ADFA-4331: Decode opened plugin tabs off the main thread by fryanpan · Pull Request #1416 · appdevforall/CodeOnTheGo

fryanpan · 2026-06-18T11:39:49Z

Jira Ticket: https://appdevforall.atlassian.net/browse/ADFA-4331
Sentry Issue: https://appdevforall-inc-9p.sentry.io/issues/APPDEVFORALL-1J

Question

Looks like this file is part of AndroidIDE -- do we make changes here or upstream?

Reproduction Details

A main-thread / ANR-risk performance issue (not a crash). EditorHandlerActivity.restoreOpenedPluginTabs() read the cached-tabs JSON from SharedPreferences and ran Gson().fromJson(...) synchronously on the main thread during startup, stalling the UI.

Stack Trace

No exception (profiling issue). Suspect function:

Gson.fromJson(JsonReader, TypeToken): Object   — on the main thread (warm start)

(issue type: profile_json_decode_main_thread · device.class: low)

User Steps

User steps leading up to crash, based on Sentry breadcrumbs:

App warm-start with previously-open plugin tabs to restore; the tab-state JSON is decoded on the main thread during onStart, blocking the first frames. (Profiling aggregate; tagged to the startup transaction.)

Was able to reproduce in a unit test?

Yes.
RestorePluginTabsThreadTest (:app, Robolectric) pins Dispatchers.Main, invokes the real private restoreOpenedPluginTabs(), and captures the thread on which its pref write executes (via the EventBus PreferenceChangeEvent). Baseline: write thread == main (FAIL); branch: write thread == DefaultDispatcher-worker (off main). Mutation-sensitive: flipping the prod file flips red/green.

What Was Fixed

Move the pref read + Gson decode + clearing write into withContext(Dispatchers.IO/Default) inside lifecycleScope.launch; UI updates stay on Main.

Testing

:app:testV8DebugUnitTest --tests …RestorePluginTabsThreadTest → green (red on baseline). Local CodeRabbit review: no findings. Reviewer notes (local): remove the leftover println("PROBE: …") debug line in the test; the restore now races the sibling onStart reopen-files coroutine (serialized on Main, theoretical only).

Fixes APPDEVFORALL-1J

coderabbitai · 2026-06-19T11:18:38Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: d7093df1-0fb1-4f9b-a7b5-3cc727ebae7c

📥 Commits

Reviewing files that changed from the base of the PR and between 0852a5e and 5585e97.

📒 Files selected for processing (2)

app/src/main/java/com/itsaky/androidide/activities/editor/EditorHandlerActivity.kt
app/src/test/java/com/itsaky/androidide/activities/editor/RestorePluginTabsThreadTest.kt

🚧 Files skipped from review as they are similar to previous changes (2)

app/src/main/java/com/itsaky/androidide/activities/editor/EditorHandlerActivity.kt
app/src/test/java/com/itsaky/androidide/activities/editor/RestorePluginTabsThreadTest.kt

📝 Walkthrough

Moved EditorHandlerActivity.restoreOpenedPluginTabs() work off the main thread during app startup by wrapping SharedPreferences access, JSON decoding, and cache clearing in coroutine background dispatchers.
Kept UI-facing tab selection/state updates within the launched coroutine flow, preserving behavior while reducing main-thread blocking and ANR risk.
Added a Robolectric regression test that verifies the cached-tabs preference is cleared from a background thread rather than the main test thread.
Risk: the change relies on coroutine dispatcher behavior and lifecycle timing during startup, so regressions could surface if the restore flow races with activity teardown or UI initialization.
Risk: review noted a possible collision with another in-flight PR, so merge conflicts or overlapping behavior changes should be checked carefully.

Walkthrough

restoreOpenedPluginTabs() now runs cached preference loading, JSON parsing, and cache clearing through coroutines instead of a single synchronous flow. A Robolectric regression test verifies the preference-clearing write occurs off the main thread.

Changes

Async plugin tab restore with threading regression test

Layer / File(s)	Summary
Async restore implementation and threading regression test `app/src/main/java/com/itsaky/androidide/activities/editor/EditorHandlerActivity.kt`, `app/src/test/java/com/itsaky/androidide/activities/editor/RestorePluginTabsThreadTest.kt`	`restoreOpenedPluginTabs` launches coroutine work to read `PREF_KEY_OPEN_PLUGIN_TABS` on `Dispatchers.IO`, parse JSON on `Dispatchers.Default`, restore tabs from the decoded IDs, and clear the cached preference key asynchronously. The Robolectric test seeds the cached JSON, preloads `pluginTabIndices` via reflection, invokes the private restore method, waits on an EventBus-backed latch, and asserts the preference-clearing write happens off the main/test thread.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

appdevforall/CodeOnTheGo#853: Introduced the EditorHandlerActivity.restoreOpenedPluginTabs() preference restore flow and the PREF_KEY_OPEN_PLUGIN_TABS persistence path that this PR changes.
appdevforall/CodeOnTheGo#952: Also touches EditorHandlerActivity lifecycle/threading safeguards around editor-side async work and tab handling.

Suggested reviewers

Daniel-ADFA
jomen-adfa

Poem

🐇 Hop to the IO lane, off the UI track,
JSON decodes, then the tabs hop back.
A latch in the burrow, a thread check at night,
Coroutines carry the cache out of sight.

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main change: moving opened plugin tab decoding off the main thread.
Description check	✅ Passed	The description matches the PR and explains the startup performance fix and regression test.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

Create stacked PR
Commit on current branch

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch ADFA-4331-restoreplugintabs-json-main-thread

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_{Comment @coderabbitai help to get the list of available commands.}

Sentry APPDEVFORALL-1J. Move Gson decode in restoreOpenedPluginTabs to Dispatchers.Default; keep UI updates on main. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

…in thread Failing-first repro that invokes the real private restoreOpenedPluginTabs() under Robolectric and captures the thread on which the cached-tabs preference write executes (via the EventBus PreferenceChangeEvent posted by PreferenceManager.putString). UI tab-selection is skipped by pre-seeding the private pluginTabIndices map. Pre-fix: read + Gson decode + clearing write run synchronously on the main thread -> write thread == main thread -> test FAILS. Fixed: read/decode/write are wrapped in withContext(Dispatchers.IO/Default) -> write runs on a background worker -> test PASSES. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

@test

Add KDoc to restoreOpenedPluginTabs() and the repro @test; remove a leftover println("PROBE: ...") debug line in RestorePluginTabsThreadTest. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

hal-eisen-adfa · 2026-06-20T05:57:45Z

Please be careful about possible collisions with PR #1426

fryanpan marked this pull request as ready for review June 19, 2026 11:15

fryanpan and others added 3 commits June 19, 2026 09:58

ADFA-4331: decode opened plugin tabs off the main thread

6514cf4

Sentry APPDEVFORALL-1J. Move Gson decode in restoreOpenedPluginTabs to Dispatchers.Default; keep UI updates on main. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

ADFA-4331: add KDoc for docstring coverage (CodeRabbit)

99467d1

Add KDoc to restoreOpenedPluginTabs() and the repro @test; remove a leftover println("PROBE: ...") debug line in RestorePluginTabsThreadTest. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

fryanpan force-pushed the ADFA-4331-restoreplugintabs-json-main-thread branch from 9d4f64c to 99467d1 Compare June 19, 2026 16:58

hal-eisen-adfa mentioned this pull request Jun 20, 2026

fix: Reset modified state when all changes are undone #1426

Open

jatezzz approved these changes Jun 23, 2026

View reviewed changes

Merge branch 'stage' into ADFA-4331-restoreplugintabs-json-main-thread

5585e97

Daniel-ADFA merged commit 97e5c06 into stage Jun 25, 2026
2 checks passed

Daniel-ADFA deleted the ADFA-4331-restoreplugintabs-json-main-thread branch June 25, 2026 14:45

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ADFA-4331: Decode opened plugin tabs off the main thread#1416

ADFA-4331: Decode opened plugin tabs off the main thread#1416
Daniel-ADFA merged 4 commits into
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ADFA-4331-restoreplugintabs-json-main-thread

fryanpan commented Jun 18, 2026 •

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coderabbitai Bot commented Jun 19, 2026 •

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hal-eisen-adfa commented Jun 20, 2026

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fryanpan commented Jun 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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fryanpan commented Jun 18, 2026 •

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coderabbitai Bot commented Jun 19, 2026 •

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