Error: Reference to undeclared resource

TL;DR: Something in your config references a resource that doesn't exist: a typo, a deleted block, or a renamed label whose references weren't updated. The error names the file, line, and address. Fix the reference, or add the missing resource back.

Error: Reference to undeclared resource

  on retire.tf line 5, in output "build_info_path":
   5:   value = local_file.build_info.filename

There is no managed resource "local_file" "build_info" definition in the root
module.

Steps

1. Read the address in the error (local_file.build_info above) and the location of the reference (file, line).

Expected: you know exactly which reference is dangling.

1. Search for the resource block: grep -rn 'resource "local_file" "build_info"' .

Expected: either no block (it was deleted or never existed) or a block with a different label (it was renamed).

1. Fix it one of these ways:

• Typo: correct the reference to the real label.
• Deleted by accident: restore the block.
• Renamed on purpose: update every reference (outputs, locals, other resources), or add a moved block so tofu tracks the rename.
• Retiring on purpose: delete the consumers too, or use a removed block to forget it without destroying.

Expected: no dangling references remain.

1. Run tofu validate.

Expected: Success! The configuration is valid.

When this applies

• tofu plan or tofu validate fails naming a type.name address with no ... definition in the root module (or in a child module).
• Right after renaming or deleting a resource block.

When it doesn't apply

• Error: Reference to undeclared input variable is the variable version; same idea, different fix location.
• Error: Reference to undeclared data source means a data block is missing.
• A reference that exists but has count = 0 fails differently (Invalid index); that's not this error.

Tool versions

All OpenTofu versions.

Why it happens

References are resolved statically before anything is planned. A reference to an address with no block is a config bug by definition, so tofu fails fast and names every dangling reference instead of guessing.

Edge cases

• Renames dangle in bulk: renaming a resource label breaks every reference at once. A moved { from, to } block renames the state address too, so you don't get this error at all.
• tofu state mv renames state without touching config; if you do one without the other, expect this error or a destroy-and-recreate plan.
• Module-internal references say in module "name" instead of in the root module; fix them inside the module source.