Fixes #322: Add support for lists in ignore_changes_to

[Guent4]

Summary

Enhanced the getDelta function to support ignoreList functionality when comparing slices containing map elements. Previously, slice comparisons only supported ignoring the entire slice or performed simple deep equality checks. Now, specific fields within slice elements can be ignored using dot notation.

Key Changes

Core Implementation

• Updated slice handling in getDelta: Modified slice comparison logic to support ignoreList for map elements within slices
• Added compareSlicesWithIgnoreListReflection: New function using Go's reflection package to handle different slice types ([]map[string]interface{}, []interface{}, etc.) while preserving type information
• Fixed _descendIgnoreList bug: Corrected array pre-allocation + append issue that was creating empty entries in ignore lists

Behavior & Rules

• Dot notation support: Use list.field syntax to ignore field in all elements of list
• Length changes always detected: Different slice lengths are always considered changes, ignoreList only applies to corresponding elements at same indices
• Type preservation: Maintains original slice types in the modified result
• Map-only ignoring: ignoreList only applies to slice elements that are maps; primitive elements use standard equality comparison

Enhanced Testing

• Added comprehensive test cases: New test scenarios for slice ignoreList functionality including:
  • Ignored fields in slice elements (list.val ignores val field in all list elements)
  • Partial ignoring (some fields ignored, others updated)
  • Mixed slice types with maps and primitives
  • Different slice lengths (always detected as changes)
  • Type preservation validation
• Enhanced TestHasDeltaModifiedResource: Added slice with ignoreList to existing test to validate complete functionality

Examples

Before (not supported)

o1 := {"users": [{"name": "alice", "secret": "old"}, {"name": "bob", "secret": "old"}]}
o2 := {"users": [{"name": "alice", "secret": "new"}, {"name": "bob", "secret": "new"}]}
ignoreList := []string{"users.secret"}
// Would detect changes even though only ignored fields changed

After (now supported)

o1 := {"users": [{"name": "alice", "secret": "old"}, {"name": "bob", "secret": "old"}]}  
o2 := {"users": [{"name": "alice", "secret": "new"}, {"name": "bob", "secret": "new"}]}
ignoreList := []string{"users.secret"}
// Returns: hasChanges = false, modified preserves original secret values

[Guent4]

Published the build of the fork to https://registry.terraform.io/providers/Guent4/restapi/2.1.0 and verified that it works with my use case.

Data is in the format of:

{
  "prefixes": [
    {
      "prefix": "<CIDR>",
      "family": <FAMILY>,
      "status": "<STATUS>",
      "role": "<ROLE>",
      "description": "<DESCRIPTION>",
      "tags": [],
      "prefix_role": {
        ...
      },
      "custom_fields": {
        ...
      },
      "id": 61999,
      "created_at": "<TIME>",
      "updated_at": "<TIME>"
    }
  ],
  "total_results": 1
}

When I set

  ignore_changes_to = [
    "changed_by",
    "prefixes.created_at",
    "prefixes.custom_fields",
    "prefixes.family",
    "prefixes.id",
    "prefixes.prefix_role",
    "prefixes.updated_at",
    "total_results",
  ]

, changes corresponding to the fields, most of which are auto-generated/auto-updated, are properly ignored by the Terraform resource.

[DRuggeri]

Thanks so much for this PR, @Guent4! Wanted to drop a note that this is on the radar and I'll be taking a look soon. It will happen after updating the provider to the latest TFSDK, so expect a whole pile of conflicts/etc coming. I'll see what can be picked into the new branch from there!

[DRuggeri]

While in the neighborhood, do you mind comparing your objective/impl to #338? I haven't dug in to either just yet, but if they're compatible/incompatible that'd be good to know off the bat 😄