Custom protocol reported as invalid
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- Dominant language
- Java
- Stars
- 250
- Forks
- 123
- PR merge metrics
- No merged PRs in 30d
Description
Originally reported to HTML validator https://github.com/validator/validator/issues/1949.
Steps to reproduce:
- Validate this code:
.foo { background: url("foo://example.com/image.svg"); }
Result:
Validation failed (Value Error : background url("foo://example.com/image.svg") is an incorrect URL url("foo://example.com/image.svg")
Expected:
Validation passed.
I did not find in HTML/CSS specification any rule which suggests that I can't use custom protocol.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the validation failure with the CSS snippet in this issue and trace how the validator checks the custom foo:// URL in the background declaration. Done means the snippet validates successfully without weakening validation for genuinely invalid URLs.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java
- Domain
- tooling
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 50/100