td/util: Add docstring to evaluate_qe and rename unit_id

Summary:
This is a frequent source of confusion. The intern endpoint will convert the
version number to an appropriate ID based on the configuration for the universe.

Make it clear for callers that they don't need to specify anything besides the
version number.

Reviewed By: rjbailey

Differential Revision: D67342025

fbshipit-source-id: ac8f484f6ae3406954eecf8d2cfd5a542a92ed37

td_util/src/qe.rs

@@ -19,9 +19,12 @@ pub enum QEParamValue {
     Int(i64),
 }
 
+/// Evaluate the given phabricator version number against the QE universe.
+///
+/// The API internally converts to the right unit ID based on the universe.
 #[cfg(all(fbcode_build, target_os = "linux"))]
 pub async fn evaluate_qe(
-    unit_id: u64,
+    phabricator_version_number: u64,
     universe: &str,
     param: &str,
     expect: QEParamValue,
@@ -31,7 +34,7 @@ pub async fn evaluate_qe(
     use tracing::info;
 
     let value_for_logging: serde_json::Value;
-    let qe = QE2::from_unit_id(unit_id, &[universe]).await;
+    let qe = QE2::from_unit_id(phabricator_version_number, &[universe]).await;
     let ret = match &expect {
         QEParamValue::Bool(expect) => {
             let qe_value = qe.get_bool(universe, param, false);
@@ -55,7 +58,7 @@ pub async fn evaluate_qe(
         "Check {param} from QE {universe}, value {value_for_logging} (expected {expect_str}): {ret}"
     );
     crate::scuba!(event: QE_CHECK, data: json!({
-        "unit_id": unit_id,
+        "phabricator_version_number": phabricator_version_number,
         "param": param,
         "universe": universe,
         "value": value_for_logging,
@@ -68,7 +71,7 @@ pub async fn evaluate_qe(
 
 #[cfg(not(all(fbcode_build, target_os = "linux")))]
 pub async fn evaluate_qe(
-    _unit_id: u64,
+    _phabricator_version_number: u64,
     _universe: &str,
     _param: &str,
     _expect: QEParamValue,
@@ -80,11 +83,17 @@ pub async fn evaluate_qe(
 /// Sync API for checking QE2.
 /// This does not work from existing `run_as_sync` contexts, and will deadlock.
 pub fn evaluate_qe_sync(
-    unit_id: u64,
+    phabricator_version_number: u64,
     universe: &str,
     param: &str,
     expect: QEParamValue,
     step: supertd_events::Step,
 ) -> bool {
-    crate::executor::run_as_sync(evaluate_qe(unit_id, universe, param, expect, step))
+    crate::executor::run_as_sync(evaluate_qe(
+        phabricator_version_number,
+        universe,
+        param,
+        expect,
+        step,
+    ))
 }