Revert "Support stable rust for compiling the runtime (#13580)"

This reverts commit 0b985aa.

primitives/io/Cargo.toml

@@ -9,7 +9,6 @@ repository = "https://github.com/paritytech/substrate/"
 description = "I/O for Substrate runtimes"
 documentation = "https://docs.rs/sp-io"
 readme = "README.md"
-build = "build.rs"
 
 [package.metadata.docs.rs]
 targets = ["x86_64-unknown-linux-gnu"]
@@ -38,9 +37,6 @@ ed25519-dalek = { version = "1.0.1", default-features = false, optional = true }
 # Force the usage of ed25519, this is being used in `ed25519-dalek`.
 ed25519 = { version = "1.5.2", optional = true }
 
-[build-dependencies]
-rustversion = "1.0.6"
-
 [features]
 default = ["std"]
 std = [

primitives/io/src/lib.rs

@@ -19,7 +19,7 @@
 
 #![warn(missing_docs)]
 #![cfg_attr(not(feature = "std"), no_std)]
-#![cfg_attr(enable_alloc_error_handler, feature(alloc_error_handler))]
+#![cfg_attr(not(feature = "std"), feature(alloc_error_handler))]
 #![cfg_attr(
 	feature = "std",
 	doc = "Substrate runtime standard library as compiled when linked with Rust's standard library."
@@ -1643,7 +1643,7 @@ pub fn panic(info: &core::panic::PanicInfo) -> ! {
 }
 
 /// A default OOM handler for WASM environment.
-#[cfg(all(not(feature = "disable_oom"), enable_alloc_error_handler))]
+#[cfg(all(not(feature = "disable_oom"), not(feature = "std")))]
 #[alloc_error_handler]
 pub fn oom(_: core::alloc::Layout) -> ! {
 	#[cfg(feature = "improved_panic_error_reporting")]

utils/wasm-builder/README.md

@@ -77,13 +77,8 @@ Wasm builder requires the following prerequisites for building the Wasm binary:
 
 - rust nightly + `wasm32-unknown-unknown` toolchain
 
-or
-
-- rust stable and version at least 1.68.0 + `wasm32-unknown-unknown` toolchain
-
-If a specific rust is installed with `rustup`, it is important that the wasm target is
-installed as well. For example if installing the rust from 20.02.2020 using `rustup
-install nightly-2020-02-20`, the wasm target needs to be installed as well `rustup target add
-wasm32-unknown-unknown --toolchain nightly-2020-02-20`.
+If a specific rust nightly is installed with `rustup`, it is important that the wasm target is installed
+as well. For example if installing the rust nightly from 20.02.2020 using `rustup install nightly-2020-02-20`,
+the wasm target needs to be installed as well `rustup target add wasm32-unknown-unknown --toolchain nightly-2020-02-20`.
 
 License: Apache-2.0

utils/wasm-builder/src/lib.rs

@@ -100,12 +100,8 @@
 //!
 //! - rust nightly + `wasm32-unknown-unknown` toolchain
 //!
-//! or
-//!
-//! - rust stable and version at least 1.68.0 + `wasm32-unknown-unknown` toolchain
-//!
-//! If a specific rust is installed with `rustup`, it is important that the wasm target is
-//! installed as well. For example if installing the rust from 20.02.2020 using `rustup
+//! If a specific rust nightly is installed with `rustup`, it is important that the wasm target is
+//! installed as well. For example if installing the rust nightly from 20.02.2020 using `rustup
 //! install nightly-2020-02-20`, the wasm target needs to be installed as well `rustup target add
 //! wasm32-unknown-unknown --toolchain nightly-2020-02-20`.
 
@@ -115,11 +111,9 @@ use std::{
 	path::{Path, PathBuf},
 	process::Command,
 };
-use version::Version;
 
 mod builder;
 mod prerequisites;
-mod version;
 mod wasm_project;
 
 pub use builder::{WasmBuilder, WasmBuilderSelectProject};
@@ -178,59 +172,53 @@ fn copy_file_if_changed(src: PathBuf, dst: PathBuf) {
 	}
 }
 
-/// Get a cargo command that should be used to invoke the compilation.
-fn get_cargo_command() -> CargoCommand {
+/// Get a cargo command that compiles with nightly
+fn get_nightly_cargo() -> CargoCommand {
 	let env_cargo =
 		CargoCommand::new(&env::var("CARGO").expect("`CARGO` env variable is always set by cargo"));
 	let default_cargo = CargoCommand::new("cargo");
+	let rustup_run_nightly = CargoCommand::new_with_args("rustup", &["run", "nightly", "cargo"]);
 	let wasm_toolchain = env::var(WASM_BUILD_TOOLCHAIN).ok();
 
 	// First check if the user requested a specific toolchain
-	if let Some(cmd) =
-		wasm_toolchain.map(|t| CargoCommand::new_with_args("rustup", &["run", &t, "cargo"]))
-	{
+	if let Some(cmd) = wasm_toolchain.and_then(|t| get_rustup_nightly(Some(t))) {
 		cmd
-	} else if env_cargo.supports_substrate_wasm_env() {
+	} else if env_cargo.is_nightly() {
 		env_cargo
-	} else if default_cargo.supports_substrate_wasm_env() {
+	} else if default_cargo.is_nightly() {
 		default_cargo
+	} else if rustup_run_nightly.is_nightly() {
+		rustup_run_nightly
 	} else {
-		// If no command before provided us with a cargo that supports our Substrate wasm env, we
-		// try to search one with rustup. If that fails as well, we return the default cargo and let
-		// the prequisities check fail.
-		get_rustup_command().unwrap_or(default_cargo)
+		// If no command before provided us with a nightly compiler, we try to search one
+		// with rustup. If that fails as well, we return the default cargo and let the prequisities
+		// check fail.
+		get_rustup_nightly(None).unwrap_or(default_cargo)
 	}
 }
 
-/// Get the newest rustup command that supports our Substrate wasm env.
-///
-/// Stable versions are always favored over nightly versions even if the nightly versions are
-/// newer.
-fn get_rustup_command() -> Option<CargoCommand> {
+/// Get a nightly from rustup. If `selected` is `Some(_)`, a `CargoCommand` using the given
+/// nightly is returned.
+fn get_rustup_nightly(selected: Option<String>) -> Option<CargoCommand> {
 	let host = format!("-{}", env::var("HOST").expect("`HOST` is always set by cargo"));
 
-	let output = Command::new("rustup").args(&["toolchain", "list"]).output().ok()?.stdout;
-	let lines = output.as_slice().lines();
-
-	let mut versions = Vec::new();
-	for line in lines.filter_map(|l| l.ok()) {
-		let rustup_version = line.trim_end_matches(&host);
-
-		let cmd = CargoCommand::new_with_args("rustup", &["run", &rustup_version, "cargo"]);
+	let version = match selected {
+		Some(selected) => selected,
+		None => {
+			let output = Command::new("rustup").args(&["toolchain", "list"]).output().ok()?.stdout;
+			let lines = output.as_slice().lines();
 
-		if !cmd.supports_substrate_wasm_env() {
-			continue
-		}
-
-		let Some(cargo_version) = cmd.version() else { continue; };
+			let mut latest_nightly = None;
+			for line in lines.filter_map(|l| l.ok()) {
+				if line.starts_with("nightly-") && line.ends_with(&host) {
+					// Rustup prints them sorted
+					latest_nightly = Some(line.clone());
+				}
+			}
 
-		versions.push((cargo_version, rustup_version.to_string()));
-	}
-
-	// Sort by the parsed version to get the latest version (greatest version) at the end of the
-	// vec.
-	versions.sort_by_key(|v| v.0);
-	let version = &versions.last()?.1;
+			latest_nightly?.trim_end_matches(&host).into()
+		},
+	};
 
 	Some(CargoCommand::new_with_args("rustup", &["run", &version, "cargo"]))
 }
@@ -240,23 +228,17 @@ fn get_rustup_command() -> Option<CargoCommand> {
 struct CargoCommand {
 	program: String,
 	args: Vec<String>,
-	version: Option<Version>,
 }
 
 impl CargoCommand {
 	fn new(program: &str) -> Self {
-		let version = Self::extract_version(program, &[]);
-
-		CargoCommand { program: program.into(), args: Vec::new(), version }
+		CargoCommand { program: program.into(), args: Vec::new() }
 	}
 
 	fn new_with_args(program: &str, args: &[&str]) -> Self {
-		let version = Self::extract_version(program, args);
-
 		CargoCommand {
 			program: program.into(),
 			args: args.iter().map(ToString::to_string).collect(),
-			version,
 		}
 	}
 
@@ -266,40 +248,20 @@ impl CargoCommand {
 		cmd
 	}
 
-	fn extract_version(program: &str, args: &[&str]) -> Option<Version> {
-		let version = Command::new(program)
-			.args(args)
-			.arg("--version")
-			.output()
-			.ok()
-			.and_then(|o| String::from_utf8(o.stdout).ok())?;
-
-		Version::extract(&version)
-	}
-
-	/// Returns the version of this cargo command or `None` if it failed to extract the version.
-	fn version(&self) -> Option<Version> {
-		self.version
-	}
-
-	/// Check if the supplied cargo command supports our Substrate wasm environment.
-	///
-	/// This means that either the cargo version is at minimum 1.68.0 or this is a nightly cargo.
-	///
-	/// Assumes that cargo version matches the rustc version.
-	fn supports_substrate_wasm_env(&self) -> bool {
+	/// Check if the supplied cargo command is a nightly version
+	fn is_nightly(&self) -> bool {
 		// `RUSTC_BOOTSTRAP` tells a stable compiler to behave like a nightly. So, when this env
 		// variable is set, we can assume that whatever rust compiler we have, it is a nightly
 		// compiler. For "more" information, see:
 		// https://github.com/rust-lang/rust/blob/fa0f7d0080d8e7e9eb20aa9cbf8013f96c81287f/src/libsyntax/feature_gate/check.rs#L891
-		if env::var("RUSTC_BOOTSTRAP").is_ok() {
-			return true
-		}
-
-		let Some(version) = self.version() else { return false };
-
-		// Check if major and minor are greater or equal than 1.68 or this is a nightly.
-		version.major > 1 || (version.major == 1 && version.minor >= 68) || version.is_nightly
+		env::var("RUSTC_BOOTSTRAP").is_ok() ||
+			self.command()
+				.arg("--version")
+				.output()
+				.map_err(|_| ())
+				.and_then(|o| String::from_utf8(o.stdout).map_err(|_| ()))
+				.unwrap_or_default()
+				.contains("-nightly")
 	}
 }
 

utils/wasm-builder/src/prerequisites.rs

@@ -35,13 +35,10 @@ fn print_error_message(message: &str) -> String {
 ///
 /// Returns the versioned cargo command on success.
 pub(crate) fn check() -> Result<CargoCommandVersioned, String> {
-	let cargo_command = crate::get_cargo_command();
+	let cargo_command = crate::get_nightly_cargo();
 
-	if !cargo_command.supports_substrate_wasm_env() {
-		return Err(print_error_message(
-			"Cannot compile the WASM runtime: no compatible Rust compiler found!\n\
-			 Install at least Rust 1.68.0 or a recent nightly version.",
-		))
+	if !cargo_command.is_nightly() {
+		return Err(print_error_message("Rust nightly not installed, please install it!"))
 	}
 
 	check_wasm_toolchain_installed(cargo_command)