Use Rust 1.81 to crossbuild FFI (#252)

Signed-off-by: Shaobo He <shaobohe@amazon.com>

Author: shaobo-he-aws

.github/workflows/run_cedar_java_reusable.yml

@@ -40,8 +40,7 @@ jobs:
           ref: ${{ inputs.cedar_policy_ref }}
           path: ./cedar
       - name: Prepare Rust Build
-        # zigbuild issue: rust-cross/cargo-zigbuild#289
-        run: rustup install 1.81 && rustup default 1.81 && rustup component add rustfmt 
+        run: rustup install stable && rustup default stable 
       - name: Configure CedarJavaFFI for CI build
         run: bash configure_ci_build.sh
       - name: Check FFI Formatting

CedarJava/build.gradle

@@ -107,37 +107,39 @@ def rustJavaTargets = [
         'x86_64-unknown-linux-gnu' : 'linux/x86_64'
 ]
 
-tasks.register('installCargoZigbuild', Exec) {
-    group 'Build'
-    description 'Installs Cargo Zigbuild for Rust compilation.'
+def RustVersion = '1.81'
 
-    commandLine 'cargo', 'install', 'cargo-zigbuild@0.19.3'
+tasks.register('installRequiredRustVersion', Exec) {
+  group 'Build'
+  description 'Install required Rust version.'
+  commandLine 'rustup', 'install', RustVersion
 }
 
-tasks.register('installRustTargets') {
-    dependsOn('installCargoZigbuild')
+tasks.register('installCargoZigbuild', Exec) {
+    dependsOn('installRequiredRustVersion')
     group 'Build'
-    description 'Installs Rust platform build targets.'
+    description 'Installs Cargo Zigbuild for Rust compilation.'
 
-    doLast {
-        rustLibraryTargets.keySet().forEach { rustTarget ->
-            exec {
-                commandLine 'rustup', 'target', 'add', rustTarget
-            }
-        }
-    }
+    commandLine 'cargo', '+' + RustVersion, 'install', 'cargo-zigbuild@0.19.3'
 }
 
 tasks.register('compileFFI') {
-    dependsOn('installRustTargets')
+    dependsOn('installCargoZigbuild')
     group 'Build'
     description 'Compiles Foreign Function Interface libraries.'
+    exec {
+        workingDir = ffiDir
+        commandLine 'rustup', 'override', 'set', RustVersion
+    }
 
     doLast {
         rustLibraryTargets.forEach { rustTarget, libraryFile ->
+            exec {
+                commandLine 'rustup', 'target', 'add', rustTarget, '--toolchain', RustVersion
+            }
             exec {
                 workingDir = ffiDir
-                commandLine 'cargo', 'zigbuild', '--features', 'partial-eval', '--release', '--target', rustTarget
+                commandLine 'cargo', '+' + RustVersion, 'zigbuild', '--features', 'partial-eval', '--release', '--target', rustTarget
             }
 
             def sourcePath = "${ffiDir}/target/${rustTarget}/release/${libraryFile}"