feat: invoice return

[akshayitzme]

This PR adds the functionality for Sales and Purchase Return.

Invoice Return

• [x] Update Schemas for Invoice Return
• [x] Enable Invoice Return
• [x] Tests
• [x] Documentation: https://github.com/frappe/books_docs/pull/26

Workflow

_follows ERPNext's workflow_ | # | Qty | SINV Outstanding | Return Inv Outstanding | Paid Amt (Pay) | Paid Amt (Receive) | |---|---|---|---|---|---| | **Scenario 1: (F Payment, F Return, F Payment)** | | | | | | | Invoice created | 2 | 20 | 0 | 0 | 0 | | Payment created | 2 | 0 | 0 | 0 | 20 | | Return issued (Full) | 2 | 0 | -20 | 0 | 0 | | Payment created against Return | 2 | 0 | 0 | 20 | 0 | | | | | | | | | **Scenario 2: (F Payment, P Return, P Payment)** | | | | | | | Invoice created | 2 | 20 | 0 | 0 | 0 | | Payment created | 2 | 0 | 0 | 0 | 20 | | Return Issued (Partial) | 1 | 0 | -10 | 0 | 0 | | Payment created against Return | 1 | 0 | 0 | 10 | 0 | | | | | | | | | **Scenario 3: (N Payment, F Return)** | | | | | | | Invoice created | 2 | 20 | 0 | 0 | 0 | | Return Issued (Full) | 2 | 20 | -20 | 0 | 0 | (_**F payment**: Full Payment, **P Payment**: Partial Payment, **N Payment**: No Payment_)

[chaoxu]

Is there a timeline on when this can be merged? This is an essential requirement that is holding me back from adopting frappe book.

[akshayitzme]

Did a self review, LGTM

[mildred]

@akshayitzme When using your code on an existing database, I get an error:

SqliteError alter table Payment add column referenceType text not null - Cannot add a NOT NULL column with default value ...

[akshayitzme]

@akshayitzme When using your code on an existing database, I get an error:

SqliteError alter table Payment add column referenceType text not null - Cannot add a NOT NULL column with default value ...

Hi, Thanks for pointing this out. I haven't tried reproducing it yet.. will do it in the coming days and push fixes if needed.

[akshayitzme]

@akshayitzme When using your code on an existing database, I get an error:

SqliteError alter table Payment add column referenceType text not null - Cannot add a NOT NULL column with default value ...

fixed in #782