COW metadata / no metadata on metakeys

[kodebach]

Because metadata on meta keys is not allowed we can use Copy-On-Write semantics for metadata. Therefore all keys of the namespace KEY_NS_META should automatically have the flags KEY_FLAG_RO_NAME, KEY_FLAG_RO_VALUE and KEY_FLAG_RO_META set during keyVNew.

This ensures that keySetMeta will fail. It also avoids any problems with ksDeepDup (#3609), since the need for deep-copies of metadata is removed. Therefore keyDup (#3606) can just create a shallow-copy of the metadata without any further implications.

Additionally, KEY_NS_META keys should at all times fulfill key->meta == NULL and keyMeta() should return NULL instead of allocating a new KeySet.

[markus2330]

Thank you for reporting the problem! Actually the metakeys should be completely read-only, see #3609

[kodebach]

I updated the issue

[stale]

I mark this issue stale as it did not have any activity for one year. I'll close it in two weeks if no further activity occurs. If you want it to be alive again, ping the issue by writing a message here or create a new issue with the remainder of this issue.
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[kodebach]

@markus2330 This should probably be implemented together with the removal of keyGetMeta/keySetMeta.

[github-actions]

I mark this stale as it did not have any activity for one year. I'll close it in two weeks if no further activity occurs. If you want it to be alive again, ping by writing a message here or create a new issue with the remainder of this issue.
Thank you for your contributions 💖

[github-actions]

I closed this now because it has been inactive for more than one year. If I closed it by mistake, please do not hesitate to reopen it or create a new issue with the remainder of this issue.
Thank you for your contributions 💖

[kodebach]

See #4744

[github-actions]

I mark this stale as it did not have any activity for one year. I'll close it in two weeks if no further activity occurs. If you want it to be alive again, ping by writing a message here or create a new issue with the remainder of this issue.
Thank you for your contributions 💖

[github-actions]

I closed this now because it has been inactive for more than one year. If I closed it by mistake, please do not hesitate to reopen it or create a new issue with the remainder of this issue.
Thank you for your contributions 💖