Why is an empty 'name' allowed?

[tschmidtb51]

Congratulations to publishing the PURL spec.
I was made aware that the PURL spec has a generic regex for PURL in 6.10: ^pkg:[a-z][a-z0-9-\.]+/.*$
However, I'm a bit confused why an empty name in PURL is valid (instead of ^pkg:[a-z][a-z0-9-\.]+/.+$ which would require the name to be at least one character.)

Any insights are appreciated.

[mjherzog]

Hello @tschmidtb51 I do not understand your concern.

• Section 6.10 covers examples, not the core spec
• The name component is always required
  Where do you see evidence that the Core Spec allows an empty name component in a PURL?

[tschmidtb51]

Let me try to explain:
As far as I understood from your comment, there is no official PURL core spec regex.
The regex in section 6.10 just covers examples.

But then the questions arise: Why are empty names allowed in the examples? And why does a type have to have two characters in the examples?

For CSAF, I changed our JSON pattern for PURLs to "pattern": "^pkg:[a-z][a-z0-9\\.\\-]*\\/.+" (Hint: \ must be escaped with \ in JSON, and \ escapes special characters in regex.)
So, I was wondering whether I missed something when designing the PURL regex in CSAF as it differs from the one given in section 6.10.

[mjherzog]

Thank you for the clarification. I am far from a regex expert, but I do recall that during the final stages of preparing the PURL spec for submission to Ecma we discussed standardizing regex for PURL and decided that it was premature at that time. I doubt that you are missing anything with your implementation for CSAF. We should raise an issue to review and improve the handling regex for PURL including improvements to Section 6.10.