Description

Upstream Issue: https://github.com/tektoncd/pipeline/issues/8862

When using the local resolver, parameter substitution doesn't work correctly for default values that reference other parameters. The literal string (e.g., $(params.fallback-param)) is used instead of the substituted value.

Expected Behavior

Using default value inherited from another param should work with local resolver, just like it does with remote resolvers:

apiVersion: tekton.dev/v1
kind: Pipeline
metadata:   name: pipeline-with-default-value-from-param
spec:   params:     - name: fallback-param
      type: string
      default: "fallback value"
    - name: param
      type: string
      default: $(params.fallback-param)  # Should resolve to "fallback value"

Actual Behavior

With local resolver, the value is the literal string $(params.fallback-param) instead of the resolved value.

This works correctly with remote resolvers but not with local resolver.

Impact

• Inconsistent behavior between local and remote resolvers
• Limits ability to use fallback patterns in Pipelines/Tasks
• Breaks existing patterns when switching from remote to local resolution

Use Case

Need to use default values inherited from another param as a fallback (overridable by PipelineRun). This pattern is common for providing sensible defaults while allowing override.

Environment

• Affects: Local Resolver
• Works correctly with: Remote Resolvers