feat(bundler): check target arch at runtime, closes #2286 (#2422)

Author: lucasfernog

.changes/bundler-runtime-target-arch.md

@@ -0,0 +1,5 @@
+---
+"tauri-bundler": patch
+---
+
+Check target architecture at runtime running `$ RUSTC_BOOTSTRAP=1 rustc -Z unstable-options --print target-spec-json` and parsing the `llvm-target` field, fixing macOS M1 sidecar check until we can compile the CLI with M1 target on GitHub Actions.

tooling/bundler/src/bundle/platform.rs

@@ -1,3 +1,11 @@
+use std::{io::Cursor, process::Command};
+
+#[derive(Debug, serde::Deserialize)]
+struct TargetSpec {
+  #[serde(rename = "llvm-target")]
+  llvm_target: String,
+}
+
 // Copyright 2019-2021 Tauri Programme within The Commons Conservancy
 // SPDX-License-Identifier: Apache-2.0
 // SPDX-License-Identifier: MIT
@@ -12,18 +20,36 @@
 /// * Errors:
 ///     * Unexpected system config
 pub fn target_triple() -> Result<String, crate::Error> {
-  let arch = if cfg!(target_arch = "x86") {
-    "i686"
-  } else if cfg!(target_arch = "x86_64") {
-    "x86_64"
-  } else if cfg!(target_arch = "arm") {
-    "armv7"
-  } else if cfg!(target_arch = "aarch64") {
-    "aarch64"
+  let output = Command::new("rustc")
+    .args(&["-Z", "unstable-options", "--print", "target-spec-json"])
+    .env("RUSTC_BOOTSTRAP", "1")
+    .output()?;
+  let arch = if output.status.success() {
+    let target_spec: TargetSpec = serde_json::from_reader(Cursor::new(output.stdout))?;
+    target_spec
+      .llvm_target
+      .split('-')
+      .next()
+      .unwrap()
+      .to_string()
   } else {
-    return Err(crate::Error::ArchError(String::from(
-      "Unable to determine target-architecture",
-    )));
+    super::common::print_info(&format!(
+      "failed to determine target arch using rustc, error: `{}`. The fallback is the architecture of the machine that compiled this crate.",
+      String::from_utf8_lossy(&output.stderr),
+    ))?;
+    if cfg!(target_arch = "x86") {
+      "i686".into()
+    } else if cfg!(target_arch = "x86_64") {
+      "x86_64".into()
+    } else if cfg!(target_arch = "arm") {
+      "armv7".into()
+    } else if cfg!(target_arch = "aarch64") {
+      "aarch64".into()
+    } else {
+      return Err(crate::Error::ArchError(String::from(
+        "Unable to determine target-architecture",
+      )));
+    }
   };
 
   let os = if cfg!(target_os = "linux") {