refactor: log an error for duplicate decorators

Author: boblat

src/puyapy/awst_build/contract.py

@@ -296,7 +296,6 @@ def visit_function(
             if (len(list(filter(None, (subroutine_dec, abimethod_dec, baremethod_dec))))) > 1:
                 logger.error(
                     f"ARC-4 contract member functions"
-                    f" (other than __init__ or approval / clear program methods)"
                     f" must not be annotated with more than one of"
                     f" @{constants.SUBROUTINE_HINT_ALIAS},"
                     f" @{constants.ABIMETHOD_DECORATOR_ALIAS},"

src/puyapy/awst_build/utils.py

@@ -73,6 +73,9 @@ def get_decorators_by_fullname(
 
         # map alias to canonical name
         full_name = DECORATOR_ALIAS_MAPPING.get(full_name, full_name)
+
+        if full_name in result:
+            logger.error("duplicate decorator", location=ctx.node_location(d))
         result[full_name] = d
     return result
 

tests/test_expected_output/arc4.test

@@ -480,17 +480,27 @@ from algopy import arc4, public, subroutine
 class MyContract(arc4.ARC4Contract):    
     @public
     @subroutine
-    def a(self) -> None: ## E: ARC-4 contract member functions (other than __init__ or approval / clear program methods) must not be annotated with more than one of @algopy.subroutine, @algopy.arc4.abimethod, @algopy.public, or @algopy.arc4.baremethod
+    def a(self) -> None: ## E: ARC-4 contract member functions must not be annotated with more than one of @algopy.subroutine, @algopy.arc4.abimethod, @algopy.public, or @algopy.arc4.baremethod
         pass
 
     @arc4.abimethod
     @subroutine
-    def b(self) -> None: ## E: ARC-4 contract member functions (other than __init__ or approval / clear program methods) must not be annotated with more than one of @algopy.subroutine, @algopy.arc4.abimethod, @algopy.public, or @algopy.arc4.baremethod
+    def b(self) -> None: ## E: ARC-4 contract member functions must not be annotated with more than one of @algopy.subroutine, @algopy.arc4.abimethod, @algopy.public, or @algopy.arc4.baremethod
         pass
 
     @arc4.abimethod
+    @public ## E: duplicate decorator
+    def c(self) -> None: 
+        pass
+
+    @arc4.abimethod
+    @arc4.abimethod ## E: duplicate decorator
+    def d(self) -> None:
+        pass
+
     @public
-    def c(self) -> None:
+    @public ## E: duplicate decorator
+    def e(self) -> None:
         pass
 
 ## case: bad_signatures