feat(annotations): Allow a comment at the end of a tflint-ignore anno…

…tation (#1892)

Co-authored-by: Ben Drucker <bvdrucker@gmail.com>

docs/user-guide/annotations.md

@@ -26,3 +26,31 @@ resource "aws_instance" "foo" {
     instance_type = "t1.2xlarge"
 }
 ```
+
+It's a good idea to add a reason for why a rule is ignored, especially temporarily:
+
+```hcl
+resource "aws_instance" "foo" {
+    # This instance type is new and TFLint doesn't know about it yet
+    # tflint-ignore: aws_instance_invalid_type
+    instance_type = "t10.2xlarge"
+}
+```
+
+Or, on the same line:
+
+```hcl
+resource "aws_instance" "foo" {
+  # tflint-ignore: aws_instance_invalid_type # too new for TFLint
+  instance_type = "t10.2xlarge" 
+}
+```
+
+The `//` comment style is also supported, but Terraform recommends `#`.
+
+```hcl
+resource "aws_instance" "foo" {
+  // tflint-ignore: aws_instance_invalid_type // too new for TFLint
+  instance_type = "t10.2xlarge" 
+}
+```

tflint/annotation.go

@@ -10,7 +10,7 @@ import (
 	"github.com/hashicorp/hcl/v2/hclsyntax"
 )
 
-var annotationPattern = regexp.MustCompile(`tflint-ignore: ([^\n*/]+)`)
+var annotationPattern = regexp.MustCompile(`tflint-ignore: ([^\n*/#]+)`)
 
 // Annotation represents comments with special meaning in TFLint
 type Annotation struct {
@@ -40,7 +40,7 @@ func NewAnnotations(path string, file *hcl.File) (Annotations, hcl.Diagnostics)
 			continue
 		}
 		ret = append(ret, Annotation{
-			Content: match[1],
+			Content: strings.TrimSpace(match[1]),
 			Token:   token,
 		})
 	}

tflint/annotation_test.go

@@ -17,6 +17,9 @@ resource "aws_instance" "foo" {
   # tflint-ignore: aws_instance_invalid_type
   iam_instance_profile = "foo" # This is also comment
   // This is also comment
+  instance_type_reason = "t2.micro" // tflint-ignore: aws_instance_invalid_type // With reason
+  # tflint-ignore: aws_instance_invalid_type # With reason
+  iam_instance_profile_reason = "foo" # This is also comment
 }`
 
 	file, diags := hclsyntax.ParseConfig([]byte(src), "resource.tf", hcl.Pos{Byte: 0, Line: 1, Column: 1})
@@ -30,7 +33,7 @@ resource "aws_instance" "foo" {
 
 	expected := Annotations{
 		{
-			Content: "aws_instance_invalid_type, terraform_deprecated_syntax ",
+			Content: "aws_instance_invalid_type, terraform_deprecated_syntax",
 			Token: hclsyntax.Token{
 				Type:  hclsyntax.TokenComment,
 				Bytes: []byte("/* tflint-ignore: aws_instance_invalid_type, terraform_deprecated_syntax */"),
@@ -65,6 +68,30 @@ resource "aws_instance" "foo" {
 				},
 			},
 		},
+		{
+			Content: "aws_instance_invalid_type",
+			Token: hclsyntax.Token{
+				Type:  hclsyntax.TokenComment,
+				Bytes: []byte("// tflint-ignore: aws_instance_invalid_type // With reason\n"),
+				Range: hcl.Range{
+					Filename: "resource.tf",
+					Start:    hcl.Pos{Line: 8, Column: 37},
+					End:      hcl.Pos{Line: 9, Column: 1},
+				},
+			},
+		},
+		{
+			Content: "aws_instance_invalid_type",
+			Token: hclsyntax.Token{
+				Type:  hclsyntax.TokenComment,
+				Bytes: []byte("# tflint-ignore: aws_instance_invalid_type # With reason\n"),
+				Range: hcl.Range{
+					Filename: "resource.tf",
+					Start:    hcl.Pos{Line: 9, Column: 3},
+					End:      hcl.Pos{Line: 10, Column: 1},
+				},
+			},
+		},
 	}
 
 	opts := cmpopts.IgnoreFields(hcl.Pos{}, "Byte")