POC: New beresp.error VCL variable #4097
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All call sites pass the STRINGS type, so we can inline it directly.
This otherwise fails on a technicality that suggests the original intent
was to allow such a comparison:
Comparison of different types: STRING '==' STRING
The STRANDS <cmp> STRING comparison is denied with a different error
message.
For now it is a mere string, but having a dedicated ERROR type leaves the door open to properties (eg. error.foo.errno) in the future. Error symbols are constants, not variables, but reuse the vcl-var.7 codegen infrastructure.
The same should probably be done for resp in vcl_synth. The error field can be null, meaning there was either no error, or none was reported. There could be a catch-all "Unknown error" in the FSM and a respective error.unknown constant in VCL. Considerations like return(retry) not addressed.
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Bugwash summary:
Then we reevaluate the error reporting. |
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Following several VDD discussions, this patch series shows how getting a backend error could look like in VCL, and how it could be articulated in the core code.
This should check the boxes from the last consensus:
beresp.error)error.*)The first two commits are unrelated, I found a bug in libvcc while I was working on this. I will submit a pull request once I'm done with that bug (only partly fixed here) so the relevant commits to review are the ones starting with "POC".
If we still have consensus on this approach, I will find someone™ to submit something comprehensive.