diff options
12 files changed, 31 insertions, 84 deletions
diff --git a/Changelog.md b/Changelog.md index 2ded6bf2..a0471ce5 100644 --- a/Changelog.md +++ b/Changelog.md @@ -34,6 +34,7 @@ Breaking Changes: * Type Checker: Disallow arithmetic operations for boolean variables. * Type Checker: Disallow conversions between ``bytesX`` and ``uintY`` of different size. * Type Checker: Disallow specifying base constructor arguments multiple times in the same inheritance hierarchy. This was already the case in the experimental 0.5.0 mode. + * Type Checker: Disallow uninitialized storage variables. This was already the case in the experimental 0.5.0 mode. * Type Checker: Only accept a single ``bytes`` type for ``.call()`` (and family), ``keccak256()``, ``sha256()`` and ``ripemd160()``. * Remove obsolete ``std`` directory from the Solidity repository. This means accessing ``https://github.com/ethereum/soldity/blob/develop/std/*.sol`` (or ``https://github.com/ethereum/solidity/std/*.sol`` in Remix) will not be possible. * Syntax Checker: Named return values in function types are an error. diff --git a/docs/frequently-asked-questions.rst b/docs/frequently-asked-questions.rst index 0d6fa033..75693bdd 100644 --- a/docs/frequently-asked-questions.rst +++ b/docs/frequently-asked-questions.rst @@ -306,48 +306,11 @@ independent copy of the state variable is created in memory and is another issue). The modifications to this independent copy do not carry back to ``data1`` or ``data2``. -A common mistake is to declare a local variable and assume that it will -be created in memory, although it will be created in storage:: - - /// THIS CONTRACT CONTAINS AN ERROR - - pragma solidity ^0.4.0; - - contract C { - uint someVariable; - uint[] data; - - function f() public { - uint[] x; - x.push(2); - data = x; - } - } - -The type of the local variable ``x`` is ``uint[] storage``, but since -storage is not dynamically allocated, it has to be assigned from -a state variable before it can be used. So no space in storage will be -allocated for ``x``, but instead it functions only as an alias for -a pre-existing variable in storage. - -What will happen is that the compiler interprets ``x`` as a storage -pointer and will make it point to the storage slot ``0`` by default. -This has the effect that ``someVariable`` (which resides at storage -slot ``0``) is modified by ``x.push(2)``. - -The correct way to do this is the following:: - - pragma solidity ^0.4.0; - - contract C { - uint someVariable; - uint[] data; - - function f() public { - uint[] x = data; - x.push(2); - } - } +.. warning:: + Prior to version 0.5.0, a common mistake was to declare a local variable and assume that it will + be created in memory, although it will be created in storage. Using such a variable without initializing + it could lead to unexpected behavior. Starting from 0.5.0, however, storage variables have to be initialized, + which should prevent these kinds of mistakes. ****************** Advanced Questions diff --git a/libsolidity/analysis/TypeChecker.cpp b/libsolidity/analysis/TypeChecker.cpp index 20e423e6..a11b1879 100644 --- a/libsolidity/analysis/TypeChecker.cpp +++ b/libsolidity/analysis/TypeChecker.cpp @@ -1073,10 +1073,7 @@ bool TypeChecker::visit(VariableDeclarationStatement const& _statement) if (varDecl.referenceLocation() == VariableDeclaration::Location::Default) errorText += " Did you mean '<type> memory " + varDecl.name() + "'?"; solAssert(m_scope, ""); - if (v050) - m_errorReporter.declarationError(varDecl.location(), errorText); - else - m_errorReporter.warning(varDecl.location(), errorText); + m_errorReporter.declarationError(varDecl.location(), errorText); } } else if (dynamic_cast<MappingType const*>(type(varDecl).get())) diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp index ce00931b..fbc6a9c6 100644 --- a/test/libsolidity/SolidityEndToEndTest.cpp +++ b/test/libsolidity/SolidityEndToEndTest.cpp @@ -7878,6 +7878,7 @@ BOOST_AUTO_TEST_CASE(tuples) char const* sourceCode = R"( contract C { uint[] data; + uint[] m_c; function g() internal returns (uint a, uint b, uint[] storage c) { return (1, 2, data); } @@ -7890,7 +7891,7 @@ BOOST_AUTO_TEST_CASE(tuples) uint a; uint b; (a, b) = this.h(); if (a != 5 || b != 6) return 1; - uint[] storage c; + uint[] storage c = m_c; (a, b, c) = g(); if (a != 1 || b != 2 || c[0] != 3) return 2; (a, b) = (b, a); @@ -9585,7 +9586,7 @@ BOOST_AUTO_TEST_CASE(calling_uninitialized_function_through_array) { assembly { mstore(0, 7) return(0, 0x20) } } mutex = 1; // Avoid re-executing this function if we jump somewhere. - function() internal returns (uint)[200] x; + function() internal returns (uint)[200] memory x; x[0](); return 2; } @@ -10113,7 +10114,7 @@ BOOST_AUTO_TEST_CASE(copy_internal_function_array_to_storage) function() internal returns (uint)[20] x; int mutex; function one() public returns (uint) { - function() internal returns (uint)[20] xmem; + function() internal returns (uint)[20] memory xmem; x = xmem; return 3; } diff --git a/test/libsolidity/syntaxTests/array/uninitialized_storage_var.sol b/test/libsolidity/syntaxTests/array/uninitialized_storage_var.sol new file mode 100644 index 00000000..363d8147 --- /dev/null +++ b/test/libsolidity/syntaxTests/array/uninitialized_storage_var.sol @@ -0,0 +1,9 @@ +contract C { + function f() { + uint[] storage x; + uint[10] storage y; + } +} +// ---- +// DeclarationError: (31-47): Uninitialized storage pointer. +// DeclarationError: (51-69): Uninitialized storage pointer. diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/206_storage_location_local_variables.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/206_storage_location_local_variables.sol index 5199e5d7..868d7bc8 100644 --- a/test/libsolidity/syntaxTests/nameAndTypeResolution/206_storage_location_local_variables.sol +++ b/test/libsolidity/syntaxTests/nameAndTypeResolution/206_storage_location_local_variables.sol @@ -1,11 +1,9 @@ contract C { - function f() public { - uint[] storage x; + uint[] m_x; + function f() public view { + uint[] storage x = m_x; uint[] memory y; - uint[] memory z; - x;y;z; + x;y; } } // ---- -// Warning: (47-63): Uninitialized storage pointer. -// Warning: (17-135): Function state mutability can be restricted to pure diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/211_uninitialized_mapping_array_variable.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/211_uninitialized_mapping_array_variable.sol index 80467491..edae7549 100644 --- a/test/libsolidity/syntaxTests/nameAndTypeResolution/211_uninitialized_mapping_array_variable.sol +++ b/test/libsolidity/syntaxTests/nameAndTypeResolution/211_uninitialized_mapping_array_variable.sol @@ -5,4 +5,4 @@ contract C { } } // ---- -// Warning: (52-85): Uninitialized storage pointer. +// DeclarationError: (52-85): Uninitialized storage pointer. diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/212_uninitialized_mapping_array_variable_050.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/212_uninitialized_mapping_array_variable_050.sol deleted file mode 100644 index f2028690..00000000 --- a/test/libsolidity/syntaxTests/nameAndTypeResolution/212_uninitialized_mapping_array_variable_050.sol +++ /dev/null @@ -1,9 +0,0 @@ -pragma experimental "v0.5.0"; -contract C { - function f() pure public { - mapping(uint => uint)[] storage x; - x; - } -} -// ---- -// DeclarationError: (82-115): Uninitialized storage pointer. diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/233_non_initialized_references.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/233_non_initialized_references.sol index 9d8d4834..a0b6f71e 100644 --- a/test/libsolidity/syntaxTests/nameAndTypeResolution/233_non_initialized_references.sol +++ b/test/libsolidity/syntaxTests/nameAndTypeResolution/233_non_initialized_references.sol @@ -8,4 +8,4 @@ contract C { } } // ---- -// Warning: (84-95): Uninitialized storage pointer. +// DeclarationError: (84-95): Uninitialized storage pointer. diff --git a/test/libsolidity/syntaxTests/nameAndTypeResolution/234_non_initialized_references_050.sol b/test/libsolidity/syntaxTests/nameAndTypeResolution/234_non_initialized_references_050.sol deleted file mode 100644 index c221b73c..00000000 --- a/test/libsolidity/syntaxTests/nameAndTypeResolution/234_non_initialized_references_050.sol +++ /dev/null @@ -1,11 +0,0 @@ -pragma experimental "v0.5.0"; -contract C { - struct s { - uint a; - } - function f() public { - s storage x; - } -} -// ---- -// DeclarationError: (114-125): Uninitialized storage pointer. diff --git a/test/libsolidity/syntaxTests/parsing/arrays_in_expressions.sol b/test/libsolidity/syntaxTests/parsing/arrays_in_expressions.sol index 95ef66d4..2b35ffda 100644 --- a/test/libsolidity/syntaxTests/parsing/arrays_in_expressions.sol +++ b/test/libsolidity/syntaxTests/parsing/arrays_in_expressions.sol @@ -5,4 +5,4 @@ contract c { // Warning: (39-46): Variable is declared as a storage pointer. Use an explicit "storage" keyword to silence this warning. // Warning: (52-67): Variable is declared as a storage pointer. Use an explicit "storage" keyword to silence this warning. // TypeError: (39-50): Type int_const 7 is not implicitly convertible to expected type contract c[10] storage pointer. -// Warning: (52-67): Uninitialized storage pointer. Did you mean '<type> memory x'? +// DeclarationError: (52-67): Uninitialized storage pointer. Did you mean '<type> memory x'? diff --git a/test/libsolidity/syntaxTests/parsing/location_specifiers_for_locals.sol b/test/libsolidity/syntaxTests/parsing/location_specifiers_for_locals.sol index e311dd96..38de7b1c 100644 --- a/test/libsolidity/syntaxTests/parsing/location_specifiers_for_locals.sol +++ b/test/libsolidity/syntaxTests/parsing/location_specifiers_for_locals.sol @@ -1,11 +1,9 @@ contract Foo { - function f() public { - uint[] storage x; + uint[] m_x; + function f() public view { + uint[] storage x = m_x; uint[] memory y; + x; y; } } // ---- -// Warning: (49-65): Uninitialized storage pointer. -// Warning: (49-65): Unused local variable. -// Warning: (75-90): Unused local variable. -// Warning: (19-97): Function state mutability can be restricted to pure |