// Best practices for developing Terraform resources and data sources in this provider. Use when creating new resources, modifying schema definitions, implementing CRUD operations, handling state transitions, or working with autogenerated resources.
Summarize a GitHub Actions test suite run for the mongodb/terraform-provider-mongodbatlas repo — fetches job logs, classifies failures, and produces a Slack summary led by an explicit code-regression verdict. Use when the user shares a workflow run URL or run_id, or when triggered by the test-suite webhook to decide whether on-call should investigate.
Standards for pull requests, documentation, and code review in this Terraform provider. Use when creating PRs, writing or editing documentation (schema descriptions, docs markdown, examples), reviewing code, or adding changelog entries. Covers PR structure, docs style guide, example conventions, and changelog practices.
Best practices for writing and organizing acceptance tests in this Terraform provider. Use when creating new acceptance tests, modifying existing tests, fixing flaky tests, or reviewing test code. Covers test consolidation, avoiding duplicates, plural data source ordering, and plan-only validation tests.
| name | terraform-resource-development |
| description | Best practices for developing Terraform resources and data sources in this provider. Use when creating new resources, modifying schema definitions, implementing CRUD operations, handling state transitions, or working with autogenerated resources. |
CreateOnly Plan Modifier for Non-Updatable AttributesUse customplanmodifier.CreateOnly() on attributes that can only be set at creation time and cannot be updated. This generates a clear error during plan if a user tries to change the value, instead of silently failing or producing confusing API errors.
UseStateForUnknown Plan ModifierBe cautious with UseStateForUnknown on Optional+Computed attributes. It can cause "inconsistent result after apply" errors when the API returns a value that differs from the prior state.
UseStateForUnknown unless you are certain the value never changes server-side when not defined by the user. If omitted, users see (known after apply) during plan, which is safe.Prefer Optional-only over Optional+Computed. With Optional+Computed, when a user removes an attribute from their config Terraform will not generate a plan diff because it treats the server-side value as authoritative. This means removals go undetected and the previous value silently persists. Only use Optional+Computed when the API genuinely returns a server-computed default for a field the user did not set.
Any change to a resource or data source must be backward-compatible by default. Treat the following as breaking unless the intent is explicitly documented and acknowledged:
Default or plan modifier that changes what gets written to state when the user omits a field.When a breaking change is genuinely required (e.g. aligning with an API deprecation), call it out explicitly in the PR description.