tree fbc7b49a6c1fcd4dd9be6fcbd751e9e6d3e579fe
parent 5691606b4e246f73948993d3a7d0be7d0e6286f3
author Marcel van Lohuizen <mpvl@golang.org> 1610646404 +0100
committer Marcel van Lohuizen <mpvl@golang.org> 1610710729 +0000

internal/core/adt: fix cycle bug

In the new implementation, ctx.Unify(ctx, arc, AllArcs) had to go.
The issue is that the desired evaluation state was not passed
down and AllArcs was used unconditionally. This means that for
Evaluate it would evaluate too much, causing a cycle to be
triggered.

With the new incremental algorithm, this call to Unify was also
redundant. In fact, not calling it results in more consistent error
messages and a more consistent ordering of evaluation.

It has therefore been removed.

Fixes #622

This also improves various other evaluations.

The changes in errormessages to structural.txtar are typciall for
changes in order of evaluation are fine and in spec, as long as the
same set of nodes are marked as an error (sub nodes of erroring
nodes may be removed or added from the output).

Change-Id: Icbd24891a48e421be900df40f622fd344a0bed4c
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/8211
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: CUE cueckoo <cueckoo@gmail.com>
Reviewed-by: Paul Jolly <paul@myitcv.org.uk>