From e5de7c5bea70d04d38b369625dc9ee77a302c1af Mon Sep 17 00:00:00 2001
From: Volker Mische <volker.mische@gmail.com>
Date: Fri, 22 Apr 2022 18:08:29 +0100
Subject: [PATCH] chore: make sure that the documention is available on doc.rs
 (#21)

Due to the CUDA kernel compilation the documentation creation on
docs.rs fails. With this commit we skip that step for the docs.rs
platform, so that the documentation is successfully built there.

Fixes #19.
---
 .circleci/config.yml | 18 ++++++++++++++++++
 ec-gpu-gen/build.rs  |  9 ++++++++-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 1be5d12..d9ceb66 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -149,6 +149,21 @@ jobs:
       - run:
           name: Run cargo release build
           command: cargo build --workspace --release
+  rustdoc:
+    executor: default
+    environment:
+      # Making sure that the documentation can be built without having the NVIDIA toolkit
+      # installed.
+      DOCS_RS: true
+    steps:
+      - *restore-workspace
+      - *restore-cache
+      - run: echo 'export PATH="$HOME:~/.cargo/bin:$PATH"' >> $BASH_ENV && source $BASH_ENV
+      - run:
+          name: Run rustdoc
+          command: |
+            cargo rustdoc --package ec-gpu --all-features -- -D warnings
+            cargo rustdoc --package ec-gpu-gen --all-features -- -D warnings
 
 workflows:
   version: 2.1
@@ -206,3 +221,6 @@ workflows:
       - build:
           requires:
             - cargo_fetch
+      - rustdoc:
+          requires:
+            - cargo_fetch
diff --git a/ec-gpu-gen/build.rs b/ec-gpu-gen/build.rs
index 4b4fb8b..0a0e55d 100644
--- a/ec-gpu-gen/build.rs
+++ b/ec-gpu-gen/build.rs
@@ -18,6 +18,13 @@ fn main() {
     #[path = "src/source.rs"]
     mod source;
 
+    // This is a hack for the case when the documentation is built on docs.rs. For the
+    // documentation  we don't need a properly compiled kernel, but just some arbitrary bytes.
+    if env::var("DOCS_RS").is_ok() {
+        println!("cargo:rustc-env=CUDA_KERNEL_FATBIN=../build.rs");
+        return;
+    }
+
     let kernel_source = source::gen_source::<Bls12, source::Limb32>();
 
     let out_dir = env::var("OUT_DIR").expect("OUT_DIR was not set.");
@@ -69,7 +76,7 @@ fn main() {
             .arg(&fatbin_path)
             .arg(&source_path)
             .status()
-            .expect("Cannot run nvcc.");
+            .expect("Cannot run nvcc. Install the NVIDIA toolkit or disable the `cuda` feature.");
 
         if !status.success() {
             panic!(