Is it safe to modify a build instance after calling Complete()?

[cueckoo]

Originally opened by @shykes in cuelang/cue#445

I am trying to implement a custom dependency fetcher. Given a build.Instance, I want to detect its unresolved dependencies, and if possible, resolve them.

I found a possible solution, but would like to confirm that it is safe and uses the API correctly:

import (
  cueBuild "cuelang.org/go/cue/build"
)

func resolveImports(buildInst *cueBuild.Instance) (err error) {
  // Call Complete()
  err = buildInst.Complete()
  if err != nil {
    return
  }
  // Iterate on detected imports
  for _, importPath := range buildInst.ImportPaths {
    // Custom dependency fetching here
    var importInst *cueBuild.Instance
    buildInst.Imports = append(buildInst.Imports, importInst)
  }
  return
}

In summary:

• I call Complete() which populates ImportPaths
• For each item in ImportPaths, I fetch and assemble a new build instance, then add it to Imports

Is it safe to do this? Is there a better way?

[cueckoo]

Original reply by @mpvl in cuelang/cue#445 (comment)

That should be fine. The better way would be to fix cue.Build so that it doesn't need an in-sync Imports anymore. All of the information is contained in Files.

[cueckoo]

Original reply by @shykes in cuelang/cue#445 (comment)

Thanks!