Loose BigQuery GCP project ID regex restrictions

[kberezin-nshl]

This addresses #32168, please see rationale there

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[kberezin-nshl]

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[kberezin-nshl]

There is probably a test flake?

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[Abacn]

I agree this is a reasonable change. Checked that PROJECT_ID_REGEXP is only used for extracting projectid/dataset/table from a table reference or table urn, it is not used in validation purpose.

For this reason please preserve the original comments, but could say

Formally, project IDs must contain 6-63 lowercase letters, ...

then

This regex is used for for basic parsing of table references rather than validation purpose, e.g. it allows looser restriction for testing on mock resources. It may allow for patterns that would be rejected by the service

[kberezin-nshl]

Thanks @Abacn , I have adjusted the comment accordingly.

[Abacn]

I thought further about it, previously project id cannot ends with colon and dot, now it does not guard against it. I cannot tell if this could have unexpected results. Consider use [a-z][-a-z0-9:.]{0,61}[a-z0-9] ? then effectively it still requires project id of at least 2 chars

[kberezin-nshl]

Well, previously project ID couldn't have less than 5 symbols either 😄 I think that's the point of the change, enforcing somebody else's rules shouldn't be a concern of 3rd party library, which Apache Beam is.

Having said that, I made the requested change because I think "at least 2 chars long" is a reasonable restriction.

We really hope this change will make it into 2.59.0!

[kberezin-nshl]

Could you please have a look again, @Abacn ?

[Abacn]

It passed the 2.59.0 release cut unfortunately. You can try open a cherry pick PR to release-2.59.0 branch (similar to this one: #32290) and up to release manager cc: @lostluck available for cherry-pick