From 224ddcb4b1e54f73c96934a1295a81ee85dd2720 Mon Sep 17 00:00:00 2001
From: oech3 <79379754+oech3@users.noreply.github.com>
Date: Thu, 23 Apr 2026 01:58:41 +0900
Subject: [PATCH 1/2] validate.rs: remove unreachable!()

---
 src/shadow-core/src/validate.rs | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/src/shadow-core/src/validate.rs b/src/shadow-core/src/validate.rs
index 05f7244..0fa93a6 100644
--- a/src/shadow-core/src/validate.rs
+++ b/src/shadow-core/src/validate.rs
@@ -31,10 +31,6 @@ const MAX_USERNAME_LEN: usize = 32;
 ///
 /// Returns `ShadowError::Validation` if the username violates any rule.
 pub fn validate_username(name: &str) -> Result<(), ShadowError> {
-    if name.is_empty() {
-        return Err(ShadowError::Validation("username must not be empty".into()));
-    }
-
     if name.len() > MAX_USERNAME_LEN {
         return Err(ShadowError::Validation(
             format!("username '{name}' exceeds maximum length of {MAX_USERNAME_LEN} characters")
@@ -45,7 +41,7 @@ pub fn validate_username(name: &str) -> Result<(), ShadowError> {
     let mut chars = name.chars();
     // Name is guaranteed non-empty by the check above.
     let Some(first) = chars.next() else {
-        unreachable!("empty name already rejected");
+        return Err(ShadowError::Validation("username must not be empty".into()));
     };
 
     if !first.is_ascii_lowercase() && first != '_' {

From d50a3b65c0e37ba16442c63f3d64faea30010843 Mon Sep 17 00:00:00 2001
From: oech3 <79379754+oech3@users.noreply.github.com>
Date: Thu, 23 Apr 2026 16:08:30 +0900
Subject: [PATCH 2/2] validate.rs: Fix comment

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 src/shadow-core/src/validate.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/shadow-core/src/validate.rs b/src/shadow-core/src/validate.rs
index 0fa93a6..4207ca0 100644
--- a/src/shadow-core/src/validate.rs
+++ b/src/shadow-core/src/validate.rs
@@ -39,7 +39,7 @@ pub fn validate_username(name: &str) -> Result<(), ShadowError> {
     }
 
     let mut chars = name.chars();
-    // Name is guaranteed non-empty by the check above.
+    // Reject empty names by requiring a first character here.
     let Some(first) = chars.next() else {
         return Err(ShadowError::Validation("username must not be empty".into()));
     };