fix: diffing two migration directories on sqlite

The pattern match was not exhaustive where it should have been.

closes prisma/prisma#13633

migration-engine/core/src/commands/diff.rs

@@ -105,7 +105,7 @@ async fn json_rpc_diff_target_to_connector(
         }
         DiffTarget::Migrations(PathContainer { path }) => {
             let provider = migration_connector::migrations_directory::read_provider_from_lock_file(path);
-            match (provider, shadow_database_url) {
+            match (provider.as_deref(), shadow_database_url) {
                 (Some(provider), Some(shadow_database_url)) => {
                     let mut connector = crate::connector_for_provider(&provider)?;
                     let directories = migration_connector::migrations_directory::list_migrations(Path::new(path))?;
@@ -117,14 +117,21 @@ async fn json_rpc_diff_target_to_connector(
                         .await?;
                     Ok(Some((connector, schema)))
                 }
-                (provider, None) if provider.as_deref() != Some("sqlite") => Err(ConnectorError::from_msg(
+                (Some("sqlite"), None) => {
+                    let mut connector = crate::connector_for_provider("sqlite")?;
+                    let directories = migration_connector::migrations_directory::list_migrations(Path::new(path))?;
+                    let schema = connector
+                        .database_schema_from_diff_target(McDiff::Migrations(&directories), None)
+                        .await?;
+                    Ok(Some((connector, schema)))
+                }
+                (Some(_), None) => Err(ConnectorError::from_msg(
                     "You must pass the --shadow-database-url if you want to diff a migrations directory.".to_owned(),
                 )),
                 (None, _) => Err(ConnectorError::from_msg(
                     "Could not determine the connector from the migrations directory (missing migrations_lock.toml)."
                         .to_owned(),
                 )),
-                _ => unreachable!("no provider, no shadow database url for migrations target"),
             }
         }
     }

migration-engine/migration-engine-tests/tests/migrations/diff.rs

@@ -412,6 +412,40 @@ fn diffing_mongo_schemas_to_script_returns_a_nice_error() {
     expected.assert_eq(&diff_error(params));
 }
 
+#[test]
+fn diff_sqlite_migration_directories() {
+    let base_dir = tempfile::tempdir().unwrap();
+    let base_dir_2 = tempfile::tempdir().unwrap();
+    let base_dir_str = base_dir.path().to_str().unwrap();
+    let base_dir_str_2 = base_dir_2.path().to_str().unwrap();
+
+    let migrations_lock_path = base_dir.path().join("migration_lock.toml");
+    std::fs::write(
+        &migrations_lock_path,
+        &"provider = \"sqlite\"",
+    ).unwrap();
+    let migrations_lock_path = base_dir_2.path().join("migration_lock.toml");
+    std::fs::write(
+        &migrations_lock_path,
+        &"provider = \"sqlite\"",
+    ).unwrap();
+
+    let params = DiffParams {
+        exit_code: None,
+        from: DiffTarget::Migrations(PathContainer {
+            path: base_dir_str.to_owned(),
+        }),
+        script: true,
+        shadow_database_url: None,
+        to: DiffTarget::Migrations(PathContainer {
+            path: base_dir_str_2.to_owned(),
+        }),
+    };
+
+    tok(migration_core::migration_api(None, None).unwrap().diff(params)).unwrap();
+    // it's ok!
+}
+
 #[test]
 fn diffing_mongo_schemas_works() {
     let tempdir = tempfile::tempdir().unwrap();