Fix creation of release branches (#31)

* Do not enforce status checks and workflows on create

When enforcing status checks and workflows on creation, it becomes
impossible to create new release branches or push the initial commit to
main of a newly created repo.

Signed-off-by: Daniel Gonzalez Nothnagel <daniel.gonzalez.nothnagel@sap.com>

* Do not enforce linear history

When the default branch contains a merge commit in its history, it will
become impossible to create release branches with linear history.

Signed-off-by: Daniel Gonzalez Nothnagel <daniel.gonzalez.nothnagel@sap.com>

---------

Signed-off-by: Daniel Gonzalez Nothnagel <daniel.gonzalez.nothnagel@sap.com>

Author: gonzolino

automation/main.tf

@@ -55,6 +55,8 @@ module "repositories" {
       }
       rules = {
         required_status_checks = {
+          do_not_enforce_on_create = true
+
           required_check = flatten([
             for app_slug, contexts in each.value.required_status_checks : [
               for context in contexts : {

automation/modules/github_repository/main.tf

@@ -56,6 +56,7 @@ resource "github_repository_ruleset" "ruleset" {
       for_each = each.value.rules.required_status_checks != null ? [each.value.rules.required_status_checks] : []
       content {
         strict_required_status_checks_policy = required_status_checks.value.strict_required_status_checks_policy
+        do_not_enforce_on_create             = required_status_checks.value.do_not_enforce_on_create
 
         dynamic "required_check" {
           for_each = required_status_checks.value.required_check

automation/modules/github_repository/variables.tf

@@ -91,6 +91,7 @@ variable "rulesets" {
 
       required_status_checks = optional(object({
         strict_required_status_checks_policy = optional(bool)
+        do_not_enforce_on_create             = optional(bool)
         required_check = list(object({
           context        = string
           integration_id = optional(number)

automation/rulesets.tf

@@ -23,7 +23,9 @@ resource "github_organization_ruleset" "default_release" {
 
   rules {
     deletion                = true
-    non_fast_forward        = true
+    # We can not enforce linear history on repos that have merge commits in their history.
+    # Enforcing it will block creation of release branches.
+    non_fast_forward        = false
     required_linear_history = true
 
     pull_request {
@@ -36,14 +38,16 @@ resource "github_organization_ruleset" "default_release" {
     }
 
     required_status_checks {
+      do_not_enforce_on_create = true
+
       required_check {
         context        = "DCO"
         integration_id = data.github_app.apps["dco"].id
       }
     }
 
     required_workflows {
-      do_not_enforce_on_create = false
+      do_not_enforce_on_create = true
 
       required_workflow {
         repository_id = module.repositories["community"].repo_id