oldgit: Separate some go-git stuff into here

4 files changed, 46 insertions, 38 deletions

diff --git a/git_misc.go b/git_misc.go
index 40247f1..83ee11c 100644
--- a/git_misc.go
+++ b/git_misc.go
@@ -10,7 +10,6 @@ import (
 	"iter"
 
 	"github.com/go-git/go-git/v5"
-	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/object"
 	"github.com/jackc/pgx/v5/pgtype"
 )
@@ -86,34 +85,3 @@ func commitIterSeqErr(commitIter object.CommitIter) (iter.Seq[*object.Commit], *
 		}
 	}, &err
 }
-
-// commitToPatch creates an [object.Patch] from the first parent of a given
-// [object.Commit].
-//
-// TODO: This function should be deprecated as it only diffs with the first
-// parent and does not correctly handle merge commits.
-func commitToPatch(commit *object.Commit) (parentCommitHash plumbing.Hash, patch *object.Patch, err error) {
-	var parentCommit *object.Commit
-	var commitTree *object.Tree
-
-	parentCommit, err = commit.Parent(0)
-	switch {
-	case errors.Is(err, object.ErrParentNotFound):
-		if commitTree, err = commit.Tree(); err != nil {
-			return
-		}
-		if patch, err = nullTree.Patch(commitTree); err != nil {
-			return
-		}
-	case err != nil:
-		return
-	default:
-		parentCommitHash = parentCommit.Hash
-		if patch, err = parentCommit.Patch(commit); err != nil {
-			return
-		}
-	}
-	return
-}
-
-var nullTree object.Tree //nolint:gochecknoglobals
diff --git a/http_handle_repo_commit.go b/http_handle_repo_commit.go
index 196489f..22ee20d 100644
--- a/http_handle_repo_commit.go
+++ b/http_handle_repo_commit.go
@@ -14,6 +14,7 @@ import (
 	"github.com/go-git/go-git/v5/plumbing/format/diff"
 	"github.com/go-git/go-git/v5/plumbing/object"
 	"go.lindenii.runxiyu.org/forge/internal/misc"
+	"go.lindenii.runxiyu.org/forge/internal/oldgit"
 	"go.lindenii.runxiyu.org/forge/internal/web"
 )
 
@@ -52,7 +53,7 @@ func (s *Server) httpHandleRepoCommit(writer http.ResponseWriter, request *http.
 	}
 	if commitIDStrSpecNoSuffix != commitIDStrSpec {
 		var patchStr string
-		if patchStr, err = fmtCommitPatch(commitObj); err != nil {
+		if patchStr, err = oldgit.FmtCommitPatch(commitObj); err != nil {
 			web.ErrorPage500(s.templates, writer, params, "Error formatting patch: "+err.Error())
 			return
 		}
@@ -69,7 +70,7 @@ func (s *Server) httpHandleRepoCommit(writer http.ResponseWriter, request *http.
 	params["commit_object"] = commitObj
 	params["commit_id"] = commitIDStr
 
-	parentCommitHash, patch, err = commitToPatch(commitObj)
+	parentCommitHash, patch, err = oldgit.CommitToPatch(commitObj)
 	if err != nil {
 		web.ErrorPage500(s.templates, writer, params, "Error getting patch from commit: "+err.Error())
 		return
diff --git a/git_format_patch.go b/internal/oldgit/fmtpatch.go
index 5628ce1..79be5d8 100644
--- a/git_format_patch.go
+++ b/internal/oldgit/fmtpatch.go
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 // SPDX-FileCopyrightText: Copyright (c) 2025 Runxi Yu <https://runxiyu.org>
 
-package forge
+package oldgit
 
 import (
 	"bytes"
@@ -12,16 +12,16 @@ import (
 	"github.com/go-git/go-git/v5/plumbing/object"
 )
 
-// fmtCommitPatch formats a commit object as if it was returned by
+// FmtCommitPatch formats a commit object as if it was returned by
 // git-format-patch.
-func fmtCommitPatch(commit *object.Commit) (final string, err error) {
+func FmtCommitPatch(commit *object.Commit) (final string, err error) {
 	var patch *object.Patch
 	var buf bytes.Buffer
 	var author object.Signature
 	var date string
 	var commitTitle, commitDetails string
 
-	if _, patch, err = commitToPatch(commit); err != nil {
+	if _, patch, err = CommitToPatch(commit); err != nil {
 		return "", err
 	}
 
diff --git a/internal/oldgit/patch.go b/internal/oldgit/patch.go
new file mode 100644
index 0000000..329bdfb
--- /dev/null
+++ b/internal/oldgit/patch.go
@@ -0,0 +1,39 @@
+package oldgit
+
+import (
+	"errors"
+
+	"github.com/go-git/go-git/v5/plumbing"
+	"github.com/go-git/go-git/v5/plumbing/object"
+)
+
+// CommitToPatch creates an [object.Patch] from the first parent of a given
+// [object.Commit].
+//
+// TODO: This function should be deprecated as it only diffs with the first
+// parent and does not correctly handle merge commits.
+func CommitToPatch(commit *object.Commit) (parentCommitHash plumbing.Hash, patch *object.Patch, err error) {
+	var parentCommit *object.Commit
+	var commitTree *object.Tree
+
+	parentCommit, err = commit.Parent(0)
+	switch {
+	case errors.Is(err, object.ErrParentNotFound):
+		if commitTree, err = commit.Tree(); err != nil {
+			return
+		}
+		if patch, err = NullTree.Patch(commitTree); err != nil {
+			return
+		}
+	case err != nil:
+		return
+	default:
+		parentCommitHash = parentCommit.Hash
+		if patch, err = parentCommit.Patch(commit); err != nil {
+			return
+		}
+	}
+	return
+}
+
+var NullTree object.Tree //nolint:gochecknoglobals