[tarantool-patches] Re: [PATCH 2/2] sql: don't change type of function's retval after codegen

[n.pettik]

> On 11/03/2019 21:10, Nikita Pettik wrote:
>> Proper type of function's returning value is set during names resolution
>> (i.e. promotion from struct FuncDef to struct Expr, see
>> resolveExprStep()). Accidentally, it was set again during byte-code
>> generation for VDBE. What is more, in some cases it was set to a wrong
>> type. For instance, built-in function randomblob() returns value to be
>> encoded as MP_BIN, so its returning type is SCALAR. However, it was
>> reset to INTEGER (as its first argument). This patch simply removes this
>> second type promotion.
>> ---
>>  src/box/sql/expr.c       | 11 -----------
>>  test/sql/iproto.result   | 41 +++++++++++++++++++++++++++++++++++++++++
>>  test/sql/iproto.test.lua | 15 +++++++++++++++
>>  3 files changed, 56 insertions(+), 11 deletions(-)
>> diff --git a/test/sql/iproto.result b/test/sql/iproto.result
>> index 3a77c8e93..26d55b60c 100644
>> --- a/test/sql/iproto.result
>> +++ b/test/sql/iproto.result
>> +-- Type set during compilation stage, and since min/max are accept
>> +-- arguments of all scalar type, we can't say nothing more than
>> +-- SCALAR.
>> +--
>> +cn:execute("SELECT min(1, 2, 3);")
>> +---
>> +- metadata:
>> +  - name: min(1, 2, 3)
>> +    type: scalar
> 
> This is the case, when a first argument type would be ok. As I
> understand, it is illegal to calculate min of multiple different
> types, so its rettype should be equal to its first argument. It
> is not?

Unfortunately, it is legal:

tarantool> SELECT min('abc', 1);
---
- - [1]
…

It is to be resolved in scope of this issue:
https://github.com/tarantool/tarantool/issues/4032