emit apply change summary on failure

[purajit]

Resolves #38343

Target Release

1.16.x

CHANGELOG entry

• This change is user-facing and I added a changelog entry.
• This change is not user-facing.

Testing/results

Besides unit tests, ran on my local terraform playground:

With this file

resource "null_resource" "will_succeed" {
}

resource "local_file" "will_fail" {
  filename = "/definitely/does/not/exist/out.txt"
  content  = ""
}

we used to get:

> terraform apply -auto-approve

Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  # local_file.will_fail will be created
  + resource "local_file" "will_fail" {
      + content_base64sha256 = (known after apply)
      + content_base64sha512 = (known after apply)
      + content_md5          = (known after apply)
      + content_sha1         = (known after apply)
      + content_sha256       = (known after apply)
      + content_sha512       = (known after apply)
      + directory_permission = "0777"
      + file_permission      = "0777"
      + filename             = "/definitely/does/not/exist/out.txt"
      + id                   = (known after apply)
        # (1 unchanged attribute hidden)
    }

  # null_resource.will_succeed will be created
  + resource "null_resource" "will_succeed" {
      + id = (known after apply)
    }

Plan: 2 to add, 0 to change, 0 to destroy.
null_resource.will_succeed: Creating...
local_file.will_fail: Creating...
null_resource.will_succeed: Creation complete after 0s [id=2020311957725937646]
╷
│ Error: Create local file error
│
│   with local_file.will_fail,
│   on main.tf line 4, in resource "local_file" "will_fail":
│    4: resource "local_file" "will_fail" {
│
│ An unexpected error occurred while creating file directory
│
│ +Original Error: mkdir /definitely: read-only file system
╵

> terraform apply -auto-approve -json
{"@level":"info","@message":"Terraform 1.14.7","@module":"terraform.ui","@timestamp":"2026-04-03T16:18:38.435670-07:00","terraform":"1.14.7","type":"version","ui":"1.2"}
{"@level":"info","@message":"null_resource.will_succeed: Plan to create","@module":"terraform.ui","@timestamp":"2026-04-03T16:18:38.559405-07:00","change":{"resource":{"addr":"null_resource.will_succeed","module":"","resource":"null_resource.will_succeed","implied_provider":"null","resource_type":"null_resource","resource_name":"will_succeed","resource_key":null},"action":"create"},"type":"planned_change"}
{"@level":"info","@message":"local_file.will_fail: Plan to create","@module":"terraform.ui","@timestamp":"2026-04-03T16:18:38.559444-07:00","change":{"resource":{"addr":"local_file.will_fail","module":"","resource":"local_file.will_fail","implied_provider":"local","resource_type":"local_file","resource_name":"will_fail","resource_key":null},"action":"create"},"type":"planned_change"}
{"@level":"info","@message":"Plan: 2 to add, 0 to change, 0 to destroy.","@module":"terraform.ui","@timestamp":"2026-04-03T16:18:38.559448-07:00","changes":{"add":2,"change":0,"import":0,"remove":0,"action_invocation":0,"operation":"plan"},"type":"change_summary"}
{"@level":"info","@message":"null_resource.will_succeed: Creating...","@module":"terraform.ui","@timestamp":"2026-04-03T16:18:38.592476-07:00","hook":{"resource":{"addr":"null_resource.will_succeed","module":"","resource":"null_resource.will_succeed","implied_provider":"null","resource_type":"null_resource","resource_name":"will_succeed","resource_key":null},"action":"create"},"type":"apply_start"}
{"@level":"info","@message":"null_resource.will_succeed: Creation complete after 0s [id=2809849765760413623]","@module":"terraform.ui","@timestamp":"2026-04-03T16:18:38.593045-07:00","hook":{"resource":{"addr":"null_resource.will_succeed","module":"","resource":"null_resource.will_succeed","implied_provider":"null","resource_type":"null_resource","resource_name":"will_succeed","resource_key":null},"action":"create","id_key":"id","id_value":"2809849765760413623","elapsed_seconds":0},"type":"apply_complete"}
{"@level":"info","@message":"local_file.will_fail: Creating...","@module":"terraform.ui","@timestamp":"2026-04-03T16:18:38.593285-07:00","hook":{"resource":{"addr":"local_file.will_fail","module":"","resource":"local_file.will_fail","implied_provider":"local","resource_type":"local_file","resource_name":"will_fail","resource_key":null},"action":"create"},"type":"apply_start"}
{"@level":"info","@message":"local_file.will_fail: Creation errored after 0s","@module":"terraform.ui","@timestamp":"2026-04-03T16:18:38.602363-07:00","hook":{"resource":{"addr":"local_file.will_fail","module":"","resource":"local_file.will_fail","implied_provider":"local","resource_type":"local_file","resource_name":"will_fail","resource_key":null},"action":"create","elapsed_seconds":0},"type":"apply_errored"}
{"@level":"error","@message":"Error: Create local file error","@module":"terraform.ui","@timestamp":"2026-04-03T16:18:38.610577-07:00","diagnostic":{"severity":"error","summary":"Create local file error","detail":"An unexpected error occurred while creating file directory\n\n+Original Error: mkdir /definitely: read-only file system","address":"local_file.will_fail","range":{"filename":"main.tf","start":{"line":4,"column":35,"byte":79},"end":{"line":4,"column":36,"byte":80}},"snippet":{"context":"resource \"local_file\" \"will_fail\"","code":"resource \"local_file\" \"will_fail\" {","start_line":4,"highlight_start_offset":34,"highlight_end_offset":35,"values":[]}},"type":"diagnostic"}

Now we get:

> ../../hashicorp/terraform/bin/terraform apply -auto-approve
Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  # local_file.will_fail will be created
  + resource "local_file" "will_fail" {
      + content_base64sha256 = (known after apply)
      + content_base64sha512 = (known after apply)
      + content_md5          = (known after apply)
      + content_sha1         = (known after apply)
      + content_sha256       = (known after apply)
      + content_sha512       = (known after apply)
      + directory_permission = "0777"
      + file_permission      = "0777"
      + filename             = "/definitely/does/not/exist/out.txt"
      + id                   = (known after apply)
        # (1 unchanged attribute hidden)
    }

  # null_resource.will_succeed will be created
  + resource "null_resource" "will_succeed" {
      + id = (known after apply)
    }

Plan: 2 to add, 0 to change, 0 to destroy.
null_resource.will_succeed: Creating...
null_resource.will_succeed: Creation complete after 0s [id=3755547938556189260]
local_file.will_fail: Creating...
╷
│ Error: Create local file error
│
│   with local_file.will_fail,
│   on main.tf line 4, in resource "local_file" "will_fail":
│    4: resource "local_file" "will_fail" {
│
│ An unexpected error occurred while creating file directory
│
│ +Original Error: mkdir /definitely: read-only file system
╵

Apply incomplete with errors! Resources: 1 added, 0 changed, 0 destroyed.

> echo $?
1

> ../../hashicorp/terraform/bin/terraform apply -auto-approve -json
{"@level":"info","@message":"Terraform 1.16.0-dev","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.220957-07:00","terraform":"1.16.0-dev","type":"version","ui":"1.3"}
{"@level":"info","@message":"null_resource.will_succeed: Plan to create","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.892383-07:00","change":{"resource":{"addr":"null_resource.will_succeed","module":"","resource":"null_resource.will_succeed","implied_provider":"null","resource_type":"null_resource","resource_name":"will_succeed","resource_key":null},"action":"create"},"type":"planned_change"}
{"@level":"info","@message":"local_file.will_fail: Plan to create","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.892441-07:00","change":{"resource":{"addr":"local_file.will_fail","module":"","resource":"local_file.will_fail","implied_provider":"local","resource_type":"local_file","resource_name":"will_fail","resource_key":null},"action":"create"},"type":"planned_change"}
{"@level":"info","@message":"Plan: 2 to add, 0 to change, 0 to destroy.","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.892447-07:00","changes":{"add":2,"change":0,"import":0,"remove":0,"action_invocation":0,"operation":"plan"},"type":"change_summary"}
{"@level":"info","@message":"null_resource.will_succeed: Creating...","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.929490-07:00","hook":{"resource":{"addr":"null_resource.will_succeed","module":"","resource":"null_resource.will_succeed","implied_provider":"null","resource_type":"null_resource","resource_name":"will_succeed","resource_key":null},"action":"create"},"type":"apply_start"}
{"@level":"info","@message":"local_file.will_fail: Creating...","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.929979-07:00","hook":{"resource":{"addr":"local_file.will_fail","module":"","resource":"local_file.will_fail","implied_provider":"local","resource_type":"local_file","resource_name":"will_fail","resource_key":null},"action":"create"},"type":"apply_start"}
{"@level":"info","@message":"null_resource.will_succeed: Creation complete after 0s [id=8397979251889827490]","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.930005-07:00","hook":{"resource":{"addr":"null_resource.will_succeed","module":"","resource":"null_resource.will_succeed","implied_provider":"null","resource_type":"null_resource","resource_name":"will_succeed","resource_key":null},"action":"create","id_key":"id","id_value":"8397979251889827490","elapsed_seconds":0},"type":"apply_complete"}
{"@level":"info","@message":"local_file.will_fail: Creation errored after 0s","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.937911-07:00","hook":{"resource":{"addr":"local_file.will_fail","module":"","resource":"local_file.will_fail","implied_provider":"local","resource_type":"local_file","resource_name":"will_fail","resource_key":null},"action":"create","elapsed_seconds":0},"type":"apply_errored"}
{"@level":"error","@message":"Error: Create local file error","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.945866-07:00","diagnostic":{"severity":"error","summary":"Create local file error","detail":"An unexpected error occurred while creating file directory\n\n+Original Error: mkdir /definitely: read-only file system","address":"local_file.will_fail","range":{"filename":"main.tf","start":{"line":4,"column":35,"byte":79},"end":{"line":4,"column":36,"byte":80}},"snippet":{"context":"resource \"local_file\" \"will_fail\"","code":"resource \"local_file\" \"will_fail\" {","start_line":4,"highlight_start_offset":34,"highlight_end_offset":35,"values":[]}},"type":"diagnostic"}
{"@level":"info","@message":"Apply incomplete with errors! Resources: 1 added, 0 changed, 0 destroyed.","@module":"terraform.ui","@timestamp":"2026-04-03T16:55:34.946403-07:00","changes":{"add":1,"change":0,"import":0,"remove":0,"action_invocation":0,"operation":"apply","errored":true},"type":"change_summary"}

> echo $?
1

[hashicorp-cla-app]

All committers have signed the CLA.