Actually better to return zero on error.

This commit is contained in:
chriseth 2016-08-12 15:54:17 +02:00
parent 034d436933
commit d731225d02
4 changed files with 5 additions and 9 deletions

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@ -286,7 +286,7 @@ Global Variables
- ``sha3(...) returns (bytes32)``: compute the Ethereum-SHA-3 (KECCAK-256) hash of the (tightly packed) arguments
- ``sha256(...) returns (bytes32)``: compute the SHA-256 hash of the (tightly packed) arguments
- ``ripemd160(...) returns (bytes20)``: compute the RIPEMD-160 hash of the (tightly packed) arguments
- ``ecrecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) returns (address)``: recover address associated with the public key from elliptic curve signature
- ``ecrecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) returns (address)``: recover address associated with the public key from elliptic curve signature, return zero on error
- ``addmod(uint x, uint y, uint k) returns (uint)``: compute ``(x + y) % k`` where the addition is performed with arbitrary precision and does not wrap around at ``2**256``
- ``mulmod(uint x, uint y, uint k) returns (uint)``: compute ``(x * y) % k`` where the multiplication is performed with arbitrary precision and does not wrap around at ``2**256``
- ``this`` (current contract's type): the current contract, explicitly convertible to ``address``

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@ -95,7 +95,7 @@ Mathematical and Cryptographic Functions
``ripemd160(...) returns (bytes20)``:
compute RIPEMD-160 hash of the (tightly packed) arguments
``ecrecover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) returns (address)``:
recover the address associated with the public key from elliptic curve signature
recover the address associated with the public key from elliptic curve signature or return zero on error
In the above, "tightly packed" means that the arguments are concatenated without padding.
This means that the following are all identical::

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@ -1571,8 +1571,6 @@ void ExpressionCompiler::appendExternalFunctionCall(
m_context << u256(32);
utils().fetchFreeMemoryPointer();
m_context << Instruction::SUB << Instruction::MLOAD;
m_context << Instruction::DUP1 << Instruction::ISZERO;
m_context.appendConditionalJumpTo(m_context.errorTag());
}
else if (!_functionType.returnParameterTypes().empty())
{

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@ -6855,11 +6855,9 @@ BOOST_AUTO_TEST_CASE(create_dynamic_array_with_zero_length)
BOOST_AUTO_TEST_CASE(failing_ecrecover_invalid_input)
{
// ecrecover should throw for malformed input
// ecrecover should return zero for malformed input
// (v should be 27 or 28, not 1)
// This is quite hard to test because the precompiled does NOT throw, instead it just
// does not write to its output area, we have to check that and currently do it
// by checking whether ecrecover "returns" zero.
// Note that the precompile does not return zero but returns nothing.
char const* sourceCode = R"(
contract C {
function f() returns (address) {
@ -6868,7 +6866,7 @@ BOOST_AUTO_TEST_CASE(failing_ecrecover_invalid_input)
}
)";
compileAndRun(sourceCode, 0, "C");
BOOST_CHECK(callContractFunction("f()") == encodeArgs());
BOOST_CHECK(callContractFunction("f()") == encodeArgs(u256(0)));
}
BOOST_AUTO_TEST_SUITE_END()