chore(code): github branch picker loading all branches

[VojtechBartos]

Problem

The branches API was capped at 2000 branches. Repositories with more than that were missing branches in the selector.

Changes

• Paginate the branches API call with offset/limit, fetching all pages progressively
• Show the first page of branches immediately while the rest load in the background
• Display a "Loading more" indicator with running count in the branch dropdown
• Show a spinner on the branch selector trigger while pages are still loading
• Disable the branch selector until the first page arrives

Prerequisite

Posthog API changes PostHog/posthog#53931

Showcase

code-paginating.branches.mov

[adboio]

i don't think it's your fault haha i'm just curious - where is that latency coming from? looked like at least a few seconds before we got the first page of results - is that posthog api or github api taking so long?

can be a followup, but if there's no way around that, we should consider some local caching here so it's snappier most of the time

[adboio]

can we abort this query once the user selects a branch?

or if we keep this and fetch everything even after the user is done, we should at least be caching the results (see global comment)

[VojtechBartos]

@adboio soooo :) ...

• we can fetch max 100 GH branches per page :(
• each page fetch takes ~400-500ms from my local, i hope it's going to be faster on prod, bud still
• for each page we were fetching default branch, not efficient

the changes i have made

• Posthog Code
  • we fetch first page with limit 100 so it's disabled fast and rest with limit 1000
  • we won't show spinner once collapsed
  • we will show only spinner when expanded
  • when you close/choose branch we pause fetching and resume when you open it again
  • changed query data stale time to default 5mins
• Posthog Backend
  • added caching for the fetching default branch (we can add branches fetching at some point in future if it's really pain)

WDYT?