fix: use primary key for link lookup

[dj12djdjs]

Overview

The stock balance report uses the tabItem.item_code column as a lookup for it's item filter. This differs from the expected name column used as lookup.

Context

The item has a name of 597f38b5c1 and an item_code of Demo Item

Before PR

After PR

[codecov]

Codecov Report

Merging #36919 (a29f54d) into develop (0e51722) will increase coverage by 0.12%.
Report is 8 commits behind head on develop.
The diff coverage is 66.66%.

@@             Coverage Diff             @@
##           develop   #36919      +/-   ##
===========================================
+ Coverage    65.42%   65.54%   +0.12%     
===========================================
  Files          794      795       +1     
  Lines        62194    62642     +448     
===========================================
+ Hits         40690    41059     +369     
- Misses       21504    21583      +79     

Files Changed	Coverage
...rpnext/stock/report/stock_balance/stock_balance.py	66.66%

[ankush]

When do item_code and name differ for item? They are supposed to be always same.

The change is okay, but just wondering.

[dj12djdjs]

@ankush In hindsight it is because of a flaw in my design for a customers customization.

The request was the make Item a two column lookup. Brand and Item Code, so these two columns are representing a unique record. Due to this customization, name becomes a random hash, and item_code becomes the sku.
You can see this customization in action here: frappe/frappe#21255

I should have have used item naming based on naming series, then used Brand, and Item Name as the unique record lookup. But I already made the customization. As far as I know this is the only function where my customization doesn't work.