From 9d08dc994d51298e2d8e75d8ed4ee477312ec53a Mon Sep 17 00:00:00 2001
From: Runxi Yu
Date: Sat, 7 Mar 2026 15:08:14 +0800
Subject: ref/refname: Add refname validation

---
 ref/refname/update.go | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 ref/refname/update.go

(limited to 'ref/refname/update.go')

diff --git a/ref/refname/update.go b/ref/refname/update.go
new file mode 100644
index 00000000..92830f1a
--- /dev/null
+++ b/ref/refname/update.go
@@ -0,0 +1,56 @@
+package refname
+
+import "strings"
+
+// ValidateUpdateName checks whether name is valid for one direct ref update.
+//
+// See transaction_refname_valid();
+// updates with a new OID use check_refname_format(..., ALLOW_ONELEVEL),
+// while delete/verify style operations use refname_is_safe().
+func ValidateUpdateName(name string, hasNewValue bool) error {
+	if IsPseudo(name) {
+		return &NameError{Name: name, Reason: "pseudoref updates are not allowed"}
+	}
+
+	if hasNewValue {
+		return Validate(name, Options{AllowOneLevel: true})
+	}
+
+	if !IsSafe(name) {
+		return &NameError{Name: name, Reason: "unsafe refname for update"}
+	}
+
+	return nil
+}
+
+// ValidateSymbolicTarget checks whether target is valid for one symref target.
+//
+// See refs_fsck_symref();
+// root refs are allowed directly, HEAD must point to refs/heads/...,
+// and non-root targets must be valid full refnames rooted at refs/ or
+// worktrees/.
+func ValidateSymbolicTarget(refname string, target string) error {
+	parsed := ParseWorktree(refname)
+	if parsed.BareRefName == "HEAD" && !strings.HasPrefix(target, "refs/heads/") {
+		return &NameError{Name: target, Reason: refname + " must point to refs/heads/..."}
+	}
+
+	if IsRoot(target) {
+		return nil
+	}
+
+	err := Validate(target, Options{})
+	if err != nil {
+		return err
+	}
+
+	if strings.HasPrefix(target, "refs/") {
+		return nil
+	}
+
+	if strings.HasPrefix(target, "worktrees/") {
+		return nil
+	}
+
+	return &NameError{Name: target, Reason: "symref target is not a ref"}
+}
-- 
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