ci: do main build with fully generated stm32-metapac.

.github/workflows/rust.yml

@@ -12,7 +12,7 @@ env:
 jobs:
   all:
     runs-on: ubuntu-20.04
-    needs: [build, test, metapac_gen]
+    needs: [build, test]
     steps:
       - name: Done
         run: exit 0
@@ -45,12 +45,3 @@ jobs:
       - uses: actions/checkout@v2
       - name: Test
         run: cd embassy && cargo test
-
-  metapac_gen:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-        with:
-          submodules: true
-      - name: Generate pregenerated metapac
-        run: cd stm32-metapac-gen; cargo run --release

ci.sh

@@ -7,6 +7,13 @@ export RUSTFLAGS=-Dwarnings
 
 find -name '*.rs' -not -path '*target*' -not -path '*stm32-metapac-gen/out/*'  | xargs rustfmt --check  --skip-children --unstable-features --edition 2018
 
+# Generate stm32-metapac
+# for some reason Cargo stomps the cache if we don't specify --target.
+# This happens with vanilla Cargo, not just cargo-batch. Bug?
+(cd stm32-metapac-gen; cargo run --release --target x86_64-unknown-linux-gnu)
+rm -rf stm32-metapac
+mv stm32-metapac-gen/out stm32-metapac
+
 cargo batch  \
     --- build --release --manifest-path embassy/Cargo.toml --target thumbv7em-none-eabi \
     --- build --release --manifest-path embassy/Cargo.toml --target thumbv7em-none-eabi --features log,executor-agnostic \