Stabilize sort_text format when MRU is inactive

Summary: Change assign_sort_text to take Option<Option<usize>> so that "no MRU system" (None, e.g. the wasm path) preserves the compact sort_text format ("0", "1", etc.), while "MRU active but item not found" (Some(None)) uses the extended format with rank 9999. Previously all items got the extended format whenever the MRU system was active, even items not in the MRU, which was a surface-area change to all non-wasm completion responses.

Reviewed By: jvansch1

Differential Revision: D93248048

fbshipit-source-id: 296df656d0e96efae6b750d4d86ecbd975f92884

Author: kinto0

pyrefly/lib/lsp/wasm/completion.rs

@@ -84,7 +84,15 @@ impl RankedCompletion {
 
 /// All completion ranking logic lives here. Assigns `sort_text` to each item
 /// based on its source classification, name prefix, compatibility, and MRU rank.
-fn assign_sort_text(ranked: &mut RankedCompletion, mru_rank: Option<usize>) {
+///
+/// `mru_rank` uses two levels of `Option`:
+/// - `None` means the MRU system is not active (e.g. wasm path). sort_text uses
+///   the compact base format (`"0"`, `"1"`, etc.).
+/// - `Some(None)` means the MRU system is active but the item was not found in
+///   the MRU list. sort_text uses the extended format with rank 9999 so it sorts
+///   after MRU-matched items.
+/// - `Some(Some(rank))` means the item was found at position `rank` in the MRU.
+fn assign_sort_text(ranked: &mut RankedCompletion, mru_rank: Option<Option<usize>>) {
     let is_deprecated = ranked
         .item
         .tags
@@ -115,12 +123,18 @@ fn assign_sort_text(ranked: &mut RankedCompletion, mru_rank: Option<usize>) {
         }
     };
 
-    if let Some(rank) = mru_rank {
-        let rank = rank.min(9999);
-        ranked.item.sort_text = Some(format!("{base}.{rank:04}.{}", ranked.item.label));
-        ranked.item.preselect = if rank == 0 { Some(true) } else { None };
-    } else {
-        ranked.item.sort_text = Some(base);
+    match mru_rank {
+        Some(Some(rank)) => {
+            let rank = rank.min(9999);
+            ranked.item.sort_text = Some(format!("{base}.{rank:04}.{}", ranked.item.label));
+            ranked.item.preselect = if rank == 0 { Some(true) } else { None };
+        }
+        Some(None) => {
+            ranked.item.sort_text = Some(format!("{base}.9999.{}", ranked.item.label));
+        }
+        None => {
+            ranked.item.sort_text = Some(base);
+        }
     }
 }
 
@@ -950,9 +964,7 @@ impl Transaction<'_> {
             Self::add_function_call_parens(&mut result, supports_snippet_completions);
         }
         for ranked in &mut result {
-            let mru_rank = mru_index
-                .as_mut()
-                .map(|index| (*index)(&ranked.item).unwrap_or(9999).min(9999));
+            let mru_rank = mru_index.as_mut().map(|index| (*index)(&ranked.item));
             assign_sort_text(ranked, mru_rank);
         }
         (result.into_iter().map(|r| r.item).collect(), is_incomplete)