Eos: print("\n") seems some wrong.when comes one print("\n"),the latter doesn't work.

[cophey]

void testbr(){
        print("test1\n");
        print("test2\n");
}

When call the contranct action,it only print test1.

[taokayan]

can you provide the output?

[damianoazzolini]

I've reproduced the same situation. I've an action called test structured in this way:

void test(account_name user) {
        print("print1\n");
        print("print2\n");
        print( "Hello, ", name{user} );
    }

I've created an account test and called the action cleos push action test test '["a"]' -p test. In the console with cleos i see

executed transaction: a5851c60516db247a9e73c64348db847875f05cbcca8ceb765443fc5f008ca2a  104 bytes  4284 us
#          test <= test::test                   {"user":"a"}
>> print1
warning: transaction executed locally, but may not be confirmed by the network yet    ]

so only the first print is printed. BTW, if a look at the console with nodeos running, i see all the data printed (i've the flag --contracts-console set in nodeos):

2018-09-14T08:35:10.960 thread-0   apply_context.cpp:28          print_debug          ]
[(test,test)->test]: CONSOLE OUTPUT BEGIN =====================
print1
print2
Hello, a
[(test,test)->test]: CONSOLE OUTPUT END   =====================

[heifner]

cleos only prints the first line. Add --verbose to your cleos for more output.

[damianoazzolini]

Even if i modify the command in cleos --verbose push action test test '["a"]' -p test the output is still the same. I think because the verbose flag works only if there is an error, as written in the helper: -v,--verbose output verbose actions on error

[heifner]

Yep, forgot that. Use --json to get full output.

[damianoazzolini]

Using cleos push action test test '["a"]' -p test --json i can get the result in json format "console": "print1\nprint2\nHello, a". So there is no way at the moment to print more than one line in cleos without print the whole json right?

[heifner]

Correct. cleos only prints the first line. We could add an option I suppose to print all lines. But at some point it is better to just output json and let the user format as desired.

[godmar]

An odd decision, especially given how many hours you steal from new developers who wonder whether their smart contract has the desired effect - or any effect at all.

I will note that EOS's own documentation recommends: _The main method used to debug smart contract is Caveman Debugging, where we utilize the printing functionality to inspect the value of a variable and check the flow of the contract. Printing in smart contract can be done through the Print API (C and C++). The C++ API is the wrapper for C API, so most often we will just use the C++ API._

[godmar]

For the benefit of any readers who may stumble on this issue, here's how I was able to work around this:

cleos push action -j ..... > output.json
jq -r '.processed.action_traces[].console' output.json 

using the jq utility.
If you're debugging an notify action, then it would be:

jq -r '.processed.action_traces[].inline_traces[].console' output.json