From 3ccd2d538f38d53310f6b2e11d33a26e1a002546 Mon Sep 17 00:00:00 2001
From: Benedikt Reinartz <filmor@gmail.com>
Date: Thu, 22 Jun 2023 03:21:31 +0200
Subject: [PATCH] Drop support for RUSTLER_NIF_VERSION

---
 CHANGELOG.md            |  6 +++++
 README.md               |  3 ---
 build_common.rs         | 55 -----------------------------------------
 rustler/build.rs        |  8 ------
 rustler/build_common.rs |  1 -
 rustler_sys/build.rs    | 12 +++------
 6 files changed, 10 insertions(+), 75 deletions(-)
 delete mode 100644 build_common.rs
 delete mode 100644 rustler/build.rs
 delete mode 120000 rustler/build_common.rs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0c796143..6843742f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,12 @@ See [`UPGRADE.md`](./UPGRADE.md) for additional help when upgrading to newer ver
 
 ## [unreleased]
 
+### Added
+
+### Changed
+
+* Dropped support for `RUSTLER_NIF_VERSION`
+
 ## [0.29.0] - 2023-06-22
 
 ### Added
diff --git a/README.md b/README.md
index 0748d4da..dcbe6a82 100644
--- a/README.md
+++ b/README.md
@@ -67,9 +67,6 @@ enabled on the dependency:
 rustler = { version = "...", features = ["nif_version_2_16"] }
 ```
 
-For compatibility reasons, this can be defined (and overridden) by setting the
-`RUSTLER_NIF_VERSION` environment variable during build.
-
 #### Community
 
 You can find us in the `#rustler:matrix.org` channel on [Matrix](https://matrix.to/#/#rustler:matrix.org)
diff --git a/build_common.rs b/build_common.rs
deleted file mode 100644
index acf48853..00000000
--- a/build_common.rs
+++ /dev/null
@@ -1,55 +0,0 @@
-mod common {
-    use std::env;
-
-    pub const MIN_SUPPORTED_VERSION: (u32, u32) = (2, 14);
-    pub const MAX_SUPPORTED_VERSION: (u32, u32) = (2, 17);
-
-    fn get_nif_version_from_env(version: &str) -> (u32, u32) {
-        let parts: Vec<Result<_, _>> = version
-            .split('.')
-            .take(2)
-            .map(|n| n.parse::<u32>())
-            .collect();
-
-        let mut nif_version = match &parts[..] {
-            [Ok(major), Ok(minor)] => (*major, *minor),
-            _other => panic!("The RUSTLER_NIF_VERSION is not a valid version"),
-        };
-
-        if nif_version < MIN_SUPPORTED_VERSION {
-            panic!(
-                "The NIF version given from RUSTLER_NIF_VERSION is not supported: {}.{}",
-                nif_version.0, nif_version.1
-            );
-        }
-
-        // TODO: This code will need adjustment if the Erlang developers ever decide to introduce
-        //       a new major NIF version.
-        if nif_version > MAX_SUPPORTED_VERSION {
-            eprintln!(
-                "NIF version {}.{} is not yet supported, falling back to {}.{}",
-                nif_version.0, nif_version.1, MAX_SUPPORTED_VERSION.0, MAX_SUPPORTED_VERSION.1
-            );
-            nif_version = MAX_SUPPORTED_VERSION;
-        }
-
-        nif_version
-    }
-
-    pub fn handle_nif_version_from_env() -> Option<(u32, u32)> {
-        println!("cargo:rerun-if-env-changed=RUSTLER_NIF_VERSION");
-        env::var("RUSTLER_NIF_VERSION").ok().map(|val| {
-            let nif_version = get_nif_version_from_env(&val);
-
-            // Activate all config flags for the supported NIF versions
-            for minor in 0..=nif_version.1 {
-                println!(
-                    "cargo:rustc-cfg=feature=\"nif_version_{}_{}\"",
-                    nif_version.0, minor
-                );
-            }
-
-            nif_version
-        })
-    }
-}
diff --git a/rustler/build.rs b/rustler/build.rs
deleted file mode 100644
index 8da1cefd..00000000
--- a/rustler/build.rs
+++ /dev/null
@@ -1,8 +0,0 @@
-include!("build_common.rs");
-
-fn main() {
-    common::handle_nif_version_from_env();
-
-    // The following lines are important to tell Cargo to recompile if something changes.
-    println!("cargo:rerun-if-changed=build.rs");
-}
diff --git a/rustler/build_common.rs b/rustler/build_common.rs
deleted file mode 120000
index 89a82cd7..00000000
--- a/rustler/build_common.rs
+++ /dev/null
@@ -1 +0,0 @@
-../build_common.rs
\ No newline at end of file
diff --git a/rustler_sys/build.rs b/rustler_sys/build.rs
index af48aefb..98ba5ed9 100644
--- a/rustler_sys/build.rs
+++ b/rustler_sys/build.rs
@@ -2,16 +2,15 @@
 //
 // Generate the NIF APIs that will be built in `src/rustler_sys_api.rs`.
 //
-// This script rely on the `RUSTLER_NIF_VERSION` environment variable
-// and will fallback to the installed OTP version to detect the version.
-// If none of them are available, then we are going to use the latest version.
-//
 
 use regex::Regex;
 use std::fmt::Write;
 use std::path::Path;
 use std::{env, fs};
 
+pub const MIN_SUPPORTED_VERSION: (u32, u32) = (2, 14);
+pub const MAX_SUPPORTED_VERSION: (u32, u32) = (2, 17);
+
 const SNIPPET_NAME: &str = "nif_api.snippet";
 
 trait ApiBuilder {
@@ -880,9 +879,6 @@ fn build_api(b: &mut dyn ApiBuilder, opts: &GenerateOptions) {
     }
 }
 
-include!("build_common.rs");
-use common::*;
-
 fn get_nif_version_from_features() -> (u32, u32) {
     for major in ((MIN_SUPPORTED_VERSION.0)..=(MAX_SUPPORTED_VERSION.0)).rev() {
         for minor in ((MIN_SUPPORTED_VERSION.1)..=(MAX_SUPPORTED_VERSION.1)).rev() {
@@ -898,7 +894,7 @@ fn get_nif_version_from_features() -> (u32, u32) {
 }
 
 fn main() {
-    let nif_version = handle_nif_version_from_env().unwrap_or_else(get_nif_version_from_features);
+    let nif_version = get_nif_version_from_features();
 
     let target_family = if cfg!(target_family = "windows") {
         OsFamily::Win