Error when creating sales on Dashboard 2.0

[khalibloo]

What I'm trying to achieve

Create sales.

Steps to reproduce the problem

1. Fill in the sales creation form
2. Click submit

What I expected to happen

To have my sale created. Instead, I got an error message saying something went wrong. I checked the network response and I found the following error message from GraphQL. Variable "$input" got invalid value {"endDate": "2019-07-25", "name": "Winter Sale", "startDate": "2019-07-18", "type": "FIXED", "value": "15"}. In field "startDate": Expected type "DateTime", found "2019-07-18". In field "endDate": Expected type "DateTime", found "2019-07-25".

System information
Operating system: Windows 10 x64
Browser: Firefox 67

[khalibloo]

It appears that the graphql wants the dates in the following format 2019-07-15T00:00:00+00:00. Adding that in my query fixes the bug. This raises something interesting. To programmers, it's normal that when we have a start and end, the start is inclusive and the end is exclusive. Normal people don't work that way, I believe. Are the end dates in saleor inclusive? If the saleor dates use midnight time like above, that would make them exclusive.

[maarcingebala]

Related PR saleor/saleor#4539