Add terraform-tflint checker

CHANGES.rst

@@ -33,6 +33,7 @@
   - VHDL with ``ghdl`` [GH-1160]
   - mypy with ``python-mypy`` [GH-1354]
   - terraform with ``terraform fmt`` [GH-1586]
+  - terraform-tflint with ``tflint`` [GH-1586]
 
 - New features:
 

doc/languages.rst

@@ -1378,6 +1378,10 @@ to view the docstring of the syntax checker.  Likewise, you may use
 
       .. _terraform fmt: https://www.terraform.io/docs/commands/fmt.html
 
+   .. syntax-checker:: terraform-tflint
+
+      Check Terraform with `tflint <https://github.com/wata727/tflint>`_
+
 .. supported-language:: Text
 
    .. syntax-checker:: proselint

flycheck.el

@@ -262,6 +262,7 @@ attention to case differences."
     systemd-analyze
     tcl-nagelfar
     terraform
+    terraform-tflint
     tex-chktex
     tex-lacheck
     texinfo
@@ -10770,6 +10771,40 @@ See URL `https://www.terraform.io/docs/commands/fmt.html'."
           "\n\n  on <stdin> line " line ":\n  (source code not available)\n\n"
           (message (one-or-more (and (one-or-more (not (any ?\n))) ?\n)))
           line-end))
+  :next-checkers ((warning . terraform-tflint))
+  :modes terraform-mode)
+
+(defun flycheck-parse-tflint-linter (output checker buffer)
+  "Parse tflint warnings from JSON OUTPUT.
+
+CHECKER and BUFFER denote the CHECKER that returned OUTPUT and
+the BUFFER that was checked respectively.
+
+See URL `https://github.com/wata727/tflint' for more
+information about tflint."
+  (mapcar (lambda (err)
+            (let-alist err
+              (flycheck-error-new-at
+               .line
+               nil
+               (pcase .type
+                 (`"ERROR"   'error)
+                 (`"WARNING" 'warning)
+                 ;; Default to error
+                 (_          'error))
+               .message
+               :id .detector
+               :checker checker
+               :buffer buffer
+               :filename (buffer-file-name buffer))))
+          (car (flycheck-parse-json output))))
+
+(flycheck-define-checker terraform-tflint
+  "A Terraform checker using tflint.
+
+See URL `https://github.com/wata727/tflint'."
+  :command ("tflint" "--error-with-issues" "--format=json" source)
+  :error-parser flycheck-parse-tflint-linter
   :modes terraform-mode)
 
 (flycheck-define-checker tex-chktex

test/flycheck-test.el

@@ -4089,6 +4089,12 @@ Why not:
    '(2 nil error "An argument definition must end with a newline."
        :checker terraform)))
 
+(flycheck-ert-def-checker-test terraform-tflint terraform nil
+  (flycheck-ert-should-syntax-check
+   "language/terraform/error.tf" 'terraform-mode
+   '(3 nil error "\"t1.2xlarge\" is invalid instance type."
+       :id "aws_instance_invalid_type" :checker terraform-tflint)))
+
 (flycheck-ert-def-checker-test markdown-markdownlint-cli markdown nil
   (flycheck-ert-should-syntax-check
    "language/markdown.md" 'markdown-mode

test/resources/language/terraform/error.tf

@@ -0,0 +1,4 @@
+resource "aws_instance" "web" {
+  ami           = "ami-b73b63a0"
+  instance_type = "t1.2xlarge" # invalid type
+}