Mark message prefetch requests and let the server turn preloading off

[AndyScherzinger]

The rest of this series is merged — #6744 (modifiedSince delta sync), #6745 (periodic background refresh) and #6746 (foreground refresh loop) — so this one targets master and stands on its own.

The client fetches a conversation's messages before the user asks for them — after a push notification, and after a conversation list sync. On the wire those requests look exactly like the ones a user staring at a chat screen is waiting for, and the server has no way to say it would rather the client didn't make them at all.

Two commits, each answering one half of that, plus one unrelated note to AGENTS.md.

prefetch=1 on the requests the catch-up makes

A query parameter rather than a header, so it lands in a standard access log without any server configuration. Verified against a live server: the response is byte for byte the one sent without it, so the parameter is inert and purely descriptive.

The flag travels the same route as markNotificationsAsRead, which already separates these two cases, and defaults to false. The helpers that build the request are shared with the chat the user has open (OfflineFirstChatRepository calls buildFieldMap too), so a flag set any higher up would have labelled the messages someone is actively reading as prefetched — inverting the distinction this exists to draw. There is a test for exactly that.

The mobile-preload-chat capability

Implements the client side of spreed#19509. Preloading is skipped only when the server reports the setting as false. A server that reports true, one that omits it, and one too old to know it at all all preload — an operator cannot have declined something they were never offered.

Checked at both entry points, mirroring how chat-keep-notifications is already handled: the conversation list skips the whole catch-up rather than asking room by room, and the syncer checks it too, because push notifications reach it without passing the list.

AGENTS.md: spotting a test that asserts nothing

Separate from the feature, and in its own commit so it can be dropped without touching the rest. Review on this series found three tests that passed while never reaching the code they named — an earlier guard returned first, so the assertion was never evaluated, and running the suite cannot tell that apart from a test that works. The two habits that do catch it are now written down: check that a new test fails without its fix, and take the fixture from the code path while the assertion still comes from the requirement.

Scope

Only message preloading. The conversation list sync is not gated: the capability is about chat messages, and an operator turning message preloading off has not asked for unread counts to go stale.

🚧 TODO

• Verify the false path against a server that reports the capability — the test instance predates spreed#19509, so only the absent case could be exercised live

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not needed
• 🔖 Capability is checked or not needed
• 🔙 Backport requests are created or not needed: /backport to stable-xx.x
• 📅 Milestone is set
• 🌸 PR title is meaningful (if it should be in the changelog: is it meaningful to users?)

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI

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📝 Walkthrough

📝 Walkthrough

📝 Walkthrough

📝 Walkthrough

📝 Walkthrough

📝 Walkthrough

Walkthrough

Chat catch-up skips when the server lacks the chat-keep-notifications capability or explicitly disables mobile chat preloading. The preload check allows catch-up when the setting is absent. Catch-up requests can include prefetch=1, and the option propagates through initial, anchored, backlog, and fallback requests. Background room catch-up enables prefetch for delta and initial fetches. Tests cover request fields and preload settings.

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Priority: ⬇️ Low

Merge Risk: 🔵 Low · up to 56943

The change adds a prefetch marker and a server capability check for chat preloading. The remaining concern is a minor, previously raised race that could allow an unwanted room refresh, so the merge risk is low.

Pre-merge checks | 4 | 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 32.56% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 43 functions across 8 files. (1 skipped: …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.
Title check		The title clearly and concisely summarizes both main changes: marking message prefetch requests and allowing the server to disable preloading.
Description check		The description is detailed and covers the implementation, scope, testing, capability behavior, TODO, checklist, and AI usage. The screenshots section is omitted, but it is not critical for this backe…

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Full details: Docstring Coverage

Explanation

Docstring coverage is 32.56% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 43 functions across 8 files. (1 skipped: 1 unsupported.)

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📒 Files selected for processing (8)

• app/src/main/java/com/nextcloud/talk/chat/data/network/ChatMessageSyncer.kt
• app/src/main/java/com/nextcloud/talk/conversationlist/ConversationsListActivity.kt
• app/src/main/java/com/nextcloud/talk/conversationlist/data/OfflineConversationsRepository.kt
• app/src/main/java/com/nextcloud/talk/conversationlist/data/network/OfflineFirstConversationsRepository.kt
• app/src/main/java/com/nextcloud/talk/conversationlist/viewmodels/ConversationsListViewModel.kt
• app/src/main/java/com/nextcloud/talk/utils/CapabilitiesUtil.kt
• app/src/test/java/com/nextcloud/talk/chat/data/network/ChatMessageSyncerTest.kt
• app/src/test/java/com/nextcloud/talk/conversationlist/viewmodels/ConversationsListViewModelForegroundRefreshTest.kt

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⚠️ Outside diff range comments (1)

🟡 Minor · Assert prefetch for the never-opened-room request. · ChatMessageSyncerTest.kt:283-302

app/src/test/java/com/nextcloud/talk/chat/data/network/ChatMessageSyncerTest.kt:283-302
📐 Maintainability & Code Quality | 🟡 Minor | ⚡ Quick win

Assert prefetch for the never-opened-room request.

When newestMessageIdFromChatBlocks returns 0, catchUpRoom selects the background initialCatchUp path and passes prefetch = true. The request builder encodes this value as 1. This fixture captures that request but does not assert prefetch, so removing or mis-passing the argument would leave the test passing without its fix.

Suggested fix

             assertEquals(0, fieldMapCaptor.firstValue["markNotificationsAsRead"])
+            assertEquals(1, fieldMapCaptor.firstValue["prefetch"])

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Codacy

Lint

Type	master	PR
Warnings	138	138
Errors	15	15

SpotBugs

Category	Base	New
Bad practice	7	7
Correctness	11	11
Dodgy code	40	40
Internationalization	3	3
Malicious code vulnerability	3	3
Performance	8	8
Security	11	11
Total	83	83