From ddfb261f5778d71162db070aeef21830f9ad9ac9 Mon Sep 17 00:00:00 2001
From: seonghobae <8172694+seonghobae@users.noreply.github.com>
Date: Fri, 21 Aug 2026 04:13:44 +0000
Subject: [PATCH] Optimize max row calculation using vapply instead of sapply

Replaced `sapply` with `vapply(..., numeric(1))` in `llcont.lavaan`
when calculating the maximum number of rows in `mispatts`. This avoids
the overhead of return type deduction and simplification in interpreted
code, improving performance and strictly enforcing type safety.
---
 .jules/bolt.md | 3 +++
 R/llcont.R     | 3 ++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/.jules/bolt.md b/.jules/bolt.md
index f658475..1e89448 100644
--- a/.jules/bolt.md
+++ b/.jules/bolt.md
@@ -15,3 +15,6 @@
 ## 2024-05-15 - [R Performance: ifelse Overhead]
 **Learning:** In R, ifelse evaluates both true and false branches entirely before subsetting, which is very inefficient for vector operations.
 **Action:** Optimize this by preallocating with res <- Y * 0 to preserve attributes and using vectorized subsetting like if any cond res subset <- ...
+## 2026-08-11 - Safe type deduction using vapply
+**Learning:** In R codebases, using `sapply` over a list involves significant overhead to deduce and simplify the return type in interpreted code.
+**Action:** When the return type and length are known, always prefer `vapply(..., FUN.VALUE = type)` over `sapply(...)` for better performance and strict type safety.
diff --git a/R/llcont.R b/R/llcont.R
index d8e496a..16d948a 100644
--- a/R/llcont.R
+++ b/R/llcont.R
@@ -407,7 +407,8 @@ llcont.lavaan <- function(x, ...){
   if(tolower(lavInspect(x, "options")$missing) == "ml.x") stop("cannot handle lavaan models with missing='ml.x'. consider using missing='ml'.", call. = FALSE)
   mispatts <- lavInspect(x, "patterns")
   if(any(class(mispatts) == "list")){
-    npatts <- max(sapply(mispatts, nrow))
+    ## Bolt: replaced sapply(...) with optimized vapply(...) for performance and safety
+    npatts <- max(vapply(mispatts, nrow, numeric(1)))
   } else {
     npatts <- nrow(mispatts)
   }