fix(NegativeSampleGenerator): Prevent duplicate user IDs when getting unique IPs

[DerDreschner]

To weight the usage of IPs in the data model, the user id is being added multiple times to the dataset. The exact number is being determined here:

suspicious_login/lib/Service/DataLoader.php

Line 80 in 9043a66

$multiplier = (int)log((int)$addr->getSeen(), 2);

The problem is that this isn't always being taken into account when generating the training data. In case the dataset contains no IP with exactly one user id in the array, the array is malformed by containing only user ids (16 columns in size) in this variable:

suspicious_login/lib/Service/DataLoader.php

Line 107 in 9043a66

$shuffledNegatives = $this->negativeSampleGenerator->generateShuffledFromPositiveSamples($collectedData->getTrainingPositives(), $numShuffledNegative);

The reason is the code in the getUniqueIPsPerUser function. It returns only IPs with exactly one user id in the second dimension, while not checking if the user id was already added to the IP during the previous data transformation.

The Rubix ML library then throws an InvalidArgumentException due to the unequal number of columns when trying to merge the malformed array with the other datasets here:

suspicious_login/lib/Service/DataLoader.php

Line 115 in 9043a66

$allSamples = $collectedData->getTrainingPositives()->merge($randomNegatives)->merge($shuffledNegatives);

This PR will fix the issue and adds an unit test to prevent it during future refactoring steps.

Closes #860
Closes #933

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[solonovamax]

Is there anything major blocking this from being merged?

I've tested out these changes for myself, and it seems to fix #860.

[ChristophWurst]

Perfect, thanks for the descriptive PR and the test coverage 🙏

[DerDreschner]

@ChristophWurst : You're welcome! I'm looking forward to the release of my changes.

[ChristophWurst]

Dear @DerDreschner, apologies for the delay. It seems CI hasn't run so my attempt for automerge stalled. Let's try a branch update.

[joshtrichards]

/backport to stable30

[backportbot]

The backport to stable30 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable30
git pull origin stable30

# Create the new backport branch
git checkout -b backport/958/stable30

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick d1e2b79f cbe0fad3 2d894667 d4c332d3

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/958/stable30

Error: Failed to cherry pick commits: error: no cherry-pick or revert in progress
fatal: cherry-pick failed

---

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

[joshtrichards]

/backport to stable29

[backportbot]

The backport to stable29 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable29
git pull origin stable29

# Create the new backport branch
git checkout -b backport/958/stable29

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick d1e2b79f cbe0fad3 2d894667 d4c332d3

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/958/stable29

Error: Failed to cherry pick commits: error: no cherry-pick or revert in progress
fatal: cherry-pick failed

---

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

[DerDreschner]

@ChristophWurst / @joshtrichards : Looks something got very wrong. Backporting didn't work at all and I can't see my changes in the stable30 nor stable29 branch / 30.0.5rc1 tag.

[ChristophWurst]

Apologies for the delay, @DerDreschner. The bot failed because of the squashed merge. It probably tried to find the original commit hashes.
You can find the backport at #969. Please give it a review.