path: root/test/libsolidity/ViewPureChecker.cpp

/*
    This file is part of solidity.

    solidity is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    solidity is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with solidity.  If not, see <http://www.gnu.org/licenses/>.
*/
/**
 * Unit tests for the view and pure checker.
 */

#include <test/libsolidity/AnalysisFramework.h>

#include <test/Options.h>

#include <boost/test/unit_test.hpp>

#include <string>
#include <tuple>

using namespace std;

namespace dev
{
namespace solidity
{
namespace test
{

BOOST_FIXTURE_TEST_SUITE(ViewPureChecker, AnalysisFramework)

BOOST_AUTO_TEST_CASE(smoke_test)
{
    char const* text = R"(
        contract C {
            uint x;
            function g() pure public {}
            function f() view public returns (uint) { return now; }
            function h() public { x = 2; }
            function i() payable public { x = 2; }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(call_internal_functions_success)
{
    char const* text = R"(
        contract C {
            function g() pure public { g(); }
            function f() view public returns (uint) { f(); g(); }
            function h() public { h(); g(); f(); }
            function i() payable public { i(); h(); g(); f(); }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(suggest_pure)
{
    char const* text = R"(
        contract C {
            function g() view public { }
        }
    )";
    CHECK_WARNING(text, "can be restricted to pure");
}

BOOST_AUTO_TEST_CASE(suggest_view)
{
    char const* text = R"(
        contract C {
            uint x;
            function g() public returns (uint) { return x; }
        }
    )";
    CHECK_WARNING(text, "can be restricted to view");
}

BOOST_AUTO_TEST_CASE(call_internal_functions_fail)
{
    CHECK_ERROR(
        "contract C{ function f() pure public { g(); } function g() view public {} }",
        TypeError,
        "Function declared as pure, but this expression (potentially) reads from the environment or state and thus requires \"view\""
    );
}

BOOST_AUTO_TEST_CASE(write_storage_fail)
{
    CHECK_WARNING(
        "contract C{ uint x; function f() view public { x = 2; } }",
        "Function declared as view, but this expression (potentially) modifies the state and thus requires non-payable (the default) or payable."
    );
}

BOOST_AUTO_TEST_CASE(environment_access)
{
    vector<string> view{
        "block.coinbase",
        "block.timestamp",
        "block.blockhash(7)",
        "block.difficulty",
        "block.number",
        "block.gaslimit",
        "blockhash(7)",
        "gasleft()",
        "msg.gas",
        "msg.value",
        "msg.sender",
        "tx.origin",
        "tx.gasprice",
        "this",
        "address(1).balance"
    };
    // ``block.blockhash`` and ``blockhash`` are tested seperately below because their usage will
    // produce warnings that can't be handled in a generic way.
    vector<string> pure{
        "msg.data",
        "msg.data[0]",
        "msg.sig",
        "msg",
        "block",
        "tx"
    };
    for (string const& x: view)
    {
        CHECK_ERROR(
            "contract C { function f() pure public { " + x + "; } }",
            TypeError,
            "Function declared as pure, but this expression (potentially) reads from the environment or state and thus requires \"view\""
        );
    }
    for (string const& x: pure)
    {
        CHECK_WARNING(
            "contract C { function f() view public { " + x + "; } }",
            "Function state mutability can be restricted to pure"
        );
    }

    CHECK_WARNING_ALLOW_MULTI(
        "contract C { function f() view public { blockhash; } }",
        (std::vector<std::string>{
            "Function state mutability can be restricted to pure",
            "Statement has no effect."
    }));

    CHECK_WARNING_ALLOW_MULTI(
        "contract C { function f() view public { block.blockhash; } }",
        (std::vector<std::string>{
            "Function state mutability can be restricted to pure",
            "\"block.blockhash()\" has been deprecated in favor of \"blockhash()\""
    }));
}

BOOST_AUTO_TEST_CASE(view_error_for_050)
{
    CHECK_ERROR(
        "pragma experimental \"v0.5.0\"; contract C { uint x; function f() view public { x = 2; } }",
        TypeError,
        "Function declared as view, but this expression (potentially) modifies the state and thus requires non-payable (the default) or payable."
    );

}

BOOST_AUTO_TEST_CASE(modifiers)
{
    string text = R"(
        contract D {
            uint x;
            modifier purem(uint) { _; }
            modifier viewm(uint) { uint a = x; _; a; }
            modifier nonpayablem(uint) { x = 2; _; }
        }
        contract C is D {
            function f() purem(0) pure public {}
            function g() viewm(0) view public {}
            function h() nonpayablem(0) public {}
            function i() purem(x) view public {}
            function j() viewm(x) view public {}
            function k() nonpayablem(x) public {}
            function l() purem(x = 2) public {}
            function m() viewm(x = 2) public {}
            function n() nonpayablem(x = 2) public {}
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(interface)
{
    string text = R"(
        interface D {
            function f() view external;
        }
        contract C is D {
            function f() view external {}
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(overriding)
{
    string text = R"(
        contract D {
            uint x;
            function f() public { x = 2; }
        }
        contract C is D {
            function f() public {}
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(returning_structs)
{
    string text = R"(
        contract C {
            struct S { uint x; }
            S s;
            function f() view internal returns (S storage) {
                return s;
            }
            function g() public {
                f().x = 2;
            }
            function h() view public {
                f();
                f().x;
            }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(mappings)
{
    string text = R"(
        contract C {
            mapping(uint => uint) a;
            function f() view public {
                a;
            }
            function g() view public {
                a[2];
            }
            function h() public {
                a[2] = 3;
            }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(local_storage_variables)
{
    string text = R"(
        contract C {
            struct S { uint a; }
            S s;
            function f() view public {
                S storage x = s;
                x;
            }
            function g() view public {
                S storage x = s;
                x = s;
            }
            function i() public {
                s.a = 2;
            }
            function h() public {
                S storage x = s;
                x.a = 2;
            }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(builtin_functions)
{
    string text = R"(
        contract C {
            function f() public {
                address(this).transfer(1);
                require(address(this).send(2));
                selfdestruct(address(this));
                require(address(this).delegatecall());
                require(address(this).call());
            }
            function g() pure public {
                bytes32 x = keccak256("abc");
                bytes32 y = sha256("abc");
                address z = ecrecover(1, 2, 3, 4);
                require(true);
                assert(true);
                x; y; z;
            }
            function() payable public {}
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(function_types)
{
    string text = R"(
        contract C {
            function f() pure public {
                function () external nonpayFun;
                function () external view viewFun;
                function () external pure pureFun;

                nonpayFun;
                viewFun;
                pureFun;
                pureFun();
            }
            function g() view public {
                function () external view viewFun;

                viewFun();
            }
            function h() public {
                function () external nonpayFun;

                nonpayFun();
            }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(selector)
{
    string text = R"(
        contract C {
            uint public x;
            function f() payable public {
            }
            function g() pure public returns (bytes4) {
                return this.f.selector ^ this.x.selector;
            }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(selector_complex)
{
    string text = R"(
        contract C {
            function f(C c) pure public returns (C) {
                return c;
            }
            function g() pure public returns (bytes4) {
                // By passing `this`, we read from the state, even if f itself is pure.
                return f(this).f.selector;
            }
        }
    )";
    CHECK_ERROR(text, TypeError, "reads from the environment or state and thus requires \"view\"");
}

BOOST_AUTO_TEST_CASE(selector_complex2)
{
    string text = R"(
        contract C {
                function f() payable public returns (C) {
                return this;
            }
            function g() pure public returns (bytes4) {
                C x = C(0x123);
                return x.f.selector;
            }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(creation)
{
    string text = R"(
        contract D {}
        contract C {
            function f() public { new D(); }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(assembly)
{
    string text = R"(
        contract C {
            struct S { uint x; }
            S s;
            function e() pure public {
                assembly { mstore(keccak256(0, 20), mul(s_slot, 2)) }
            }
            function f() pure public {
                uint x;
                assembly { x := 7 }
            }
            function g() view public {
                assembly { for {} 1 { pop(sload(0)) } { } pop(gas) }
            }
            function h() view public {
                assembly { function g() { pop(blockhash(20)) } }
            }
            function j() public {
                assembly { pop(call(0, 1, 2, 3, 4, 5, 6)) }
            }
            function k() public {
                assembly { pop(call(gas, 1, 2, 3, 4, 5, 6)) }
            }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(assembly_staticcall)
{
    string text = R"(
        contract C {
            function i() view public {
                assembly { pop(staticcall(gas, 1, 2, 3, 4, 5)) }
            }
        }
    )";
    if (!dev::test::Options::get().evmVersion().hasStaticCall())
        CHECK_WARNING(text, "\"staticcall\" instruction is only available for Byzantium-compatible");
    else
        CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_CASE(assembly_jump)
{
    string text = R"(
        contract C {
            function k() public {
                assembly { jump(2) }
            }
        }
    )";
    CHECK_WARNING(text, "low-level EVM features");
}

BOOST_AUTO_TEST_CASE(constant)
{
    string text = R"(
        contract C {
            uint constant x = 2;
            function k() pure public returns (uint) {
                return x;
            }
        }
    )";
    CHECK_SUCCESS_NO_WARNINGS(text);
}

BOOST_AUTO_TEST_SUITE_END()

}
}
}