fix: resolve Docker multi-arch and macOS ARM build issues

- Fix Docker to build for native architecture instead of forcing x86_64
- Add macOS cross-compilation environment setup for ARM64 builds
- Skip strip command for cross-compiled ARM64 binaries
- Add file existence check before creating checksums
- Remove hardcoded musl target from Dockerfile

These changes should fix:
1. Docker multi-architecture builds (ARM64 and AMD64)
2. macOS ARM64 cross-compilation from x86_64 runners

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: haasonsaas

.github/workflows/release.yml

@@ -117,19 +117,36 @@ jobs:
           sudo apt-get update
           sudo apt-get install -y musl-tools
       
+      - name: Set up macOS cross-compilation
+        if: matrix.os == 'macos-latest' && matrix.target == 'aarch64-apple-darwin'
+        run: |
+          echo "SDKROOT=$(xcrun -sdk macosx --show-sdk-path)" >> $GITHUB_ENV
+          echo "MACOSX_DEPLOYMENT_TARGET=$(xcrun -sdk macosx --show-sdk-platform-version)" >> $GITHUB_ENV
+      
       - name: Build
         run: cargo build --release --target ${{ matrix.target }}
 
       - name: Strip binary (Linux and macOS)
-        if: matrix.os != 'windows-latest'
+        if: matrix.os != 'windows-latest' && matrix.target != 'aarch64-apple-darwin'
         run: |
           strip target/${{ matrix.target }}/release/${{ matrix.artifact_name }}
       
+      - name: Strip binary (macOS ARM64)
+        if: matrix.target == 'aarch64-apple-darwin'
+        run: |
+          # Skip stripping for cross-compiled ARM64 binary or use lipo if needed
+          echo "Skipping strip for cross-compiled ARM64 binary"
+      
       - name: Create checksum (Unix)
         if: matrix.os != 'windows-latest'
         run: |
           cd target/${{ matrix.target }}/release/
-          sha256sum ${{ matrix.artifact_name }} > ${{ matrix.asset_name }}.sha256
+          if [ -f "${{ matrix.artifact_name }}" ]; then
+            sha256sum ${{ matrix.artifact_name }} > ${{ matrix.asset_name }}.sha256
+          else
+            echo "Binary not found, build may have failed"
+            exit 1
+          fi
           
       - name: Create checksum (Windows)
         if: matrix.os == 'windows-latest'

Dockerfile

@@ -3,22 +3,20 @@ FROM rust:alpine AS builder
 
 RUN apk add --no-cache musl-dev
 
-# Install the musl target
-RUN rustup target add x86_64-unknown-linux-musl
-
 WORKDIR /app
 COPY Cargo.toml Cargo.lock ./
 COPY src ./src
 
-RUN cargo build --release --target x86_64-unknown-linux-musl
-RUN strip target/x86_64-unknown-linux-musl/release/diffscope
+# Build for the native architecture
+RUN cargo build --release
+RUN strip target/release/diffscope
 
 # Runtime stage
 FROM alpine:3.19
 
 RUN apk add --no-cache ca-certificates
 
-COPY --from=builder /app/target/x86_64-unknown-linux-musl/release/diffscope /usr/local/bin/diffscope
+COPY --from=builder /app/target/release/diffscope /usr/local/bin/diffscope
 
 ENTRYPOINT ["diffscope"]
 CMD ["--help"]