From 06e0f39b56b796ed2b5f94c0d37899aff410e6c6 Mon Sep 17 00:00:00 2001
From: Runxi Yu <me@runxiyu.org>
Date: Tue, 11 Feb 2025 23:48:21 +0800
Subject: [PATCH] repo_commit: Don't crash when viewing the first commit

---
 handle_repo_commit.go           | 31 +++++++++++++++++++++++--------
 templates/repo_commit.html.tmpl |  4 ++--

diff --git a/handle_repo_commit.go b/handle_repo_commit.go
index d45fd1d5981cdb716fa00c9eae2da6beaa7c1aa4..5f7d495229f182356ea6f7c5a77fdb8316e535b9 100644
--- a/handle_repo_commit.go
+++ b/handle_repo_commit.go
@@ -1,10 +1,12 @@
 package main
 
 import (
+	"errors"
 	"net/http"
 	"strings"
 
 	"github.com/go-git/go-git/v5/plumbing"
+	"github.com/go-git/go-git/v5/plumbing/object"
 	"github.com/go-git/go-git/v5/plumbing/filemode"
 	"github.com/go-git/go-git/v5/plumbing/format/diff"
 	"go.lindenii.runxiyu.org/lindenii-common/misc"
@@ -51,17 +53,30 @@
 	data["commit_object"] = commit_object
 	data["commit_id"] = commit_id_string
 
+	var patch *object.Patch
 	parent_commit_object, err := commit_object.Parent(0)
-	if err != nil {
+	if errors.Is(err, object.ErrParentNotFound) {
+		commit_tree, err := commit_object.Tree()
+		if err != nil {
+			_, _ = w.Write([]byte("Error getting commit tree (for comparing against an empty tree): " + err.Error()))
+			return
+		}
+		patch, err = (&object.Tree{}).Patch(commit_tree)
+		if err != nil {
+			_, _ = w.Write([]byte("Error getting patch of commit: " + err.Error()))
+			return
+		}
+	} else if err != nil {
 		_, _ = w.Write([]byte("Error getting parent commit object: " + err.Error()))
 		return
-	}
-	data["parent_commit_object"] = parent_commit_object
-
-	patch, err := parent_commit_object.Patch(commit_object)
-	if err != nil {
-		_, _ = w.Write([]byte("Error getting patch of commit: " + err.Error()))
-		return
+	} else {
+		data["parent_commit_hash"] = parent_commit_object.Hash.String()
+	
+		patch, err = parent_commit_object.Patch(commit_object)
+		if err != nil {
+			_, _ = w.Write([]byte("Error getting patch of commit: " + err.Error()))
+			return
+		}
 	}
 	data["patch"] = patch
 
diff --git a/templates/repo_commit.html.tmpl b/templates/repo_commit.html.tmpl
index d56888773de32b648b038e342c9d5ec29b731183..13832a8b000cf3bcce30218fd4506cdb065e3f7a 100644
--- a/templates/repo_commit.html.tmpl
+++ b/templates/repo_commit.html.tmpl
@@ -46,14 +46,14 @@ 				</tbody>
 			</table>
 		</div>
 		<div class="padding-wrapper">
-			{{ $parent_commit_object := .parent_commit_object }}
+			{{ $parent_commit_hash := .parent_commit_hash }}
 			{{ $commit_object := .commit_object }}
 			{{ range .file_patches }}
 				<div class="file-patch toggle-on-wrapper">
 					<input type="checkbox" id="toggle-{{ .From.Hash }}{{ .To.Hash }}" class="file-toggle toggle-on-toggle">
 					<label for="toggle-{{ .From.Hash }}{{ .To.Hash }}" class="file-header toggle-on-header">
 						<span>
-							--- a/<a href="../tree/{{ .From.Path }}?commit={{ $parent_commit_object.Hash }}">{{ .From.Path }}</a> {{ .From.Mode }}
+							--- a/<a href="../tree/{{ .From.Path }}?commit={{ $parent_commit_hash }}">{{ .From.Path }}</a> {{ .From.Mode }}
 							<br />
 							+++ b/<a href="../tree/{{ .To.Path }}?commit={{ $commit_object.Hash }}">{{ .To.Path }}</a> {{ .To.Mode }}
 						</span>

-- 
2.48.1