fix: disambiguate variable defaults with "empty" values from undefined

go.mod

@@ -12,3 +12,5 @@ require (
  github.com/stretchr/testify v1.3.0 // indirect
  github.com/zclconf/go-cty v1.1.0
 )
+
+go 1.13

tfconfig/load_hcl.go

@@ -149,6 +149,8 @@ func loadModule(dir string) (*Module, Diagnostics) {
  }
  v.Default = def
  }
+ } else {
+ v.Required = true
  }
 
  case "output":

tfconfig/load_legacy.go

@@ -102,6 +102,7 @@ func loadModuleLegacyHCL(dir string) (*Module, Diagnostics) {
  Type: block.Type,
  Description: block.Description,
  Default: block.Default,
+ Required: block.Default == nil,
  Pos: sourcePosLegacyHCL(item.Pos(), filename),
  }
  if _, exists := mod.Variables[name]; exists {

tfconfig/markdown.go

@@ -56,7 +56,7 @@ Provider Requirements:
 
 ## Input Variables
 {{- range .Variables }}
-* {{ tt .Name }}{{ if .Default }} (default {{ json .Default | tt }}){{else}} (required){{end}}
+* {{ tt .Name }}{{ if .Required }} (required){{else}} (default {{ json .Default | tt }}){{end}}
 {{- if .Description}}: {{ .Description }}{{ end }}
 {{- end}}{{end}}
 

tfconfig/testdata/basics-json/basics-json.out.json

@@ -7,6 +7,7 @@
  "A": {
  "name": "A",
  "default": "A default",
+ "required": false,
  "pos": {
  "filename": "testdata/basics-json/basics.tf.json",
  "line": 3
@@ -15,6 +16,8 @@
  "B": {
  "name": "B",
  "description": "The B variable",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/basics-json/basics.tf.json",
  "line": 6

tfconfig/testdata/basics/basics.out.json

@@ -7,6 +7,7 @@
  "A": {
  "name": "A",
  "default": "A default",
+ "required": false,
  "pos": {
  "filename": "testdata/basics/basics.tf",
  "line": 1
@@ -15,6 +16,8 @@
  "B": {
  "name": "B",
  "description": "The B variable",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/basics/basics.tf",
  "line": 5

tfconfig/testdata/for-expression/for-expression.out.json

@@ -11,28 +11,31 @@
  "one",
  "two",
  "three"
- ]
+ ],
+ "required": false
  },
  "enabled": {
  "name": "enabled",
  "pos": {
  "filename": "testdata/for-expression/for-expression.tf",
  "line": 4
  },
- "default": true
+ "default": true,
+ "required": false
  },
  "retention_days": {
  "name": "retention_days",
  "pos": {
  "filename": "testdata/for-expression/for-expression.tf",
  "line": 7
  },
- "default": 7
+ "default": 7,
+ "required": false
  }
  },
  "required_providers": {},
  "outputs": {},
  "managed_resources": {},
  "data_resources": {},
  "module_calls": {}
-}
+}

tfconfig/testdata/invalid-braces/invalid-braces.out.json

@@ -4,6 +4,7 @@
  "foo": {
  "name": "foo",
  "default": "123",
+ "required": false,
  "pos": {
  "filename": "testdata/invalid-braces/invalid-braces.tf",
  "line": 5

tfconfig/testdata/legacy-block-labels/legacy-block-labels.out.json

@@ -18,6 +18,7 @@
  "name": "foo",
  "description": "foo description",
  "default": "foo default",
+ "required": false,
  "pos": {
  "filename": "testdata/legacy-block-labels/legacy-block-labels.tf",
  "line": 29

tfconfig/testdata/overrides/overrides.out.json

@@ -7,6 +7,8 @@
  "A": {
  "name": "A",
  "description": "The A variable OVERRIDDEN",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/overrides/overrides_override.tf",
  "line": 1
@@ -15,6 +17,8 @@
  "B": {
  "name": "B",
  "description": "The B variable",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/overrides/overrides.tf",
  "line": 5
@@ -23,6 +27,8 @@
  "C": {
  "name": "C",
  "description": "An entirely new variable C",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/overrides/overrides_override.tf",
  "line": 5

tfconfig/testdata/type-conversions/type-conversions.out.json

@@ -21,6 +21,8 @@
  "name": "foo",
  "type": "true",
  "description": "true",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/type-conversions/type-conversions.tf",
  "line": 1

tfconfig/testdata/type-errors/type-errors.out.json

@@ -82,6 +82,8 @@
  "foo": {
  "name": "foo",
  "type": "{\"what\":\"the\"}",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/type-errors/type-errors.tf",
  "line": 1

tfconfig/testdata/variable-types/variable-types.out.json

@@ -6,6 +6,8 @@
  "variables": {
  "primitive": {
  "name": "primitive",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/variable-types/variable-types.tf",
  "line": 1
@@ -14,6 +16,8 @@
  "list": {
  "name": "list",
  "type": "list(string)",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/variable-types/variable-types.tf",
  "line": 4
@@ -22,6 +26,8 @@
  "list_json": {
  "name": "list_json",
  "type": "list(string)",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/variable-types/variable-types.tf.json",
  "line": 3
@@ -30,10 +36,72 @@
  "map": {
  "name": "map",
  "type": "map",
+ "default": null,
+ "required": true,
  "pos": {
  "filename": "testdata/variable-types/variable-types.tf",
  "line": 8
  }
+ },
+ "string_default_empty": {
+ "name": "string_default_empty",
+ "type": "string",
+ "default": "",
+ "required": false,
+ "pos": {
+ "filename": "testdata/variable-types/variable-types.tf",
+ "line": 14
+ }
+ },
+ "string_default_null": {
+ "name": "string_default_null",
+ "type": "string",
+ "default": null,
+ "required": false,
+ "pos": {
+ "filename": "testdata/variable-types/variable-types.tf",
+ "line": 19
+ }
+ },
+ "list_default_empty": {
+ "name": "list_default_empty",
+ "type": "list(string)",
+ "default": [],
+ "required": false,
+ "pos": {
+ "filename": "testdata/variable-types/variable-types.tf",
+ "line": 24
+ }
+ },
+ "object_default_empty": {
+ "name": "object_default_empty",
+ "type": "object({})",
+ "default": {},
+ "required": false,
+ "pos": {
+ "filename": "testdata/variable-types/variable-types.tf",
+ "line": 29
+ }
+ },
+ "number_default_zero": {
+ "name": "number_default_zero",
+ "type": "number",
+ "default": 0,
+ "required": false,
+ "pos": {
+ "filename": "testdata/variable-types/variable-types.tf",
+ "line": 34
+ }
+ },
+ "bool_default_false": {
+ "name": "bool_default_false",
+ "type": "bool",
+ "default": false,
+ "required": false,
+ "pos": {
+ "filename": "testdata/variable-types/variable-types.tf",
+ "line": 39
+ }
  }
  },
  "outputs": {},

tfconfig/testdata/variable-types/variable-types.out.md

@@ -2,8 +2,14 @@
 # Module `testdata/variable-types`
 
 ## Input Variables
+* `bool_default_false` (default `false`)
 * `list` (required)
+* `list_default_empty` (default `[]`)
 * `list_json` (required)
 * `map` (required)
+* `number_default_zero` (default `0`)
+* `object_default_empty` (default `{}`)
 * `primitive` (required)
+* `string_default_empty` (default `""`)
+* `string_default_null` (default `null`)
 

tfconfig/testdata/variable-types/variable-types.tf

@@ -10,3 +10,33 @@ variable "map" {
  # with older configurations.
  type = "map"
 }
+
+variable "string_default_empty" {
+ type = string
+ default = ""
+}
+
+variable "string_default_null" {
+ type = string
+ default = null
+}
+
+variable "list_default_empty" {
+ type = list(string)
+ default = []
+}
+
+variable "object_default_empty" {
+ type = object({})
+ default = {}
+}
+
+variable "number_default_zero" {
+ type = number
+ default = 0
+}
+
+variable "bool_default_false" {
+ type = bool
+ default = false
+}

tfconfig/variable.go

@@ -10,7 +10,8 @@ type Variable struct {
  // the native Go type system. The conversion from the value given in
  // configuration may be slightly lossy. Only values that can be
  // serialized by json.Marshal will be included here.
- Default interface{} `json:"default,omitempty"`
+ Default interface{} `json:"default"`
+ Required bool `json:"required"`
 
  Pos SourcePos `json:"pos"`
 }