From c81b71106ce2e2ed8d4074a91959c6ccb6dc774e Mon Sep 17 00:00:00 2001
From: Scott Mabin <scott@mabez.dev>
Date: Fri, 13 Sep 2024 22:23:48 +0100
Subject: [PATCH] use hand rolled const str to int

---
 esp-config/Cargo.toml |  2 +-
 esp-config/README.md  |  4 ++--
 esp-config/src/lib.rs | 15 +++++++++++----
 esp-wifi/src/lib.rs   |  1 -
 4 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/esp-config/Cargo.toml b/esp-config/Cargo.toml
index 16407e408f3..d63e892b17a 100644
--- a/esp-config/Cargo.toml
+++ b/esp-config/Cargo.toml
@@ -2,7 +2,7 @@
 name = "esp-config"
 version = "0.1.0"
 edition = "2021"
-# rust-version  = "1.82.0"
+rust-version  = "1.77.0"
 
 [dependencies]
 
diff --git a/esp-config/README.md b/esp-config/README.md
index 402a1f358ec..87c7181b0d0 100644
--- a/esp-config/README.md
+++ b/esp-config/README.md
@@ -2,7 +2,7 @@
 
 [![Crates.io](https://img.shields.io/crates/v/esp-config?labelColor=1C2C2E&color=C96329&logo=Rust&style=flat-square)](https://crates.io/crates/esp-config)
 [![docs.rs](https://img.shields.io/docsrs/esp-config?labelColor=1C2C2E&color=C96329&logo=rust&style=flat-square)](https://docs.rs/esp-config)
-![MSRV](https://img.shields.io/badge/MSRV-1.82-blue?labelColor=1C2C2E&style=flat-square)
+![MSRV](https://img.shields.io/badge/MSRV-1.77-blue?labelColor=1C2C2E&style=flat-square)
 ![Crates.io](https://img.shields.io/crates/l/esp-config?labelColor=1C2C2E&style=flat-square)
 [![Matrix](https://img.shields.io/matrix/esp-rs:matrix.org?label=join%20matrix&labelColor=1C2C2E&color=BEC5C9&logo=matrix&style=flat-square)](https://matrix.to/#/#esp-rs:matrix.org)
 
@@ -10,7 +10,7 @@
 
 ## Minimum Supported Rust Version (MSRV)
 
-This crate is guaranteed to compile on stable Rust 1.82 and up. It _might_
+This crate is guaranteed to compile on stable Rust 1.77 and up. It _might_
 compile with older versions but that may change in any new patch release.
 
 ## License
diff --git a/esp-config/src/lib.rs b/esp-config/src/lib.rs
index 019ccfdc150..0329f8b2950 100644
--- a/esp-config/src/lib.rs
+++ b/esp-config/src/lib.rs
@@ -6,12 +6,19 @@ mod generate;
 pub use generate::*;
 
 #[macro_export]
+// TODO from 1.82 we can use <$ty>::from_str_radix(env!($var), 10) instead
 macro_rules! esp_config_int {
     ($ty:ty, $var:expr) => {
-        match <$ty>::from_str_radix(env!($var), 10) {
-            Ok(val) => val,
-            _ => unreachable!(),
-        };
+        const {
+            let mut bytes = env!($var).as_bytes();
+            let mut val: $ty = 0;
+            while let [byte, rest @ ..] = bytes {
+                core::assert!(b'0' <= *byte && *byte <= b'9', "invalid digit");
+                val = val * 10 + (*byte - b'0') as $ty;
+                bytes = rest;
+            }
+            val
+        }
     };
 }
 
diff --git a/esp-wifi/src/lib.rs b/esp-wifi/src/lib.rs
index e53d7388c58..9177a30f388 100644
--- a/esp-wifi/src/lib.rs
+++ b/esp-wifi/src/lib.rs
@@ -89,7 +89,6 @@
 // toolchain doesn't know about that lint, yet)
 #![allow(unknown_lints)]
 #![allow(non_local_definitions)]
-#![feature(const_int_from_str)] // stable in 1.82
 
 extern crate alloc;