From 1ab3766ce8d1b96ac2c651da9b8adcf20f9e7b51 Mon Sep 17 00:00:00 2001
From: Gabriel Kaszewski <gabrielkaszewski@gmail.com>
Date: Sat, 16 May 2026 10:57:04 +0200
Subject: [PATCH] fix(postgres): map unique constraint violations to
 DomainError::UniqueViolation

---
 crates/adapters/postgres/src/user.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/crates/adapters/postgres/src/user.rs b/crates/adapters/postgres/src/user.rs
index 395150e..7d26fd8 100644
--- a/crates/adapters/postgres/src/user.rs
+++ b/crates/adapters/postgres/src/user.rs
@@ -166,7 +166,18 @@ impl UserWriter for PgUserRepository {
         .bind(user.updated_at)
         .execute(&self.pool)
         .await
-        .into_domain()
+        .map_err(|e| {
+            if let sqlx::Error::Database(ref db) = e {
+                if db.code().as_deref() == Some("23505") {
+                    return match db.constraint().unwrap_or("") {
+                        "users_username_key" => DomainError::UniqueViolation { field: "username" },
+                        "users_email_key"    => DomainError::UniqueViolation { field: "email" },
+                        _                   => DomainError::UniqueViolation { field: "unknown" },
+                    };
+                }
+            }
+            DomainError::Internal(e.to_string())
+        })
         .map(|_| ())
     }