breaking(mysql): assume all non-binary collations compatible with str (#3924)

cc #3400 (comment)

comment in `sqlx-mysql/src/collation.rs` for explanation

fixes #3200
fixes #3387
fixes #3390
fixes #3409

Author: abonander

.github/workflows/sqlx.yml

@@ -419,7 +419,7 @@ jobs:
     runs-on: ubuntu-24.04
     strategy:
       matrix:
-        mariadb: [ verylatest, 11_4, 10_11, 10_4 ]
+        mariadb: [ verylatest, 11_8, 11_4, 10_11, 10_6 ]
         runtime: [ async-std, tokio ]
         tls: [ native-tls, rustls-aws-lc-rs, rustls-ring, none ]
     needs: check
@@ -446,7 +446,7 @@ jobs:
         env:
           DATABASE_URL: mysql://root:password@localhost:3306/sqlx
           SQLX_OFFLINE_DIR: .sqlx
-          RUSTFLAGS: --cfg mariadb_${{ matrix.mariadb }}
+          RUSTFLAGS: --cfg mariadb="${{ matrix.mariadb }}"
 
       # Run the `test-attr` test again to cover cleanup.
       - run: >
@@ -457,7 +457,7 @@ jobs:
         env:
           DATABASE_URL: mysql://root:password@localhost:3306/sqlx
           SQLX_OFFLINE_DIR: .sqlx
-          RUSTFLAGS: --cfg mariadb_${{ matrix.mariadb }}
+          RUSTFLAGS: --cfg mariadb="${{ matrix.mariadb }}"
 
       # Remove test artifacts
       - run: cargo clean -p sqlx
@@ -471,7 +471,7 @@ jobs:
         env:
           SQLX_OFFLINE: true
           SQLX_OFFLINE_DIR: .sqlx
-          RUSTFLAGS: -D warnings --cfg mariadb_${{ matrix.mariadb }}
+          RUSTFLAGS: -D warnings --cfg mariadb="${{ matrix.mariadb }}"
 
       # Test macros in offline mode (still needs DATABASE_URL to run)
       - run: >
@@ -483,7 +483,7 @@ jobs:
           DATABASE_URL: mysql://root:password@localhost:3306/sqlx
           SQLX_OFFLINE: true
           SQLX_OFFLINE_DIR: .sqlx
-          RUSTFLAGS: --cfg mariadb_${{ matrix.mariadb }}
+          RUSTFLAGS: --cfg mariadb="${{ matrix.mariadb }}"
 
       # client SSL authentication
 
@@ -500,4 +500,4 @@ jobs:
           --features any,mysql,macros,migrate,_unstable-all-types,runtime-${{ matrix.runtime }},tls-${{ matrix.tls }}
         env:
           DATABASE_URL: mysql://root@localhost:3306/sqlx?sslmode=verify_ca&ssl-ca=.%2Ftests%2Fcerts%2Fca.crt&ssl-key=.%2Ftests%2Fcerts%2Fkeys%2Fclient.key&ssl-cert=.%2Ftests%2Fcerts%2Fclient.crt
-          RUSTFLAGS: --cfg mariadb_${{ matrix.mariadb }}
+          RUSTFLAGS: --cfg mariadb="${{ matrix.mariadb }}"

Cargo.lock

@@ -210,6 +210,9 @@ cast_sign_loss = 'deny'
 # See `clippy.toml`
 disallowed_methods = 'deny'
 
+[lints.rust]
+unexpected_cfgs = { level = 'warn', check-cfg = ['cfg(mariadb, values(any()))'] }
+
 #
 # Any
 #

Cargo.toml

@@ -240,11 +240,11 @@ impl RawSql {
     ///
     /// Otherwise, you might want to add `LIMIT 1` to your query.
     #[inline]
-    pub async fn fetch_optional<'e, E, DB>(self, executor: E) -> crate::Result<DB::Row>
+    pub async fn fetch_optional<'e, E, DB>(self, executor: E) -> crate::Result<Option<DB::Row>>
     where
         DB: Database,
         E: Executor<'e, Database = DB>,
     {
-        executor.fetch_one(self).await
+        executor.fetch_optional(self).await
     }
 }