Don't overwrite schema files that haven't changed

CHANGELOG.md

@@ -3,6 +3,7 @@ This changelog documents the changes between release versions.
 
 ## [Unreleased]
 - Fix incorrect order of results for query requests with more than 10 variable sets (#37)
+- In the CLI update command, don't overwrite schema files that haven't changed ([#49](https://github.com/hasura/ndc-mongodb/pull/49/files))
 
 ## [0.0.4] - 2024-04-12
 - Queries that attempt to compare a column to a column in the query root table, or a related table, will now fail instead of giving the incorrect result ([#22](https://github.com/hasura/ndc-mongodb/pull/22))

crates/configuration/src/directory.rs

@@ -164,7 +164,14 @@ where
 {
     let path = default_file_path(configuration_dir, basename);
     let bytes = serde_json::to_vec_pretty(value)?;
-    fs::write(path.clone(), bytes)
+
+    // Don't write the file if it hasn't changed.
+    if let Ok(existing_bytes) = fs::read(&path).await {
+        if bytes == existing_bytes {
+            return Ok(())
+        }
+    }
+    fs::write(&path, bytes)
         .await
         .with_context(|| format!("error writing {:?}", path))
 }