Add comment explaining slot0

aloelabs · Oct 11, 2023 · 07f14a4 · 07f14a4
1 parent 03139dc
commit 07f14a4
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Showing 3 changed files with 38 additions and 25 deletions.
diff --git a/.github/workflows/ci-test.yml b/.github/workflows/ci-test.yml
@@ -48,7 +48,8 @@ jobs:
   #         echo "## Lint result" >> $GITHUB_STEP_SUMMARY
   #         echo "✅ Passed" >> $GITHUB_STEP_SUMMARY
 
-  build:
+  test-core:
+    name: Test core
     runs-on: "ubuntu-latest"
     steps:
       - uses: actions/checkout@v3
@@ -58,17 +59,30 @@ jobs:
         uses: foundry-rs/foundry-toolchain@v1
         with:
           version: nightly
-      - name: Build core
+      - name: "Generate a fuzz seed that changes weekly to avoid burning through RPC allowance"
+        run: >
+          echo "FOUNDRY_FUZZ_SEED=$(
+            echo $(($EPOCHSECONDS - $EPOCHSECONDS % 604800))
+          )" >> $GITHUB_ENV
+      - name: "Install Node.js"
+        uses: "actions/setup-node@v3"
+        with:
+          cache: "yarn"
+          node-version: "lts/*"
+      - name: Test core
+        env:
+          CHECK_CONSTANTS: true
+          CHECK_STORAGE_LAYOUTS: true
+          CHECK_LEDGER_PURITY: true
+          CHECK_FORGE_TESTS: true
+          CHECK_COVERAGE: true
         run: |
           cd "${GITHUB_WORKSPACE}/core"
-          forge build
-      - name: Build periphery
-        run: |
-          cd "${GITHUB_WORKSPACE}/periphery"
-          forge build
+          echo "## Testing core" >> $GITHUB_STEP_SUMMARY
+          ./test.sh
 
-  test:
-    needs: ["build"]
+  test-periphery:
+    name: Test periphery
     runs-on: "ubuntu-latest"
     steps:
       - uses: actions/checkout@v3
@@ -78,27 +92,11 @@ jobs:
         uses: foundry-rs/foundry-toolchain@v1
         with:
           version: nightly
-      - name: "Install Node.js"
-        uses: "actions/setup-node@v3"
-        with:
-          cache: "yarn"
-          node-version: "lts/*"
       - name: "Generate a fuzz seed that changes weekly to avoid burning through RPC allowance"
         run: >
           echo "FOUNDRY_FUZZ_SEED=$(
             echo $(($EPOCHSECONDS - $EPOCHSECONDS % 604800))
           )" >> $GITHUB_ENV
-      - name: Test core
-        env:
-          CHECK_CONSTANTS: true
-          CHECK_STORAGE_LAYOUTS: true
-          CHECK_LEDGER_PURITY: true
-          CHECK_FORGE_TESTS: true
-          CHECK_COVERAGE: true
-        run: |
-          cd "${GITHUB_WORKSPACE}/core"
-          echo "## Testing core" >> $GITHUB_STEP_SUMMARY
-          ./test.sh
       - name: Test periphery
         run: |
           cd "${GITHUB_WORKSPACE}/periphery"

diff --git a/core/src/Borrower.sol b/core/src/Borrower.sol
@@ -102,6 +102,15 @@ contract Borrower is IUniswapV3MintCallback {
     /// @notice The lender of `TOKEN1`
     Lender public immutable LENDER1;
 
+    /**
+     * @notice The `Borrower`'s only mutable storage. Lowest 144 bits store the lower/upper bounds of up to 3 Uniswap
+     * positions, encoded by `Positions.zip`. Next 64 bits are unused within the `Borrower` and available to users as
+     * "free" storage － no additional sstore's. These 208 bits (144 + 64) are passed to `IManager.callback`, and get
+     * updated when the callback returns a non-zero value. The next 40 bits are either 0 or `unleashLiquidationTime`,
+     * as explained in the `Warn` event docs. The highest 8 bits represent the current `State` enum, plus 128. We add
+     * 128 (i.e. set the highest bit to 1) so that the slot is always non-zero, even in the absence of Uniswap
+     * positions － this saves gas.
+     */
     uint256 public slot0;
 
     modifier onlyInModifyCallback() {

diff --git a/core/test/Borrower.t.sol b/core/test/Borrower.t.sol
@@ -82,6 +82,12 @@ contract BorrowerTest is Test, IManager, IUniswapV3SwapCallback {
         vm.createSelectFork(vm.rpcUrl("anvil"));
     }
 
+    function test_stateMaskIsAddition(uint8 state) external {
+        state = uint8(bound(state, 0, 127));
+        assertEq(state | 0x80, state + 128);
+        assertEq((state | 0x80) & 0x7f, state);
+    }
+
     function test_permissionsModify(
         address owner,
         address caller,