From 98a81981ac96c4be97b670d3b4a337c0ea826782 Mon Sep 17 00:00:00 2001
From: jgrusewski <jgrusewski@localhost>
Date: Fri, 8 May 2026 13:09:21 +0200
Subject: [PATCH] fix(build-infra): cargo:rerun-if-env-changed=CUDA_COMPUTE_CAP
 across 6 crates
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Per pearl_build_rs_rerun_if_env_changed, every std::env::var() must be
paired with cargo:rerun-if-env-changed. Task #321 fixed crates/ml/build.rs
(commit e3d082968) but missed 6 sibling build.rs files. Each reads
CUDA_COMPUTE_CAP without registering the rerun directive, so cargo
sees no env-change between e.g. SM 89 (L40S) → SM 90 (H100) workflow
re-submissions and cache-hits the wrong-arch cubin from the previous
run. At runtime, the H100 fails to load the SM 89 cubin with
CUDA_ERROR_NO_BINARY_FOR_GPU on rmsnorm — exactly what killed
train-multi-seed-vlv8c (commit 0371d6a76, post-Class-B chain).

Files (all add `println!("cargo:rerun-if-env-changed=CUDA_COMPUTE_CAP")`
just before the env::var() read):
- crates/ml-dqn/build.rs (rmsnorm — root cause of vlv8c failure)
- crates/ml-ensemble/build.rs
- crates/ml-explainability/build.rs
- crates/ml-ppo/build.rs
- crates/ml-supervised/build.rs
- crates/ml-core/build.rs

Atomic single commit per feedback_no_partial_refactor.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
---
 crates/ml-core/build.rs           | 1 +
 crates/ml-dqn/build.rs            | 8 +++++++-
 crates/ml-ensemble/build.rs       | 1 +
 crates/ml-explainability/build.rs | 1 +
 crates/ml-ppo/build.rs            | 1 +
 crates/ml-supervised/build.rs     | 1 +
 6 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/crates/ml-core/build.rs b/crates/ml-core/build.rs
index 22c156cd3..ad5a0afaa 100644
--- a/crates/ml-core/build.rs
+++ b/crates/ml-core/build.rs
@@ -29,6 +29,7 @@ fn main() {
     println!("cargo:rerun-if-changed={}", common_header_path.display());
 
     // Detect GPU architecture from env or default to sm_80
+    println!("cargo:rerun-if-env-changed=CUDA_COMPUTE_CAP");
     let cuda_compute_cap = std::env::var("CUDA_COMPUTE_CAP").unwrap_or_else(|_| "80".to_string());
     let arch = format!("sm_{cuda_compute_cap}");
 
diff --git a/crates/ml-dqn/build.rs b/crates/ml-dqn/build.rs
index 74486d572..853c774a7 100644
--- a/crates/ml-dqn/build.rs
+++ b/crates/ml-dqn/build.rs
@@ -21,7 +21,13 @@ fn main() {
 
     println!("cargo:rerun-if-changed={}", common_header_path.display());
 
-    // Detect GPU architecture from env or default to sm_80
+    // Detect GPU architecture from env or default to sm_80.
+    // CRITICAL: pair env::var() with rerun-if-env-changed per
+    // pearl_build_rs_rerun_if_env_changed, otherwise sccache + cubin caches
+    // hit-on-SHA across arch changes (e.g., SM 89 L40S → SM 90 H100), and
+    // training fails at runtime with CUDA_ERROR_NO_BINARY_FOR_GPU on rmsnorm
+    // cubin load (commit 0371d6a76 on H100, post-Class-B chain).
+    println!("cargo:rerun-if-env-changed=CUDA_COMPUTE_CAP");
     let cuda_compute_cap = std::env::var("CUDA_COMPUTE_CAP").unwrap_or_else(|_| "80".to_string());
     let arch = format!("sm_{cuda_compute_cap}");
 
diff --git a/crates/ml-ensemble/build.rs b/crates/ml-ensemble/build.rs
index 654739587..90a92d514 100644
--- a/crates/ml-ensemble/build.rs
+++ b/crates/ml-ensemble/build.rs
@@ -13,6 +13,7 @@ fn main() {
     let kernel_dir = Path::new("src");
 
     // Detect GPU architecture from env or default to sm_80
+    println!("cargo:rerun-if-env-changed=CUDA_COMPUTE_CAP");
     let cuda_compute_cap = std::env::var("CUDA_COMPUTE_CAP").unwrap_or_else(|_| "80".to_string());
     let arch = format!("sm_{cuda_compute_cap}");
 
diff --git a/crates/ml-explainability/build.rs b/crates/ml-explainability/build.rs
index 51c1765d0..799dbf628 100644
--- a/crates/ml-explainability/build.rs
+++ b/crates/ml-explainability/build.rs
@@ -13,6 +13,7 @@ fn main() {
     let kernel_dir = Path::new("src");
 
     // Detect GPU architecture from env or default to sm_80 (matches crates/ml/build.rs).
+    println!("cargo:rerun-if-env-changed=CUDA_COMPUTE_CAP");
     let cuda_compute_cap = std::env::var("CUDA_COMPUTE_CAP").unwrap_or_else(|_| "80".to_string());
     let arch = format!("sm_{cuda_compute_cap}");
 
diff --git a/crates/ml-ppo/build.rs b/crates/ml-ppo/build.rs
index 1da83cbe8..6c044ccb2 100644
--- a/crates/ml-ppo/build.rs
+++ b/crates/ml-ppo/build.rs
@@ -29,6 +29,7 @@ fn main() {
     println!("cargo:rerun-if-changed={}", common_header_path.display());
 
     // Detect GPU architecture from env or default to sm_80
+    println!("cargo:rerun-if-env-changed=CUDA_COMPUTE_CAP");
     let cuda_compute_cap = std::env::var("CUDA_COMPUTE_CAP").unwrap_or_else(|_| "80".to_string());
     let arch = format!("sm_{cuda_compute_cap}");
 
diff --git a/crates/ml-supervised/build.rs b/crates/ml-supervised/build.rs
index dd1f05508..ef2abb27e 100644
--- a/crates/ml-supervised/build.rs
+++ b/crates/ml-supervised/build.rs
@@ -25,6 +25,7 @@ fn main() {
     let manifest_dir = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
 
     // Detect GPU architecture from env or default to sm_80 (L40S / A100).
+    println!("cargo:rerun-if-env-changed=CUDA_COMPUTE_CAP");
     let cuda_compute_cap = std::env::var("CUDA_COMPUTE_CAP").unwrap_or_else(|_| "80".to_string());
     let arch = format!("sm_{cuda_compute_cap}");