Vendor things

third-party/vendor/thiserror/build.rs

@@ -0,0 +1,119 @@
+use std::env;
+use std::ffi::OsString;
+use std::path::Path;
+use std::process::{self, Command, Stdio};
+
+fn main() {
+    println!("cargo:rerun-if-changed=build/probe.rs");
+
+    let error_generic_member_access;
+    let consider_rustc_bootstrap;
+    if compile_probe(false) {
+        // This is a nightly or dev compiler, so it supports unstable features
+        // regardless of RUSTC_BOOTSTRAP. No need to rerun build script if
+        // RUSTC_BOOTSTRAP is changed.
+        error_generic_member_access = true;
+        consider_rustc_bootstrap = false;
+    } else if let Some(rustc_bootstrap) = env::var_os("RUSTC_BOOTSTRAP") {
+        if compile_probe(true) {
+            // This is a stable or beta compiler for which the user has set
+            // RUSTC_BOOTSTRAP to turn on unstable features. Rerun build script
+            // if they change it.
+            error_generic_member_access = true;
+            consider_rustc_bootstrap = true;
+        } else if rustc_bootstrap == "1" {
+            // This compiler does not support the generic member access API in
+            // the form that thiserror expects. No need to pay attention to
+            // RUSTC_BOOTSTRAP.
+            error_generic_member_access = false;
+            consider_rustc_bootstrap = false;
+        } else {
+            // This is a stable or beta compiler for which RUSTC_BOOTSTRAP is
+            // set to restrict the use of unstable features by this crate.
+            error_generic_member_access = false;
+            consider_rustc_bootstrap = true;
+        }
+    } else {
+        // Without RUSTC_BOOTSTRAP, this compiler does not support the generic
+        // member access API in the form that thiserror expects, but try again
+        // if the user turns on unstable features.
+        error_generic_member_access = false;
+        consider_rustc_bootstrap = true;
+    }
+
+    if error_generic_member_access {
+        println!("cargo:rustc-cfg=error_generic_member_access");
+    }
+
+    if consider_rustc_bootstrap {
+        println!("cargo:rerun-if-env-changed=RUSTC_BOOTSTRAP");
+    }
+}
+
+fn compile_probe(rustc_bootstrap: bool) -> bool {
+    if env::var_os("RUSTC_STAGE").is_some() {
+        // We are running inside rustc bootstrap. This is a highly non-standard
+        // environment with issues such as:
+        //
+        //     https://github.com/rust-lang/cargo/issues/11138
+        //     https://github.com/rust-lang/rust/issues/114839
+        //
+        // Let's just not use nightly features here.
+        return false;
+    }
+
+    let rustc = cargo_env_var("RUSTC");
+    let out_dir = cargo_env_var("OUT_DIR");
+    let probefile = Path::new("build").join("probe.rs");
+
+    // Make sure to pick up Cargo rustc configuration.
+    let mut cmd = if let Some(wrapper) = env::var_os("RUSTC_WRAPPER") {
+        let mut cmd = Command::new(wrapper);
+        // The wrapper's first argument is supposed to be the path to rustc.
+        cmd.arg(rustc);
+        cmd
+    } else {
+        Command::new(rustc)
+    };
+
+    if !rustc_bootstrap {
+        cmd.env_remove("RUSTC_BOOTSTRAP");
+    }
+
+    cmd.stderr(Stdio::null())
+        .arg("--edition=2018")
+        .arg("--crate-name=thiserror")
+        .arg("--crate-type=lib")
+        .arg("--emit=dep-info,metadata")
+        .arg("--out-dir")
+        .arg(out_dir)
+        .arg(probefile);
+
+    if let Some(target) = env::var_os("TARGET") {
+        cmd.arg("--target").arg(target);
+    }
+
+    // If Cargo wants to set RUSTFLAGS, use that.
+    if let Ok(rustflags) = env::var("CARGO_ENCODED_RUSTFLAGS") {
+        if !rustflags.is_empty() {
+            for arg in rustflags.split('\x1f') {
+                cmd.arg(arg);
+            }
+        }
+    }
+
+    match cmd.status() {
+        Ok(status) => status.success(),
+        Err(_) => false,
+    }
+}
+
+fn cargo_env_var(key: &str) -> OsString {
+    env::var_os(key).unwrap_or_else(|| {
+        eprintln!(
+            "Environment variable ${} is not set during execution of build script",
+            key,
+        );
+        process::exit(1);
+    })
+}