fix(ci): Simplify GitHub actions caches (#5104)

* Disable fmt cache and create shared clippy cache

* Make Cargo.lock check use the shared clippy cache

* Add a TODO for Windows Rust cache path

* Fix quoting for Windows path

* Use correct sharedKey spelling

.github/workflows/continous-integration-os.yml

@@ -91,6 +91,19 @@ jobs:
           override: true
 
       - uses: Swatinem/rust-cache@v1
+        # TODO: change Rust cache target directory on Windows,
+        #       or remove this workaround once the build is more efficient (#3005).
+        #with:
+        #  workspaces: ". -> C:\\zebra-target"
+
+      - name: Change target output directory on Windows
+        # Windows doesn't have enough space on the D: drive, so we redirect the build output to the
+        # larger C: drive.
+        # TODO: Remove this workaround once the build is more efficient (#3005).
+        if: matrix.os == 'windows-latest'
+        run: |
+          mkdir "C:\\zebra-target"
+          echo "CARGO_TARGET_DIR=C:\\zebra-target" | Out-File -FilePath "$env:GITHUB_ENV" -Encoding utf8 -Append
 
       - name: cargo fetch
         uses: actions-rs/cargo@v1.0.3
@@ -123,15 +136,6 @@ jobs:
           echo "PROPTEST_CASES=1" >> $GITHUB_ENV
           echo "PROPTEST_MAX_SHRINK_ITERS=1024" >> $GITHUB_ENV
 
-      - name: Change target output directory on Windows
-        # Windows doesn't have enough space on the D: drive, so we redirect the build output to the
-        # larger C: drive.
-        # TODO: Remove this workaround once the build is more efficient (#3005).
-        if: matrix.os == 'windows-latest'
-        run: |
-          mkdir C:\zebra-target
-          echo "CARGO_TARGET_DIR=C:\zebra-target" | Out-File -FilePath $env:GITHUB_ENV -Encoding utf8 -Append
-
       # Modified from:
       # https://github.com/zcash/librustzcash/blob/c48bb4def2e122289843ddb3cb2984c325c03ca0/.github/workflows/ci.yml#L20-L33
       #
@@ -218,6 +222,9 @@ jobs:
           override: true
 
       - uses: Swatinem/rust-cache@v1
+        with:
+          # TODO: change to shared-key when we switch to Swatinem/rust-cache@v2
+          sharedKey: "clippy-cargo-lock"
 
       - name: Check Cargo.lock is up to date
         uses: actions-rs/cargo@v1.0.3

.github/workflows/lint.yml

@@ -83,6 +83,9 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - uses: Swatinem/rust-cache@v1
+        with:
+          # TODO: change to shared-key when we switch to Swatinem/rust-cache@v2
+          sharedKey: "clippy-cargo-lock"
 
       - name: Run clippy action to produce annotations
         uses: actions-rs/clippy-check@v1.0.7
@@ -127,7 +130,9 @@ jobs:
           components: rustfmt
           override: true
 
-      - uses: Swatinem/rust-cache@v1
+      # We don't cache `fmt` outputs because the job is quick,
+      # and we want to use the limited GitHub actions cache space for slower jobs.
+      #- uses: Swatinem/rust-cache@v1
 
       - uses: actions-rs/cargo@v1.0.3
         with: