fix(updater): remove leftover installer during config version migration

[chrip]

Resolves

#7009

Summary

Every update leaves its installer (~200 MB) and msi.log behind in %APPDATA%\Nextcloud, one file per release.

#8980 did not take effect in practice. On the first start of a newly installed version, Application::configVersionMigration() calls ConfigFile::cleanUpdaterConfiguration() (application.cpp:161-164), which drops Updater/updateAvailable — the only record of where the installer is — before main() reaches NSISUpdater::handleStartup() (main.cpp:104 vs :142). Both wipeUpdateData() call sites then sit behind a guard that can no longer be true, and the file is orphaned with nothing left to find it by.

The trigger is the version number in nextcloud.cfg versus the one compiled into the running binary. They differ on every real update, and are identical when the same version is reinstalled — which is why this passes local testing, and why CI cannot express the case at all (one binary, one MIRALL_VERSION_STRING). It regressed in v3.16.0 with b3886ed (#7807); before that the main flow cleaned up correctly and only unusual paths leaked.

ConfigFile::cleanUpdaterConfiguration() now deletes the installer and msi.log before dropping the keys, and NSISUpdater::wipeUpdateData() delegates to it instead of duplicating the same four key removals. Startup ordering is untouched, so #7807's intent is preserved.

Deliberately not included: installers that have already accumulated (no recorded path remains, so they need a directory sweep) and the download location itself.

Tests

testLeftoverInstallerIsRemovedAfterVersionChange fails on master and passes with the fix.

	before	after
Windows, version change, real nextcloud.exe	Version changed… logged, no removal, both files survive	two Removed leftover updater file: lines, both files gone
Windows, pending update, no version change	untouched	untouched (must not regress)
Windows ctest	78/78	78/78
Linux ctest	79/79	79/79

All seven paths the updater can take were driven against the real binary — the five dialog outcomes ("New update ready" → Cancel / OK; "Update Failed" → Ask again later / Restart and update / Update manually) plus the two non-interactive ones (version change, external install).

Deletion happens only in the two cases where the update is genuinely finished, and in none of the five where a decision is still pending — a pending installer is never removed.

Built and verified on Windows (Craft/MSVC 2022) and Linux (Qt 6.10.2). Not tested: the locked-file case (QFile::remove failing under an antivirus or open handle), which logs a warning and leaves the file.

Checklist

• Sign-off message is added to all commits.
• The commit messages are following The Conventional Commits specification.
• The commit history is clean with no merge commits.
• Uploaded screenshots from before and after for UI changes. — no UI change
• Test(s) added to branch, with before/after results included in PR description.
• Documentation has been updated or is not required.
• Backports requested where applicable — stable-34.0, stable-33.0
• Labels added where applicable (bug/enhancement).
• Milestone added for target version.

AI (if applicable)

• The content of this PR was partly or fully generated using AI
  • I have read the guidelines for AI-assisted contributions.
  • I have read Nextcloud's AI Contribution Policy.

[mgallien]

thanks
one small change only

[github-actions]

Artifact containing the AppImage: nextcloud-appimage-pr-10680.zip

Digest: sha256:64f1095ef91cd992fb38e237794554640c4dd21843d02193f85a6a15568c4c75

To test this change/fix you can download the above artifact file, unzip it, and run it.

Please make sure to quit your existing Nextcloud app and backup your data.

[mgallien]

/backport to stable-34.0 please

[backportbot]

The backport to stable-34.0 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable-34.0
git pull origin stable-34.0

# Create the new backport branch
git checkout -b backport/10680/stable-34.0

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick d53bb2d7

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/10680/stable-34.0

Error: Failed to clone repository: Failed to create working tree: error: RPC failed; HTTP 401 curl 22 The requested URL returned error: 401
fatal: expected flush after ref listing

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Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.