fix: item db duplicate handling is stable over insertion order

[BrknRobot]

Previously, the particular duplicate stored in the item db depended on insertion order.
Now, item Locs are compared during db insertion to ensure the stored entry is the last one in the load order.

The resulting reports should be stable in cases of a single duplicate. More than that may report duplicate differences in which location overwrote which, but always result in the correct final item overwriting all others

[amtep]

The insertion order is carefully controlled to override items in the right order. Do you have an example of where it's wrong? Because that needs to be looked at.

[BrknRobot]

I'm just noticing now that all the examples I have are tutorial steps. Not sure if that's due to an issue there specifically or if it's more broad, but vanilla doesn't have duplicates across files in other spots

Run 1

warning(duplicate-item): tutorial lesson step is redefined by another tutorial lesson step
    --> [CK3] common/tutorial_lessons/00_tutorial_lessons_reactive.txt
3557 |     lesson_war_final_notes_invalidated_step_1 = {
     |     ^ <-- from here
    --> [CK3] common/tutorial_lessons/00_tutorial_lessons_war.txt
 635 |     lesson_war_final_notes_invalidated_step_1 = {
     |     ^ <-- from here

Run 2

warning(duplicate-item): tutorial lesson step is redefined by another tutorial lesson step
    --> [CK3] common/tutorial_lessons/00_tutorial_lessons_war.txt
 635 |     lesson_war_final_notes_invalidated_step_1 = {
     |     ^ <-- from here
    --> [CK3] common/tutorial_lessons/00_tutorial_lessons_reactive.txt
3557 |     lesson_war_final_notes_invalidated_step_1 = {
     |     ^ <-- from here

Run 1

warning(exact-duplicate-item): tutorial lesson step is redefined by an identical tutorial lesson step
    --> [CK3] common/tutorial_lessons/00_tutorial_lessons_reactive.txt
3355 |     lesson_warscore_step_1 = {
     |     ^ <-- from here
    --> [CK3] common/tutorial_lessons/00_tutorial_lessons_war.txt
 400 |     lesson_warscore_step_1 = {
     |     ^ <-- from here

Run 2

warning(exact-duplicate-item): tutorial lesson step is redefined by an identical tutorial lesson step
    --> [CK3] common/tutorial_lessons/00_tutorial_lessons_war.txt
 400 |     lesson_warscore_step_1 = {
     |     ^ <-- from here
    --> [CK3] common/tutorial_lessons/00_tutorial_lessons_reactive.txt
3355 |     lesson_warscore_step_1 = {
     |     ^ <-- from here

[BrknRobot]

vic3 coat of arms and ck3 accessory variations have cross file duplicates but don't seem to be affected actually. I see coa has some custom logic for duplicates, but I'm not seeing why accessory variations are unaffected

[BrknRobot]

Possibly the difference is that tutorial steps get added as a subitem

[BrknRobot]

It seems that processing subitems in loc order stabilises the tutorial step duplicate reports
BrknRobot@bdfdd48

[amtep]

It seems that processing subitems in loc order stabilises the tutorial step duplicate reports BrknRobot@bdfdd48

Okay :)
I'd like to have both patches. Inserting in the correct order, but also making add forgiving of wrong order inserts. The latter is a step toward maybe parallelizing insertions.

But what do you think of doing the same for other users of dup_error? Every FileHandler has one.