New Check: Avoid Invalid ConflictsWith Values

[bflad]

Description

Terraform Plugin SDK v1 performs separate validation of the attribute keys given to helper/schema.Schema.ConflictsWith versus the method used to perform the conflict logic during runtime. Differences in the logic leave ambiguity between the flatmap syntax accepted by the schema validation versus what attributes can actually exist during runtime and report the user interface error messaging. While any logic fixes will need to occur in the SDK, the linter can at least report always invalid index syntax for these strings, since ConflictsWith cannot properly work with map syntax (neither for TypeMap attributes (properly fails schema validation) nor TypeList/TypeSet configuration block attributes (never will show conflict)).

Flagged Code

&schema.Schema{
  ConflictsWith: []string{"config_block_attr.nested_attr"},
},

&schema.Schema{
  ConflictsWith: []string{"config_block_attr.0.nested_attr.really_nested_attr"},
},

Passing Code

&schema.Schema{
  ConflictsWith: []string{"config_block_attr.0.nested_attr"},
},

&schema.Schema{
  ConflictsWith: []string{"config_block_attr.0.nested_attr.0.really_nested_attr"},
},

References

• Using ConflictsWith with Lists or Sets hashicorp/terraform-plugin-sdk#71

Amongst many:

• Add Media Connect Flow resource hashicorp/terraform-provider-aws#7431 (comment)