feat: add Slither static analysis support and update README with installation instructions

Author: YukiTsuchida

Makefile

@@ -19,3 +19,7 @@ else
 	@echo "'SOURCE={ContractName}' is required, e.g. make abi SOURCE=CrossSimpleModule"
 	@exit 1
 endif
+
+.PHONY: slither
+slither:
+	slither .

README.md

@@ -39,3 +39,10 @@ interface IContractModule {
 To generate encoders and decoders in solidity from proto files, you need to use the code generator [solidity-protobuf](https://github.com/datachainlab/solidity-protobuf).
 
 Currently, [this version](https://github.com/datachainlab/solidity-protobuf/commit/3def6706178e5407497f3d01b8f0ceb17b32108d) is required.
+
+Install Slither and use it for static analysis.
+
+```
+pip3 install slither-analyzer
+make slither
+```

slither.config.json

@@ -0,0 +1,5 @@
+{
+  "exclude_dependencies": true,
+  "exclude_informational": true,
+  "filter_paths": "node_modules|lib|test|script|src/proto"
+}

src/Migrations.sol

@@ -5,7 +5,7 @@ import {IIBCHandler} from "@hyperledger-labs/yui-ibc-solidity/contracts/core/25-
 
 // IBCKeeper keeps the contracts of IBC
 abstract contract IBCKeeper {
-    IIBCHandler ibcHandler;
+    IIBCHandler internal immutable ibcHandler;
 
     constructor(IIBCHandler handler_) {
         ibcHandler = handler_;

src/core/IBCKeeper.sol

@@ -36,9 +36,11 @@ abstract contract TxAtomicSimple is IBCKeeper, PacketHandler, ContractRegistry {
             CrossContext(pdc.tx_id, txIndexParticipant, pdc.tx.signers), pdc.tx.call_info
         ) returns (bytes memory ret) {
             ack.status = PacketAcknowledgementCall.CommitStatus.COMMIT_STATUS_OK;
+            // slither-disable-next-line reentrancy-events
             emit OnContractCall(pdc.tx_id, txIndexParticipant, true, ret);
         } catch (bytes memory) {
             ack.status = PacketAcknowledgementCall.CommitStatus.COMMIT_STATUS_FAILED;
+            // slither-disable-next-line reentrancy-events
             emit OnContractCall(pdc.tx_id, txIndexParticipant, false, new bytes(0));
         }