Which errors does 'terraform validate' report related to configuration consistency?

The command 'terraform validate' primarily checks for syntax and configuration errors within the Terraform configuration files. Among the given choices, declaring a resource identifier more than once is a clear violation of Terraform's resource declaration rules. When Terraform encounters duplicate resource identifiers, it cannot determine which resource to reference, leading to ambiguity and potential functional issues in the infrastructure definition.

This form of error directly affects the integrity and reliability of the configuration, as Terraform expects resource names to be unique within the same module. Thus, 'terraform validate' will report this situation as an error, allowing the user to correct it before proceeding to apply changes.

In contrast, duplicating variable names and inconsistent indentation may not necessarily be flagged as critical errors by 'terraform validate,' as it primarily focuses on semantic correctness rather than stylistic consistency. Encoding issues in configuration files could potentially lead to parsing errors but would likely arise during the execution phase rather than during validation.