fixup GHA

Author: lobsterkatie

.github/workflows/build.yml

@@ -105,9 +105,12 @@ jobs:
       # `job_build` can't see `job_install_deps` and what it returned)
       dependency_cache_key: ${{ needs.job_install_deps.outputs.dependency_cache_key }}
 
+  # This isn't a full `yarn build` using sucrase - it's just the cache from the normal build, with `build/cjs` and
+  # `build/esm` overwritten by sucrase. This way we don't need to worry about all of the other random stuff which
+  # packages build, because it will already be there.
   job_build_with_sucrase:
-    name: Build with sucrase
-    needs: job_install_deps
+    name: Sucrase Build
+    needs: [job_install_deps, job_build]
     runs-on: ubuntu-latest
     timeout-minutes: 20
     steps:
@@ -122,19 +125,20 @@ jobs:
         with:
           path: ${{ env.CACHED_DEPENDENCY_PATHS }}
           key: ${{ needs.job_install_deps.outputs.dependency_cache_key }}
-      - name: Check build cache
+      - name: Check tsc build cache
         uses: actions/cache@v2
-        id: cache_built_packages
+        with:
+          path: ${{ env.CACHED_BUILD_PATHS }}
+          key: ${{ env.BUILD_CACHE_KEY }}
+      - name: Check sucrase build cache
+        uses: actions/cache@v2
+        id: cache_built_sucrase_packages
         with:
           path: ${{ env.CACHED_BUILD_PATHS }}
           key: ${{ env.BUILD_CACHE_KEY }}-sucrase
       - name: Build packages with sucrase
-        # Under normal circumstances, using the git SHA as a cache key, there shouldn't ever be a cache hit on the built
-        # packages, and so `yarn build` should always run. This `if` check is therefore only there for testing CI issues
-        # where the built packages are beside the point. In that case, you can change `BUILD_CACHE_KEY` (at the top of
-        # this file) to a constant and skip rebuilding all of the packages each time CI runs.
-        if: steps.cache_built_packages.outputs.cache-hit == ''
-        run: 'yarn build:rollup && yarn build:types && yarn build:bundle'
+        if: steps.cache_built_sucrase_packages.outputs.cache-hit == ''
+        run: 'yarn build:rollup'
     outputs:
       # this needs to be passed on, because the `needs` context only looks at direct ancestors (so steps which depend on
       # `job_build` can't see `job_install_deps` and what it returned)