Multiple plans with a targeted apply with auto merge will incorrectly merge pr

[nitrocode]

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---

Overview of the Issue

Reproduction Steps

If the following is run

atlantis plan

And it affects multiple resources.

aws_s3_bucket.one
aws_s3_bucket.two

If this is run, the targeted apply will merge the pr leaving the other resource to be applied on a subsequent pr

atlantis apply -- -target='aws_s3_bucket.one'

Logs

Environment details

• Atlantis version: 0.21.0
• --automerge

https://www.runatlantis.io/docs/server-configuration.html#automerge

Additional Context

atlantis/server/events/vcs/github_client.go

Line 499 in db9f022

mergeResult, _, err := g.client.PullRequests.Merge(

atlantis/server/events/automerger.go

Line 35 in db9f022

err := c.VCSClient.MergePull(ctx.Pull, pullOptions)

atlantis/server/events/automerger.go

Lines 47 to 53 in db9f022

	// automergeEnabled returns true if automerging is enabled in this context.
	func (c *AutoMerger) automergeEnabled(projectCmds []command.ProjectContext) bool {
	// If the global automerge is set, we always automerge.
	return c.GlobalAutomerge ||
	// Otherwise we check if this repo is configured for automerging.
	(len(projectCmds) > 0 && projectCmds[0].AutomergeEnabled)
	}

atlantis/server/core/runtime/apply_step_runner.go

Line 66 in db9f022

func (a *ApplyStepRunner) hasTargetFlag(ctx command.ProjectContext, extraArgs []string) bool {

atlantis/server/events/apply_command_runner.go

Line 165 in db9f022

if a.autoMerger.automergeEnabled(projectCmds) && !cmd.AutoMergeDisabled {

The hasTargetFlag function result could be passed down to the automergeEnabled. If the flag is true then we can set automerge to false.

Well this is interesting. Looks like targeted applies were previously prevented but perhaps this block is only caught with atlantis apply -target convention and not with the atlantis apply -- -target convention.

Related pr #403

atlantis/server/core/runtime/apply_step_runner.go

Line 26 in db9f022

if a.hasTargetFlag(ctx, extraArgs) {

---

workaround: use --auto-merge-disabled

Either use a naked plan and targeted apply

atlantis plan
atlantis apply --auto-merge-disabled -- -target='aws_s3_bucket.one'

or a targeted plan and a naked apply

atlantis plan -- -target='aws_s3_bucket.one'
atlantis apply --auto-merge-disabled

atlantis/server/events/comment_parser.go

Line 40 in db9f022

autoMergeDisabledFlagLong = "auto-merge-disabled"

atlantis/server/events/comment_parser.go

Lines 333 to 335 in db9f022

	if autoMergeDisabled {
	flags = fmt.Sprintf("%s --%s", flags, autoMergeDisabledFlagLong)
	}

[Loic-R]

Hello,
Workaround works well when having 1 project in the repository or if targeted plan/apply is run in last position, after all other projects has been applied with -p project.
Otherwise, if targeted plan is run first for example ; even with auto-merge-disabled flag, and another project is applied, then the PR is automerged

Is an approach where targeted plan generate failed status check considered? Or maybe an option to allow not considering a targeted plan/apply as a valid commit check?

[nitrocode]

We'd need to somehow check if -target is in the comment and if so, add an empty file like .terraform-targeted so when you atlantis apply, it checks if the file exists. If the file exists, do not auto merge. If it doesnt exist, automerge unless the automerge flag is passed.