### Terraform Version ```shell Terraform v1.13.4 on linux_amd64 ``` ### Terraform Configuration Files ```terraform variable "t" { type = string } resource "terraform_data" "t" { count = 100 input = var.t } resource "terraform_data" "r" { count = 100 input = count.index lifecycle { replace_triggered_by = [terraform_data.t[count.index]] } } ``` ### Debug Output https://gist.githubusercontent.com/g7r/759be7835d33f6fbc38828f61fdff4f8/raw/03ab3123308cd4ef6f50ef65863923b374e2cc94/tftrace.log ### Expected Behavior ``` Plan: 100 to add, 100 to change, 100 to destroy. ``` ### Actual Behavior ``` Plan: 16 to add, 97 to change, 16 to destroy. ``` The numbers vary every time. ### Steps to Reproduce 1. `terraform init` 2. `terraform apply -var t=a` 3. `terraform plan -var t=b -replace 'terraform_data.r[0]' -replace 'terraform_data.r[1]' -replace 'terraform_data.r[2]'` ### Additional Context `b.ForceReplace` slice obtained from command line arguments is being passed by reference to graph nodes: https://github.com/hashicorp/terraform/blob/v1.13.4/internal/terraform/graph_builder_plan.go#L308 The number of `-replace` arguments matters. If `len(b.ForceReplace) == cap(b.ForceReplace)`, the bug doesn't reproduce. It doesn't matter which addresses to use for `-replace`. E.g. you can replace 3rd action with: * `terraform plan -var t=b -replace a.a -replace a.b -replace a.c` * `terraform plan -var t=b -replace a.a -replace a.a -replace a.a` The same slice is being concurrently modified: https://github.com/hashicorp/terraform/blob/v1.13.4/internal/terraform/node_resource_plan_instance.go#L572 I suggest making a copy of the slice at `graph_builder_plan.go`. ### References _No response_ ### Generative AI / LLM assisted development? _No response_