From 6a840970944957f5b500c74098224b243ee2e523 Mon Sep 17 00:00:00 2001
From: Seongmin Lee <boltlessengineer@proton.me>
Date: Sun, 24 Aug 2025 16:15:09 +0900
Subject: [PATCH] knotserver: set default git committer user via config
Change-Id: skprtmnmwuqnqxzrpzsomqsntyurzpzp

Introducing `KNOT_GIT_USER_NAME` and `KNOT_GIT_USER_EMAIL` environment
variables.

This will prevent silently inheritting global gitconfig's user

Signed-off-by: Seongmin Lee <boltlessengineer@proton.me>
---
 knotserver/config/config.go |  7 +++++++
 knotserver/git/git.go       |  4 ++++
 knotserver/git/merge.go     | 37 ++++++++++++++++++++++---------------
 knotserver/routes.go        | 10 ++++++----
 4 files changed, 39 insertions(+), 19 deletions(-)

diff --git a/knotserver/config/config.go b/knotserver/config/config.go
index a98137b..c564754 100644
--- a/knotserver/config/config.go
+++ b/knotserver/config/config.go
@@ -27,6 +27,12 @@ type Server struct {
 	Dev bool `env:"DEV, default=false"`
 }
 
+type Git struct {
+	// user name & email used as committer
+	UserName     string `env:"USER_NAME, default=Tangled"`
+	UserEmail    string `env:"USER_EMAIL, default=noreply@tangled.sh"`
+}
+
 func (s Server) Did() syntax.DID {
 	return syntax.DID(fmt.Sprintf("did:web:%s", s.Hostname))
 }
@@ -34,6 +40,7 @@ func (s Server) Did() syntax.DID {
 type Config struct {
 	Repo            Repo   `env:",prefix=KNOT_REPO_"`
 	Server          Server `env:",prefix=KNOT_SERVER_"`
+	Git             Git    `env:",prefix=KNOT_GIT_"`
 	AppViewEndpoint string `env:"APPVIEW_ENDPOINT, default=https://tangled.sh"`
 }
 
diff --git a/knotserver/git/git.go b/knotserver/git/git.go
index a5fc5ef..2b6fedc 100644
--- a/knotserver/git/git.go
+++ b/knotserver/git/git.go
@@ -109,6 +109,10 @@ func Open(path string, ref string) (*GitRepo, error) {
 		}
 		g.h = *hash
 	}
+	_, err = g.runGitCmd("config", "user.name", "<name>", "user.email", "<email>")
+	if err != nil {
+		return nil, err
+	}
 	return &g, nil
 }
 
diff --git a/knotserver/git/merge.go b/knotserver/git/merge.go
index 3c9d182..09c2497 100644
--- a/knotserver/git/merge.go
+++ b/knotserver/git/merge.go
@@ -85,11 +85,13 @@ type ConflictInfo struct {
 
 // MergeOptions specifies the configuration for a merge operation
 type MergeOptions struct {
-	CommitMessage string
-	CommitBody    string
-	AuthorName    string
-	AuthorEmail   string
-	FormatPatch   bool
+	CommitMessage  string
+	CommitBody     string
+	AuthorName     string
+	AuthorEmail    string
+	CommitterName  string
+	CommitterEmail string
+	FormatPatch    bool
 }
 
 func (e ErrMerge) Error() string {
@@ -164,7 +166,19 @@ func (g *GitRepo) applyPatch(tmpDir, patchFile string, opts MergeOptions) error
 	var stderr bytes.Buffer
 	var cmd *exec.Cmd
 
-	exec.Command("git", "-C", tmpDir, "config", "advice.mergeConflict", "false").Run()
+	// configure default git user before merge
+	exec.Command(
+		"git",
+		"-C",
+		tmpDir,
+		"config",
+		"user.name",
+		opts.CommitterName,
+		"user.email",
+		opts.CommitterEmail,
+		"advice.mergeConflict",
+		"false",
+	).Run()
 
 	// if patch is a format-patch, apply using 'git am'
 	if opts.FormatPatch {
@@ -188,17 +202,10 @@ func (g *GitRepo) applyPatch(tmpDir, patchFile string, opts MergeOptions) error
 		authorName := opts.AuthorName
 		authorEmail := opts.AuthorEmail
 
-		if authorEmail == "" {
-			authorEmail = "noreply@tangled.sh"
-		}
-
-		if authorName == "" {
-			authorName = "Tangled"
-		}
-
-		if authorName != "" {
+		if authorName != "" && authorEmail != "" {
 			commitArgs = append(commitArgs, "--author", fmt.Sprintf("%s <%s>", authorName, authorEmail))
 		}
+		// else, will default to knot's global user.name & user.email configured via `KNOT_GIT_USER_*` env variables
 
 		commitArgs = append(commitArgs, "-m", opts.CommitMessage)
 
diff --git a/knotserver/routes.go b/knotserver/routes.go
index e2ddeb4..d42ca87 100644
--- a/knotserver/routes.go
+++ b/knotserver/routes.go
@@ -986,10 +986,12 @@ func (h *Handle) Merge(w http.ResponseWriter, r *http.Request) {
 	}
 
 	mo := git.MergeOptions{
-		AuthorName:    data.AuthorName,
-		AuthorEmail:   data.AuthorEmail,
-		CommitBody:    data.CommitBody,
-		CommitMessage: data.CommitMessage,
+		AuthorName:     data.AuthorName,
+		AuthorEmail:    data.AuthorEmail,
+		CommitterName:  h.c.Git.UserName,
+		CommitterEmail: h.c.Git.UserEmail,
+		CommitBody:     data.CommitBody,
+		CommitMessage:  data.CommitMessage,
 		FormatPatch:   patchutil.IsFormatPatch(patch),
 	}
 
-- 
2.43.0