Merge pull request #6450 from obycode/feat/current-contract

[Clarity-4] implement `current-contract`

Author: obycode

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to the versioning scheme outlined in the [README.md](RE
 - Creates epoch 3.3 and costs-4 in preparation for a hardfork to activate Clarity 4
 - Adds support for new Clarity 4 builtins (not activated until epoch 3.3):
   - `contract-hash?`
+  - `current-contract`
   - `block-time`
   - `to-ascii?`
 - Added `contract_cost_limit_percentage` to the miner config file — sets the percentage of a block’s execution cost at which, if a large non-boot contract call would cause a BlockTooBigError, the miner will stop adding further non-boot contract calls and only include STX transfers and boot contract calls for the remainder of the block.

clarity/src/vm/analysis/arithmetic_checker/mod.rs

@@ -143,7 +143,7 @@ impl ArithmeticOnlyChecker<'_> {
             match native_var {
                 ContractCaller | TxSender | TotalLiquidMicroSTX | BlockHeight | BurnBlockHeight
                 | Regtest | TxSponsor | Mainnet | ChainId | StacksBlockHeight | TenureHeight
-                | BlockTime => Err(Error::VariableForbidden(native_var)),
+                | BlockTime | CurrentContract => Err(Error::VariableForbidden(native_var)),
                 NativeNone | NativeTrue | NativeFalse => Ok(()),
             }
         } else {

clarity/src/vm/analysis/type_checker/v2_05/mod.rs

@@ -330,9 +330,9 @@ fn type_reserved_variable(variable_name: &str) -> Result<Option<TypeSignature>,
             NativeFalse => TypeSignature::BoolType,
             TotalLiquidMicroSTX => TypeSignature::UIntType,
             Regtest => TypeSignature::BoolType,
-            TxSponsor | Mainnet | ChainId | StacksBlockHeight | TenureHeight | BlockTime => {
+            TxSponsor | Mainnet | ChainId | StacksBlockHeight | TenureHeight | BlockTime | CurrentContract => {
                 return Err(CheckErrors::Expects(
-                    "tx-sponsor, mainnet, chain-id, stacks-block-height, tenure-height, and block-time should not reach here in 2.05".into(),
+                    "tx-sponsor, mainnet, chain-id, stacks-block-height, tenure-height, block-time, and current-contract should not reach here in 2.05".into(),
                 )
                 .into())
             }

clarity/src/vm/analysis/type_checker/v2_1/mod.rs

@@ -1022,6 +1022,7 @@ fn type_reserved_variable(
             Regtest => TypeSignature::BoolType,
             Mainnet => TypeSignature::BoolType,
             ChainId => TypeSignature::UIntType,
+            CurrentContract => TypeSignature::PrincipalType,
             BlockTime => TypeSignature::UIntType,
         };
         Ok(Some(var_type))

clarity/src/vm/docs/mod.rs

@@ -125,6 +125,15 @@ to the same contract principal.",
     example: "(print contract-caller) ;; Will print out a Stacks address of the transaction sender",
 };
 
+const CURRENT_CONTRACT_KEYWORD: SimpleKeywordAPI = SimpleKeywordAPI {
+    name: "current-contract",
+    snippet: "current-contract",
+    output_type: "principal",
+    description: "Returns the principal of the current contract.",
+    example:
+        "(print current-contract) ;; Will print out the Stacks address of the current contract",
+};
+
 const STACKS_BLOCK_HEIGHT_KEYWORD: SimpleKeywordAPI = SimpleKeywordAPI {
     name: "stacks-block-height",
     snippet: "stacks-block-height",
@@ -2690,6 +2699,7 @@ pub fn make_keyword_reference(variable: &NativeVariables) -> Option<KeywordAPI>
         NativeVariables::Mainnet => MAINNET_KEYWORD.clone(),
         NativeVariables::ChainId => CHAINID_KEYWORD.clone(),
         NativeVariables::TxSponsor => TX_SPONSOR_KEYWORD.clone(),
+        NativeVariables::CurrentContract => CURRENT_CONTRACT_KEYWORD.clone(),
         NativeVariables::BlockTime => BLOCK_TIME_KEYWORD.clone(),
     };
     Some(KeywordAPI {