Ignore .tflint.hcl (#1075)

* Ignore .tflint.hcl

runatlantis.io/docs/repo-level-atlantis-yaml.md

@@ -229,7 +229,7 @@ Atlantis supports this but requires the `name` key to be specified. See [Custom
 ### Autoplan
 ```yaml
 enabled: true
-when_modified: ["*.tf"]
+when_modified: ["*.tf", "terragrunt.hcl"]
 ```
 | Key           | Type          | Default        | Required | Description                                                                                                                                                                                                                                                       |
 |---------------|---------------|----------------|----------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

server/events/project_finder.go

@@ -40,6 +40,9 @@ type ProjectFinder interface {
 	DetermineProjectsViaConfig(log *logging.SimpleLogger, modifiedFiles []string, config valid.RepoCfg, absRepoDir string) ([]valid.Project, error)
 }
 
+// ignoredFilenameFragments contains filename fragments to ignore while looking at changes
+var ignoredFilenameFragments = []string{"terraform.tfstate", "terraform.tfstate.backup", "tflint.hcl"}
+
 // DefaultProjectFinder implements ProjectFinder.
 type DefaultProjectFinder struct{}
 
@@ -134,18 +137,16 @@ func (p *DefaultProjectFinder) DetermineProjectsViaConfig(log *logging.SimpleLog
 func (p *DefaultProjectFinder) filterToTerraform(files []string) []string {
 	var filtered []string
 	for _, fileName := range files {
-		// Filter out tfstate files since they usually checked in by accident
-		// and regardless, they don't affect a plan.
-		if !p.isStatefile(fileName) && (strings.Contains(fileName, ".tf") || filepath.Base(fileName) == "terragrunt.hcl") {
+		if !p.shouldIgnore(fileName) && (strings.Contains(fileName, ".tf") || filepath.Base(fileName) == "terragrunt.hcl") {
 			filtered = append(filtered, fileName)
 		}
 	}
 	return filtered
 }
 
-// isStatefile returns true if fileName is a terraform statefile or backup.
-func (p *DefaultProjectFinder) isStatefile(fileName string) bool {
-	for _, s := range []string{"terraform.tfstate", "terraform.tfstate.backup"} {
+// shouldIgnore returns true if we shouldn't trigger a plan on changes to this file.
+func (p *DefaultProjectFinder) shouldIgnore(fileName string) bool {
+	for _, s := range ignoredFilenameFragments {
 		if strings.Contains(fileName, s) {
 			return true
 		}

server/events/project_finder_test.go

@@ -53,6 +53,7 @@ func setupTmpRepos(t *testing.T) {
 	Ok(t, err)
 	files := []string{
 		"non-tf",
+		".tflint.hcl",
 		"terraform.tfstate.backup",
 		"project1/main.tf",
 		"project1/terraform.tfstate",
@@ -123,6 +124,12 @@ func TestDetermineProjects(t *testing.T) {
 			nil,
 			nestedModules1,
 		},
+		{
+			"Should ignore .tflint.hcl files and return an empty list",
+			[]string{".tflint.hcl", "project1/.tflint.hcl"},
+			nil,
+			nestedModules1,
+		},
 		{
 			"Should plan in the parent directory from modules if that dir has a main.tf",
 			[]string{"project1/modules/main.tf"},