Non-HashiCorp providers passed under aliases are reporting errors when running terraform plan with not-initialized module

[magul]

Terraform Version

$ terraform version
Terraform v1.14.3
on darwin_arm64
+ provider registry.terraform.io/cyrilgdn/postgresql v1.26.0

Terraform Configuration Files

./main.tf

terraform {
  required_providers {
    postgresql = {
      source = "cyrilgdn/postgresql"
    }
  }
}

provider "postgresql" {
  alias    = "source"
  host     = "127.0.0.1"
  port     = 5432
  username = "postgres"
  password = "postgres"
}

provider "postgresql" {
  alias    = "destination"
  host     = "127.0.0.1"
  port     = 5432
  username = "postgres"
  password = "postgres"
}

module "replication" {
  source = "./replication"
  providers = {
    postgresql.source = postgresql.source
    postgresql.destination = postgresql.destination
  }
}

# module "new" {
#   source = "./new"
# }

./replication/main.tf

terraform {
  required_providers {
    postgresql = {
      source = "cyrilgdn/postgresql"
      configuration_aliases = [
        postgresql.source,
        postgresql.destination,
      ]
    }
  }
}

./new

(Empty directory)

Debug Output

$ TF_LOG=DEBUG terraform plan
2026-01-15T15:45:29.226+0100 [INFO]  Terraform version: 1.14.3
2026-01-15T15:45:29.227+0100 [DEBUG] using github.com/hashicorp/go-tfe v1.94.0
2026-01-15T15:45:29.227+0100 [DEBUG] using github.com/hashicorp/hcl/v2 v2.24.0
2026-01-15T15:45:29.227+0100 [DEBUG] using github.com/hashicorp/terraform-svchost v0.1.1
2026-01-15T15:45:29.227+0100 [DEBUG] using github.com/zclconf/go-cty v1.16.3
2026-01-15T15:45:29.227+0100 [INFO]  Go runtime version: go1.25.5
2026-01-15T15:45:29.227+0100 [INFO]  CLI args: []string{"/usr/local/Cellar/tfenv/3.0.0/versions/1.14.3/terraform", "plan"}
2026-01-15T15:45:29.227+0100 [DEBUG] Attempting to open CLI config file: /Users/magul/.terraformrc
2026-01-15T15:45:29.227+0100 [DEBUG] File doesn't exist, but doesn't need to. Ignoring.
2026-01-15T15:45:29.227+0100 [DEBUG] ignoring non-existing provider search directory terraform.d/plugins
2026-01-15T15:45:29.227+0100 [DEBUG] ignoring non-existing provider search directory /Users/magul/.terraform.d/plugins
2026-01-15T15:45:29.227+0100 [DEBUG] ignoring non-existing provider search directory /Users/magul/Library/Application Support/io.terraform/plugins
2026-01-15T15:45:29.227+0100 [DEBUG] ignoring non-existing provider search directory /Library/Application Support/io.terraform/plugins
2026-01-15T15:45:29.227+0100 [INFO]  CLI command args: []string{"plan"}
2026-01-15T15:45:29.241+0100 [DEBUG] checking for provisioner in "."
2026-01-15T15:45:29.241+0100 [DEBUG] checking for provisioner in "/usr/local/Cellar/tfenv/3.0.0/versions/1.14.3"
2026-01-15T15:45:29.242+0100 [INFO]  backend/local: starting Plan operation
╷
│ Error: Provider type mismatch
│
│   on main.tf line 4, in module "replication":
│    4:     postgresql.source = postgresql.source
│
│ The local name "postgresql.source" in the root module represents provider "hashicorp/postgresql", but "postgresql.source" in
│ module.replication represents "cyrilgdn/postgresql".
│
│ Each provider has its own distinct configuration schema and provider types, so this module's "postgresql.source" can be assigned
│ only a configuration for cyrilgdn/postgresql, which is not required by module.replication.
╵
╷
│ Error: Provider type mismatch
│
│   on main.tf line 5, in module "replication":
│    5:     postgresql.destination = postgresql.destination
│
│ The local name "postgresql.destination" in the root module represents provider "hashicorp/postgresql", but "postgresql.destination"
│ in module.replication represents "cyrilgdn/postgresql".
│
│ Each provider has its own distinct configuration schema and provider types, so this module's "postgresql.destination" can be
│ assigned only a configuration for cyrilgdn/postgresql, which is not required by module.replication.
╵
╷
│ Error: Module not installed
│
│   on main.tf line 9:
│    9: module "new" {
│
│ This module is not yet installed. Run "terraform init" to install all modules required by this configuration.
╵

Expected Behavior

Terraform should properly recognize non-HashiCorp providers, even if they are passed as aliases to sub-modules.

Actual Behavior

When running plan (with not-yet-initialized module) Terraform complains about

│ The local name "postgresql.destination" in the root module represents provider "hashicorp/postgresql", but "postgresql.destination"
│ in module.replication represents "cyrilgdn/postgresql".
│
│ Each provider has its own distinct configuration schema and provider types, so this module's "postgresql.destination" can be
│ assigned only a configuration for cyrilgdn/postgresql, which is not required by module.replication.

Steps to Reproduce

1. run terraform init
2. run terraform plan
3. uncomment

module "new" {
  source = "./new"
}

4. run terraform plan
5. observe errors

Additional Context

AFAIK this is limited only to providers passed to aliases (default providers are not complained about).

After running terraform init (which succeed) terraform plan do not complain anymore.

References

#33784 - this looks similar, but is about terraform init, where in my situation terraform init make problem go away.

Generative AI / LLM assisted development?

No response

[crw]

Thanks for this report!