replace log.Fatal/os.Exit with error returns (#941)

* Use stdlib encoders
* Reduce some duplication
* Remove global pagination state
* Dedupe JSON detail types
* Bump golangci-lint

Reviewed-on: https://gitea.com/gitea/tea/pulls/941
Co-authored-by: techknowlogick <techknowlogick@gitea.com>
Co-committed-by: techknowlogick <techknowlogick@gitea.com>

cmd/detail_json.go

@@ -0,0 +1,93 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cmd
+
+import (
+	"encoding/json"
+	"io"
+	"time"
+
+	"code.gitea.io/sdk/gitea"
+)
+
+type detailLabelData struct {
+	Name        string `json:"name"`
+	Color       string `json:"color"`
+	Description string `json:"description"`
+}
+
+type detailCommentData struct {
+	ID      int64     `json:"id"`
+	Author  string    `json:"author"`
+	Created time.Time `json:"created"`
+	Body    string    `json:"body"`
+}
+
+type detailReviewData struct {
+	ID       int64                 `json:"id"`
+	Reviewer string                `json:"reviewer"`
+	State    gitea.ReviewStateType `json:"state"`
+	Body     string                `json:"body"`
+	Created  time.Time             `json:"created"`
+}
+
+func buildDetailLabels(labels []*gitea.Label) []detailLabelData {
+	labelSlice := make([]detailLabelData, 0, len(labels))
+	for _, label := range labels {
+		labelSlice = append(labelSlice, detailLabelData{
+			Name:        label.Name,
+			Color:       label.Color,
+			Description: label.Description,
+		})
+	}
+	return labelSlice
+}
+
+func buildDetailAssignees(assignees []*gitea.User) []string {
+	assigneeSlice := make([]string, 0, len(assignees))
+	for _, assignee := range assignees {
+		assigneeSlice = append(assigneeSlice, username(assignee))
+	}
+	return assigneeSlice
+}
+
+func buildDetailComments(comments []*gitea.Comment) []detailCommentData {
+	commentSlice := make([]detailCommentData, 0, len(comments))
+	for _, comment := range comments {
+		commentSlice = append(commentSlice, detailCommentData{
+			ID:      comment.ID,
+			Author:  username(comment.Poster),
+			Body:    comment.Body,
+			Created: comment.Created,
+		})
+	}
+	return commentSlice
+}
+
+func buildDetailReviews(reviews []*gitea.PullReview) []detailReviewData {
+	reviewSlice := make([]detailReviewData, 0, len(reviews))
+	for _, review := range reviews {
+		reviewSlice = append(reviewSlice, detailReviewData{
+			ID:       review.ID,
+			Reviewer: username(review.Reviewer),
+			State:    review.State,
+			Body:     review.Body,
+			Created:  review.Submitted,
+		})
+	}
+	return reviewSlice
+}
+
+func username(user *gitea.User) string {
+	if user == nil {
+		return "ghost"
+	}
+	return user.UserName
+}
+
+func writeIndentedJSON(w io.Writer, data any) error {
+	encoder := json.NewEncoder(w)
+	encoder.SetIndent("", "\t")
+	return encoder.Encode(data)
+}