rokucommunity / rokucommunity/brighterscript

Null coalescing operator used with namespace constant results in warning

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Dominant language
TypeScript
Stars
208
Forks
68
Avg merge
8h 39m
Merged PRs (30d)
39

Description

A pattern we have been using is to retrieve a value from a remote configuration, but fallback to a local constant if the remote value isn't defined.
For example:

url = m.config?.serviceUrls?.imageService ?? CommonConfigConst.imageServiceUrl

where CommonConfigConst.imageServiceUrl is defined as

namespace CommonConfigConst
    const imageServiceUrl = "https://<some server>/"
end namespace

The transpiler converts that to

url = (function(CommonConfigConst, m)
                __bsConsequent = m.config?.serviceUrls?.imageService
                if __bsConsequent <> invalid then
                    return __bsConsequent
                else
                    return "https://i<some server>/"
                end if
            end function)(CommonConfigConst, m)

When the channel is side loaded, we see a warning in the console:

BRIGHTSCRIPT: WARNING: unused variable 'commonconfigconst' in anonymous function in /<path to code>/ImageService.bs:62

It seems that the transpiler is inlining the constant, but treating the namespace as a variable.

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the shown null-coalescing expression with a namespace constant and inspect the transpiler path that generates the anonymous function. Confirm that the namespace is not treated as an unused variable while the constant fallback remains inlined, and verify that the warning no longer appears.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
compilers
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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