Invalid defaults for merge_commit_message, merge_commit_title

[guineveresaenger]

I run terraform import on a github repository with ☑️ Allow Merge Commits and set to "Default to pull request title and description".

Pulling out the resulting state into my main.tf:

terraform {
  required_providers {
    github = {
      source  = "integrations/github"
      version = "~> 5.0"
    }
  }
}

# Configure the GitHub Provider
provider "github" {
    token = xxx
    owner = pulumi
}

resource "github_repository" "myrepo" {
    name = "myrepo"
    description = "A test repo"
    has_downloads = true
    has_issues= true
    has_projects= true
    has_wiki= true
    merge_commit_message= "PR_BODY"
    merge_commit_title= "PR_TITLE"
    delete_branch_on_merge = true
}

No changes when running terraform apply.

Now, I would like to disable merge commits, so I set allow_merge_commit to false and remove merge_commit_message and merge_commit_title:

resource "github_repository" "myrepo" {
    name = "myrepo"
    description = "A test repo"
    has_downloads = true
    has_issues= true
    has_projects= true
    has_wiki= true
#     merge_commit_message= "PR_BODY"
#     merge_commit_title= "PR_TITLE"
    delete_branch_on_merge = true
    allow_merge_commit =  false
}

And I get the following output, which tells me that somehow the defaults for the message and title fields are wrong.

Plan:

Terraform will perform the following actions:

  # github_repository.myrepo will be updated in-place
  ~ resource "github_repository" "myrepo" {
      ~ allow_merge_commit          = true -> false
        id                          = "myrepo"
      ~ merge_commit_message        = "PR_BODY" -> "PR_TITLE"
      ~ merge_commit_title          = "PR_TITLE" -> "MERGE_MESSAGE"
        name                        = "myrepo"
        # (30 unchanged attributes hidden)
    }

Plan: 0 to add, 1 to change, 0 to destroy.

Apply:

Do you want to perform these actions?
  Terraform will perform the actions described above.
  Only 'yes' will be accepted to approve.

  Enter a value: yes

github_repository.myrepo: Modifying... [id=myrepo]
╷
│ Error: PATCH https://api.github.com/repos/pulumi/myrepo: 422 Validation Failed [{Resource:Repository Field:merge_commit_allowed Code:invalid Message:Sorry, you need to allow the merge commit strategy in order to set the default merge commit message title and message. (no_merge_strategy)}]
│ 
│   with github_repository.myrepo,
│   on main.tf line 16, in resource "github_repository" "myrepo":
│   16: resource "github_repository" "myrepo" {
│ 
╵

I thought it was a little odd that the value for merge_commit_message wanted to update "PR_BODY" -> "PR_TITLE"
and likewise merge_commit_title to "PR_BODY" -> "MERG_MESSAGE". It looks like someone confused those two defaults? I went looking and found the go-client is confused as well:
https://github.com/google/go-github/blob/master/github/repos.go#L75

Regardless, this provider should not attempt to re-set these two fields at the same time as disabling merge commits altogether.

[tuwid]

experiencing same issue with the merge strategies, regardless of the tittle

[juicybaba]

same issue.
quick workaround.

1. enable allow_merge_commit in the code and apply.
2. disable allow_merge_commit in the code and apply.

[meliamzz]

I have the same issue, and it's seems more related to the github API. I raised a ticket, they are investigating.
I found out a workaround :

• Go on the Pull request settings of the repo (in the UI)
• Enable merge commit
• And set the default commit message to -> Default message
• Disable merge commit

It should be fixed.

[github-actions]

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