[shivamhwp]

Unproven: Return with a CJK IME on a hardware keyboard. I expect the IME to consume Return to confirm its composition before the composer sees it, but I had no CJK keyboard to try.

Problem

On Android with a hardware keyboard, Return always inserts a new line in the composer and no key sends. Tablet users have to reach for the screen to send every message.

Change

The Android composer now handles hardware Return the same way iOS does, with Ctrl in place of Command:

• Return key set to Send message (default): Return sends, Shift+Return inserts a new line, Ctrl+Return sends the other way (queue vs steer).
• Return key set to Insert new line: Return inserts a new line, Ctrl+Return sends, Ctrl+Shift+Return sends the other way.
• Only Return from a physical typing keyboard sends: the event has to come from a real, non-virtual alphabetic keyboard. An on-screen keyboard's Return inserts a new line, including an IME key event sent without the soft-keyboard flag. A held Return sends once.

The JS side (the Return key preference and onSubmit(alternate)) already existed for iOS. This adds the missing native piece: an enterBehavior prop, a submitEnabled prop and an onComposerSubmit event on the Android view. Settings → Keyboard was iOS-only, so it now shows on Android too, with "Ctrl-Return" in its text.

This is the composer part of #15030, taken without its iOS Expo patch work or the Android app-wide Ctrl shortcuts, so it can ship and be tested on its own. Credit to @t3dotgg for the original implementation and its Robolectric tests.

Scope and approval

Closes #21685. iOS already has this behavior and setting; this brings Android to parity.

Verification

Tested on a POCO F4 (Android 14) with a hardware keyboard. The "before" is internal nightly 147 (current main). The "after" is a dev client built from this branch on GitHub Actions, with JS from this branch. I couldn't download the EAS preview APK without an Expo login.

Before (main)	After
Return adds a new line and Ctrl+Return does nothing. video	Shift+Return adds a new line, then Return sends. video

The "Sends on reconnect" label is because that dev client was still reconnecting to its saved environments; it is the normal queued-send path, the same one the send button takes.

Settings → Keyboard on Android	"Insert new line" mode	On-screen keyboard
Shows on Android, with Ctrl in the text.	Return adds a new line, Ctrl+Return sends. video	Its Return key still adds a new line.

The "Insert new line" recording and a final Return send were re-run on the last commit's build.

• tsc-rs --noEmit in apps/mobile passes. ktlint 1.8.0 and detekt pass on the changed Kotlin files, and CI's Mobile Native Static Analysis passes.
• A disabled composer never sends. There's no composing-text guard like iOS's marked-text check: this phone's keyboard keeps a composing region over the last word even during hardware typing, and with that guard Ctrl+Return did nothing (tried on the device). An IME that confirms a composition with Return is expected to consume the key before the view sees it (see Unproven above).
• The composer's Robolectric tests (ComposerSubmitTest plus the existing paste and placeholder tests) pass on the latest commit: ./gradlew :t3-composer-editor:testDebugUnitTest on GitHub Actions, run. They cover the alternate send (Ctrl+Return in "Send message" mode, Ctrl+Shift+Return in "Insert new line" mode), a held Return sending once, and Return from anything but a physical keyboard: the virtual keyboard, device ID 0 when it's a non-alphabetic device, an unknown device, and an event with the soft-keyboard flag.

Physical-keyboard check (a68cd86)

Android lets an IME send Return with device ID 0 and no soft-keyboard flag, which the first version treated as hardware. Return now sends only when the event resolves to a non-virtual alphabetic keyboard. Device ID 0 isn't proof either: Android maps it to the built-in keyboard, which on these phones is the fingerprint sensor.

Tested on a POCO M3 Pro (Android 13) with a dev client built from this commit on GitHub Actions. The physical keyboard is the agentos uinput keyboard; Android reports it as external and alphabetic, the same as a USB keyboard.

"Send message" mode	"Insert new line" mode
Gboard's Return inserts a new line, hardware Return sends, Shift+Return inserts a new line. video	Hardware Return and Gboard's Return insert new lines, Ctrl+Return sends. video, setting

Limits: a standalone numeric keypad (non-alphabetic) can't send with Return, and on a device whose built-in keyboard really is alphabetic, an unflagged IME event with ID 0 would still send. I couldn't reproduce the original bad send on a real phone: Gboard's Return already inserted a new line on the previous build. adb shell input keyevent is blocked on this Xiaomi phone, so the virtual-keyboard case is covered by the Robolectric test only.

Created with Claude Opus 5.5 in Claude Code, running in T3 Code.

🤖 Generated with Claude Code

[macroscopeapp]

Approvability

Verdict: Needs Human Approval

Macroscope's review found this PR requires human approval — This PR changes Android’s production composer behavior and applies the existing send default to hardware-keyboard Return, while also adding a native event bridge and Android settings exposure. It additionally introduces a static-analysis suppression, so human review is warranted.

^{You can add or adjust custom eligibility rules. Learn more.}

[github-actions]

🚀 Expo continuous deployment is ready!

• Project → t3-code
• Platforms → android, ios
• Scheme → t3code-preview

	🤖 Android	🍎 iOS
Fingerprint	3755140c9e6edc587fe55622b251c0281f7fcab1	40749ec938f28df33d81dd1144b40806c0ffbbba
Build Details	Build Permalink Details Distribution: INTERNAL Build profile: preview:dev Runtime version: 3755140c9e6edc587fe55622b251c0281f7fcab1 App version: 2.0.0 Git commit: ec9cbf9ee3b3b6a77d8acbc43cc600a73ec3b9c9	Build Permalink Details Distribution: INTERNAL Build profile: preview:dev Runtime version: 40749ec938f28df33d81dd1144b40806c0ffbbba App version: 2.0.0 Git commit: 685b8e3530f6867d5c6e37b639c8df0a61d098ec
Update Details	Update Permalink Details Branch: pr-21687 Runtime version: 3755140c9e6edc587fe55622b251c0281f7fcab1 Git commit: ec9cbf9ee3b3b6a77d8acbc43cc600a73ec3b9c9	Update Permalink Details Branch: pr-21687 Runtime version: 40749ec938f28df33d81dd1144b40806c0ffbbba Git commit: ec9cbf9ee3b3b6a77d8acbc43cc600a73ec3b9c9
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📒 Files selected for processing: 2

• apps/mobile/modules/t3-composer-editor/android/src/main/java/expo/modules/t3composereditor/T3ComposerEditorView.kt
• apps/mobile/modules/t3-composer-editor/android/src/test/java/expo/modules/t3composereditor/ComposerSubmitTest.kt

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📝 Walkthrough

Android hardware Return chords can submit messages through the native composer. The Keyboard setting is available on Android, and the keybindings documentation describes Android Return behavior.

Changes: Android composer submission

Layer / File(s)	Summary
Native submit contract apps/mobile/src/native/T3ComposerEditor.types.ts, apps/mobile/src/native/T3ComposerEditor.native.tsx, apps/mobile/modules/t3-composer-editor/android/src/main/java/expo/modules/t3composereditor/T3ComposerEditorModule.kt	The native composer passes Enter behavior and submission availability to Android. It forwards submit events and their alternate flag to onSubmit.
Android Return handling apps/mobile/modules/t3-composer-editor/android/src/main/java/expo/modules/t3composereditor/T3ComposerEditorView.kt, apps/mobile/modules/t3-composer-editor/android/src/test/java/expo/modules/t3composereditor/ComposerSubmitTest.kt	The Android editor handles configured hardware Return chords, excludes soft-keyboard input from submission, and consumes repeated send chords without repeating the callback. Tests cover chord behavior and cases where submission is unavailable.
Keyboard setting and documentation apps/mobile/src/features/settings/SettingsRouteScreen.tsx, apps/mobile/src/features/settings/SettingsKeyboardRouteScreen.tsx, docs/user/keybindings.md	The Keyboard setting appears on Android. Its description uses the platform send modifier. The documentation describes Android hardware and on-screen Return behavior.

Priority: ➖ Normal

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix · Severity of issue fixed: Medium

Sequence Diagram(s)

sequenceDiagram
  participant Keyboard as Hardware keyboard
  participant Editor as SelectionAwareEditText
  participant NativeEvent as onComposerSubmit
  participant Composer as T3ComposerEditor.native
  participant Callback as onSubmit
  Keyboard->>Editor: Send Return chord
  Editor->>NativeEvent: Dispatch alternate flag
  NativeEvent->>Composer: Forward native submit event
  Composer->>Callback: Call with alternate flag

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Merge Risk: ⚪ Minimal · up to a68cd

Android hardware Return now follows the selected Keyboard setting. No actionable merge-blocking issue was established.

Security architecture risk: 🔵 Low · up to a68cd

The new keyboard action uses the existing message-send path, with safeguards against unavailable callbacks and held-key repetition. No security bypass was established. Composition-confirmation behavior and delayed events during navigation remain unverified.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The demonstrated reachability expansion is local keyboard input into the existing selected-thread send flow. The inspected changes do not add a direct native service call, target-identity selector, credential path, or new service authority. Downstream authorization enforcement was not fully inspected.

Trust Boundaries and Controls

• observed — Submission requires an enabled, editable editor, an available listener, and submission enablement. Input must lack the soft-keyboard flag and resolve to a non-virtual alphabetic device. Context import also removes the JavaScript callback and makes the editor read-only. Device metadata classifies input; it does not establish resistance to privileged local event injection.

Resilience and Maintainability Implications

• observed — The Android implementation deliberately omits a composing-text guard and expects an IME to consume composition-confirming Return before the view receives it. The composing-region test directly invokes the view using synthetic spans, so it does not establish real CJK IME dispatch behavior. This is an unresolved runtime assumption, not a demonstrated unintended-send vulnerability.

Pre-merge checks: 4

Check name	Status	Explanation
Title check		The title clearly and concisely describes the main change: Android hardware-keyboard Return now submits messages.
Linked Issues check		The Android composer implements the [#21685] hardware-keyboard send shortcut. In T3ComposerEditorView, physical non-virtual alphabetic Return submits according to the existing Return-key preference.…
Out of Scope Changes check		The changes stay within [#21685]. Native composer handling, the JavaScript bridge, Android Keyboard settings, user documentation, and focused Robolectric tests support the hardware-keyboard send featu…
Description check		The description includes the required Problem, Change, Scope and approval, and Verification sections. It explains expected behavior, implementation scope, linked issue, device testing, automated tests…

Full details: Linked Issues check

Explanation

The Android composer implements the [#21685] hardware-keyboard send shortcut. In T3ComposerEditorView, physical non-virtual alphabetic Return submits according to the existing Return-key preference. Shift+Return inserts a newline in send mode. Ctrl+Return provides the normal or alternate submit path in both modes. Virtual, unknown, non-alphabetic, and soft-keyboard events insert a newline. ComposerSubmitTest covers these paths, disabled editors, unavailable submission, and held Return. Android Settings exposes the existing Keyboard preference and uses the Ctrl label.

Full details: Out of Scope Changes check

Explanation

The changes stay within [#21685]. Native composer handling, the JavaScript bridge, Android Keyboard settings, user documentation, and focused Robolectric tests support the hardware-keyboard send feature. The provided scope excludes unrelated app-wide Android shortcuts and iOS Expo work, and the changes do not add those features.

Full details: Description check

Explanation

The description includes the required Problem, Change, Scope and approval, and Verification sections. It explains expected behavior, implementation scope, linked issue, device testing, automated tests, screenshots, recordings, limitations, and agent attribution.

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@apps/mobile/modules/t3-composer-editor/android/src/main/java/expo/modules/t3composereditor/T3ComposerEditorView.kt:
- Around line 684-685: Update submitChord to extract the composing-state and
submission-eligibility checks into a helper, reducing its complexity below
detekt’s limit while preserving the existing Return behavior.

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@apps/mobile/modules/t3-composer-editor/android/src/main/java/expo/modules/t3composereditor/T3ComposerEditorView.kt:
- Around line 691-693: Update isFromSoftKeyboard and the hardware Return
handling to require positive evidence of a resolved physical keyboard device
before submitting, rather than treating events without soft-keyboard indicators
as hardware. Preserve newline insertion for ambiguous events, and add a
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