From 73c0c9f9ad5fd50c173a3c7b8213d030fdb4e0e4 Mon Sep 17 00:00:00 2001
From: Zak Stucke <zakstucke@hotmail.co.uk>
Date: Fri, 16 Feb 2024 17:17:52 +0200
Subject: [PATCH] Adding features to docs

---
 .github/workflows/tests.yml |  4 ++--
 dev_scripts/docs.sh         |  2 +-
 rust/Cargo.lock             |  1 +
 rust/Cargo.toml             |  8 ++++++++
 rust/bitbazaar/lib.rs       |  2 ++
 rust/build.rs               | 14 ++++++++++++++
 6 files changed, 28 insertions(+), 3 deletions(-)
 create mode 100644 rust/build.rs

diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index b5ec752a..fc082da5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -95,8 +95,8 @@ jobs:
         with:
           node-version: "20"
 
-      - name: Install rust toolchain
-        uses: dtolnay/rust-toolchain@stable
+      - name: Install rust toolchain (doc builds use nightly features)
+        uses: dtolnay/rust-toolchain@nightly
 
       - name: Install dependencies
         run: |
diff --git a/dev_scripts/docs.sh b/dev_scripts/docs.sh
index d04c7b11..2eda08bd 100755
--- a/dev_scripts/docs.sh
+++ b/dev_scripts/docs.sh
@@ -15,7 +15,7 @@ js_sub_build () {
 
 # Builds the nested js site:
 rust_sub_build () {
-    rm -rf ./docs/rust_ref && cargo doc --no-deps --manifest-path ./rust/Cargo.toml --target-dir ./docs/rust_ref
+    rm -rf ./docs/rust_ref && cargo +nightly doc --no-deps --manifest-path ./rust/Cargo.toml --target-dir ./docs/rust_ref --all-features
 }
 
 build () {
diff --git a/rust/Cargo.lock b/rust/Cargo.lock
index 20138bdd..7503b983 100644
--- a/rust/Cargo.lock
+++ b/rust/Cargo.lock
@@ -204,6 +204,7 @@ dependencies = [
  "redis",
  "regex",
  "rstest",
+ "rustc_version",
  "serde",
  "serde_json",
  "serial_test",
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index dcf19ef0..428ede3b 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -11,6 +11,14 @@ name = "bitbazaar"
 crate-type = ["lib"]
 path = "bitbazaar/lib.rs"
 
+[build-dependencies]
+rustc_version = "0.4.0"
+
+[package.metadata.docs.rs]
+# We use feature(doc_auto_cfg) so show which features needed for which code.
+# For the features to show in docs.rs, need to tell it to include them:
+all-features = true
+
 [features]
 cli = ['dep:normpath', 'dep:conch-parser', 'dep:homedir']
 redis = ['dep:deadpool-redis', 'dep:redis', 'dep:sha1_smol']
diff --git a/rust/bitbazaar/lib.rs b/rust/bitbazaar/lib.rs
index 86128abf..6d7eb2c6 100644
--- a/rust/bitbazaar/lib.rs
+++ b/rust/bitbazaar/lib.rs
@@ -1,5 +1,7 @@
 #![warn(clippy::disallowed_types)]
 #![warn(missing_docs)]
+// https://stackoverflow.com/questions/61417452/how-to-get-a-feature-requirement-tag-in-the-documentation-generated-by-cargo-do
+#![cfg_attr(all(doc, CHANNEL_NIGHTLY), feature(doc_auto_cfg))]
 
 //! bitbazaar - An assortment of publicly available cross-language utilities useful to my projects.
 
diff --git a/rust/build.rs b/rust/build.rs
new file mode 100644
index 00000000..073426c9
--- /dev/null
+++ b/rust/build.rs
@@ -0,0 +1,14 @@
+use rustc_version::{version_meta, Channel};
+
+// This build script sets the `cfg` flag `CHANNEL_STABLE`, `CHANNEL_BETA`, `CHANNEL_NIGHTLY` or `CHANNEL_DEV` depending on the release channel of the compiler being used.
+// https://stackoverflow.com/questions/61417452/how-to-get-a-feature-requirement-tag-in-the-documentation-generated-by-cargo-do
+fn main() {
+    // Set cfg flags depending on release channel
+    let channel = match version_meta().unwrap().channel {
+        Channel::Stable => "CHANNEL_STABLE",
+        Channel::Beta => "CHANNEL_BETA",
+        Channel::Nightly => "CHANNEL_NIGHTLY",
+        Channel::Dev => "CHANNEL_DEV",
+    };
+    println!("cargo:rustc-cfg={}", channel)
+}