fix(files): extract extension from basename in ObjectStoreStorage::fopen

[Bytepie]

Summary

Fixes an issue in ObjectStoreStorage::fopen() where the file extension is extracted using strrpos($path, '.') across the entire relative path instead of basename($path).

Problem

When an extensionless file is located inside a folder containing a dot (e.g. 0. Projects/Subfolder/hit), $ext is assigned the entire subpath string after the dot:

$ext = ". Projects/Subfolder/hit"

When TempManager::getTemporaryFile($ext) is called, directory separators are stripped:

/tmp/oc_tmp_<32_chars>. ProjectsSubfolderhit

Solution

1. Use basename($path) when extracting the file extension

Tests

Tested against live Nextcloud container where I had this issue during migration of data from GlusterFS to S3 (Ceph), and verified with PHPUnit in nextcloud-docker-dev environment.

• [Backports requested]

AI (if applicable)

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

[icewind1991]

As per our AI Policy, the PR description needs to be human written, which this does not appear to be. So I'm closing this issue for violating the policy.

If this is not the case, feel free to re-open.

[github-actions]

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[Bytepie]

Hi, @icewind1991 , I have made the PR again with only what I wrote. I couldn't open this one may be I don't have permission.
64770.

Kindly review it again. I spent good amount of time to work on this issue and in trying to contribute it into nextcloud/server for the first time. :)