{
+			WorkspacesRoot: d.cfg.WorkspacesRoot,
+			TaskID:         task.ID,
+			AgentName:      agentName,
+			Provider:       provider,
+			Task:           taskCtx,
+		}, d.logger)
+		if err != nil {
+			return TaskResult{}, fmt.Errorf("prepare execution environment: %w", err)
+		}
 	}
 
 	// Inject runtime-specific config (meta skill) so the agent discovers .agent_context/.
 	if err := execenv.InjectRuntimeConfig(env.WorkDir, provider, taskCtx); err != nil {
 		d.logger.Warn("execenv: inject runtime config failed (non-fatal)", "error", err)
 	}
-	defer func() {
-		if cleanupErr := env.Cleanup(!d.cfg.KeepEnvAfterTask); cleanupErr != nil {
-			d.logger.Warn("cleanup env failed", "task_id", task.ID, "error", cleanupErr)
-		}
-	}()
+	// NOTE: No cleanup — workdir is preserved for reuse by future tasks on
+	// the same (agent, issue) pair. The work_dir path is stored in DB on
+	// task completion and passed back via PriorWorkDir on the next claim.
 
 	prompt := BuildPrompt(task)
 
@@ -671,7 +678,7 @@ func (d *Daemon) runTask(ctx context.Context, task Task, provider string) (TaskR
 		return TaskResult{}, fmt.Errorf("create agent backend: %w", err)
 	}
 
-	d.logger.Info("starting agent", "provider", provider, "task_id", task.ID, "workdir", env.WorkDir, "model", entry.Model, "timeout", d.cfg.AgentTimeout.String(), "resume_session", task.PriorSessionID)
+	d.logger.Info("starting agent", "provider", provider, "task_id", task.ID, "workdir", env.WorkDir, "reused", task.PriorWorkDir != "" && env.WorkDir == task.PriorWorkDir, "model", entry.Model, "timeout", d.cfg.AgentTimeout.String(), "resume_session", task.PriorSessionID)
 
 	session, err := backend.Execute(ctx, prompt, agent.ExecOptions{
 		Cwd:             env.WorkDir,

server/internal/daemon/execenv/execenv.go

@@ -116,6 +116,28 @@ func Prepare(params PrepareParams, logger *slog.Logger) (*Environment, error) {
 	return env, nil
 }
 
+// Reuse wraps an existing workdir into an Environment and refreshes context files.
+// Returns nil if the workdir does not exist (caller should fall back to Prepare).
+func Reuse(workDir, provider string, task TaskContextForEnv, logger *slog.Logger) *Environment {
+	if _, err := os.Stat(workDir); err != nil {
+		return nil
+	}
+
+	env := &Environment{
+		RootDir: filepath.Dir(workDir),
+		WorkDir: workDir,
+		logger:  logger,
+	}
+
+	// Refresh context files (issue_context.md, skills).
+	if err := writeContextFiles(workDir, provider, task); err != nil {
+		logger.Warn("execenv: refresh context files failed", "error", err)
+	}
+
+	logger.Info("execenv: reusing env", "workdir", workDir)
+	return env
+}
+
 // Cleanup tears down the execution environment.
 // If removeAll is true, the entire env root is deleted. Otherwise, workdir is
 // removed but output/ and logs/ are preserved for debugging.

server/internal/daemon/types.go

@@ -30,6 +30,7 @@ type Task struct {
 	Agent          *AgentData `json:"agent,omitempty"`
 	Repos          []RepoData `json:"repos,omitempty"`
 	PriorSessionID string     `json:"prior_session_id,omitempty"` // Claude session ID from a previous task on this issue
+	PriorWorkDir   string     `json:"prior_work_dir,omitempty"`   // work_dir from a previous task on this issue
 }
 
 // AgentData holds agent details returned by the claim endpoint.

server/internal/handler/agent.go

@@ -104,6 +104,7 @@ type AgentTaskResponse struct {
 	Repos          []RepoData     `json:"repos,omitempty"`
 	CreatedAt      string         `json:"created_at"`
 	PriorSessionID string         `json:"prior_session_id,omitempty"` // session ID from a previous task on same issue
+	PriorWorkDir   string         `json:"prior_work_dir,omitempty"`   // work_dir from a previous task on same issue
 }
 
 // TaskAgentData holds agent info included in claim responses so the daemon

server/internal/handler/daemon.go

@@ -244,6 +244,9 @@ func (h *Handler) ClaimTaskByRuntime(w http.ResponseWriter, r *http.Request) {
 		IssueID: task.IssueID,
 	}); err == nil && prior.SessionID.Valid {
 		resp.PriorSessionID = prior.SessionID.String
+		if prior.WorkDir.Valid {
+			resp.PriorWorkDir = prior.WorkDir.String
+		}
 	}
 
 	slog.Info("task claimed by runtime", "task_id", uuidToString(task.ID), "runtime_id", runtimeID, "agent_id", uuidToString(task.AgentID), "prior_session", resp.PriorSessionID)