Add ranges to terraform_required_version errors

Author: rdimartino

rules/terraform_required_version.go

@@ -1,6 +1,8 @@
 package rules
 
 import (
+	"path/filepath"
+
 	"github.com/hashicorp/hcl/v2"
 	"github.com/terraform-linters/tflint-plugin-sdk/hclext"
 	"github.com/terraform-linters/tflint-plugin-sdk/tflint"
@@ -78,13 +80,53 @@ func (r *TerraformRequiredVersionRule) Check(runner tflint.Runner) error {
 		exists = exists || ok
 	}
 
-	if !exists {
-		return runner.EmitIssue(
-			r,
-			`terraform "required_version" attribute is required`,
-			hcl.Range{},
-		)
+	if exists {
+		return nil
+	}
+
+	if len(body.Blocks) > 0 {
+		return r.emitIssue(body.Blocks[0].DefRange, runner)
 	}
 
-	return nil
+	// If there are no "terraform" blocks, create a hcl.Range from the files
+	var file string
+	for k := range files {
+		file = k
+		break
+	}
+
+	// If there is only one file, use that
+	if len(files) == 1 {
+		return r.emitIssue(hcl.Range{
+			Filename: file,
+			Start:    hcl.InitialPos,
+		}, runner)
+	}
+
+	moduleDirectory := filepath.Dir(file)
+
+	// If there are multiple files, look for terraform.tf or main.tf (in that order)
+	for _, basename := range []string{"terraform.tf", "main.tf"} {
+		filename := filepath.Join(moduleDirectory, basename)
+		if _, ok := files[filename]; ok {
+			return r.emitIssue(hcl.Range{
+				Filename: filename,
+				Start:    hcl.InitialPos,
+			}, runner)
+		}
+	}
+
+	// If none of those are found, point to a nonexistent terraform.tf per the style guide
+	return r.emitIssue(hcl.Range{
+		Filename: filepath.Join(moduleDirectory, "terraform.tf"),
+	}, runner)
+}
+
+// emitIssue emits issue for missing terraform require version
+func (r *TerraformRequiredVersionRule) emitIssue(missingRange hcl.Range, runner tflint.Runner) error {
+	return runner.EmitIssue(
+		r,
+		`terraform "required_version" attribute is required`,
+		missingRange,
+	)
 }

rules/terraform_required_version_test.go

@@ -1,8 +1,10 @@
 package rules
 
 import (
+	"path/filepath"
 	"testing"
 
+	"github.com/hashicorp/hcl/v2"
 	"github.com/terraform-linters/tflint-plugin-sdk/helper"
 )
 
@@ -25,6 +27,17 @@ terraform {}
 				{
 					Rule:    NewTerraformRequiredVersionRule(),
 					Message: "terraform \"required_version\" attribute is required",
+					Range: hcl.Range{
+						Filename: "module.tf",
+						Start: hcl.Pos{
+							Line:   2,
+							Column: 1,
+						},
+						End: hcl.Pos{
+							Line:   2,
+							Column: 10,
+						},
+					},
 				},
 			},
 		},
@@ -53,6 +66,27 @@ terraform {
 `,
 			Expected: helper.Issues{},
 		},
+		{
+			Name: "no terraform block",
+			Content: `
+locals {
+	foo = "bar"
+}
+`,
+			Expected: helper.Issues{
+				{
+					Rule:    NewTerraformRequiredVersionRule(),
+					Message: "terraform \"required_version\" attribute is required",
+					Range: hcl.Range{
+						Filename: "module.tf",
+						Start: hcl.Pos{
+							Line:   1,
+							Column: 1,
+						},
+					},
+				},
+			},
+		},
 	}
 
 	rule := NewTerraformRequiredVersionRule()
@@ -73,3 +107,76 @@ terraform {
 		})
 	}
 }
+
+func Test_TerraformRequiredVersionRuleMultipleFiles(t *testing.T) {
+	cases := []struct {
+		Name     string
+		Files    []string
+		Expected helper.Issues
+	}{
+		{
+			Name:  "has terraform.tf and main.tf",
+			Files: []string{"modules/foo/main.tf", "modules/foo/terraform.tf"},
+			Expected: helper.Issues{
+				{
+					Rule:    NewTerraformRequiredVersionRule(),
+					Message: "terraform \"required_version\" attribute is required",
+					Range: hcl.Range{
+						Filename: filepath.FromSlash("modules/foo/terraform.tf"),
+						Start: hcl.Pos{
+							Line:   1,
+							Column: 1,
+						},
+					},
+				},
+			},
+		},
+		{
+			Name:  "has main.tf",
+			Files: []string{"modules/foo/outputs.tf", "modules/foo/main.tf", "modules/foo/variables.tf"},
+			Expected: helper.Issues{
+				{
+					Rule:    NewTerraformRequiredVersionRule(),
+					Message: "terraform \"required_version\" attribute is required",
+					Range: hcl.Range{
+						Filename: filepath.FromSlash("modules/foo/main.tf"),
+						Start: hcl.Pos{
+							Line:   1,
+							Column: 1,
+						},
+					},
+				},
+			},
+		},
+		{
+			Name:  "has neither terraform.tf or main.tf",
+			Files: []string{"modules/foo/variables.tf", "modules/foo/outputs.tf"},
+			Expected: helper.Issues{
+				{
+					Rule:    NewTerraformRequiredVersionRule(),
+					Message: "terraform \"required_version\" attribute is required",
+					Range: hcl.Range{
+						Filename: filepath.FromSlash("modules/foo/terraform.tf"),
+					},
+				},
+			},
+		},
+	}
+
+	rule := NewTerraformRequiredVersionRule()
+
+	for _, tc := range cases {
+		t.Run(tc.Name, func(t *testing.T) {
+			var files = map[string]string{}
+			for _, filename := range tc.Files {
+				files[filepath.FromSlash(filename)] = ""
+			}
+			runner := helper.TestRunner(t, files)
+			if err := rule.Check(runner); err != nil {
+				t.Fatal(err)
+			}
+
+			helper.AssertIssues(t, tc.Expected, runner.Issues)
+		})
+	}
+}