fix voc07+12 training

[Nioolek]

Thanks for your contribution and we appreciate it a lot. The following instructions would make your pull request more healthy and more easily get feedback. If you do not understand some items, don't worry, just make the pull request and seek help from maintainers.

Motivation

Fixed an issue where VOC07 +12 dataset could not be trained. ConcatDataset in mmengine judge whether datasets metainfo is equal. VOC07 DATASET_TYPE is VOC2007, but VOC12 DATASET_TYPE is VOC2012. This resulted in an inability to train when using the VOC07+12 dataset:

Modification

Methods:

• add def metainfo(self) in VOCDataset to delete DATASET_TYPE.
• Dont judge and warn in voc_metric.py

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects, like MMDet or MMCls.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[CLAassistant]

All committers have signed the CLA.

[BIGWangYuDong]

@Nioolek Thanks for your contribution, Please remember to sign the CLA first.

[BIGWangYuDong]

Kindly ping @HAOCHENYE have a look, maybe we can add ignore_key in ConcatDataset to avoid this error

[ZwwWayne]

Hi @Nioolek ,

Thanks for your kind PR. It seems that your branch is out of date and causes much difference.

Now, we require all the PRs to be merged into the development branch, i.e., dev branch for MMDet 2.x and dev-3.x branch for MMDet 3.x.

If your modification is not checkout from these two branches, they may cause conflicts and you should add your modification based on these two branches.

If your modification is checkout from these two branches, your branch might be out of date. In such a case Please rebase your branch to the target dev or dev-3.x branch. You can simply do that by modifying your pull behavior:

git config --local --add pull.rebase true  # make rebase a default behavior in pull

Then you can git pull and rebase the dev branch by

git pull dev-3.x  # if your modification is for MMDet 3.x
git pull dev  # if your modification is for MMDet 2.x

After rebase, you might need to add --force option when pushing code, e.g.,

git push [remote name] [you branch] --force

[ZwwWayne]

Since the issue will be resolved in MMEngine, this PR is closed.