Merge pull request #10628 from hashicorp/b-identifier

config: disallow names starting with ints

config/config.go

@@ -18,7 +18,7 @@ import (
 
 // NameRegexp is the regular expression that all names (modules, providers,
 // resources, etc.) must follow.
-var NameRegexp = regexp.MustCompile(`\A[A-Za-z0-9\-\_]+\z`)
+var NameRegexp = regexp.MustCompile(`(?i)\A[A-Z_][A-Z0-9\-\_]*\z`)
 
 // Config is the configuration that comes from loading a collection
 // of Terraform templates.
@@ -282,6 +282,14 @@ func (c *Config) Validate() error {
 		varMap[v.Name] = v
 	}
 
+	for k, _ := range varMap {
+		if !NameRegexp.MatchString(k) {
+			errs = append(errs, fmt.Errorf(
+				"variable %q: variable name must match regular expresion %s",
+				k, NameRegexp))
+		}
+	}
+
 	for _, v := range c.Variables {
 		if v.Type() == VariableTypeUnknown {
 			errs = append(errs, fmt.Errorf(

config/loader_hcl.go

@@ -404,6 +404,11 @@ func loadVariablesHcl(list *ast.ObjectList) ([]*Variable, error) {
 		}
 
 		n := item.Keys[0].Token.Value().(string)
+		if !NameRegexp.MatchString(n) {
+			return nil, fmt.Errorf(
+				"position %s: 'variable' name must match regular expression: %s",
+				item.Pos(), NameRegexp)
+		}
 
 		/*
 			// TODO: catch extra fields

config/loader_test.go

@@ -447,6 +447,20 @@ func TestLoadFile_variables(t *testing.T) {
 	}
 }
 
+func TestLoadFile_varInt(t *testing.T) {
+	_, err := LoadFile(filepath.Join(fixtureDir, "var_int.tf"))
+	if err == nil {
+		t.Fatal("should have error")
+	}
+}
+
+func TestLoadFile_varIntBare(t *testing.T) {
+	_, err := LoadFile(filepath.Join(fixtureDir, "var_int_bare.tf"))
+	if err == nil {
+		t.Fatal("should have error")
+	}
+}
+
 func TestLoadDir_basic(t *testing.T) {
 	dir := filepath.Join(fixtureDir, "dir-basic")
 	c, err := LoadDir(dir)

config/test-fixtures/var_int.tf

@@ -0,0 +1 @@
+variable "1x1" {}

config/test-fixtures/var_int_bare.tf

@@ -0,0 +1 @@
+variable 1x1 {}

website/source/upgrade-guides/0-8.html.markdown

@@ -57,6 +57,46 @@ EOF
 
 **Action:** Use heredocs or escape sequences when you have a string with newlines.
 
+## Names Cannot Start with Integers or Hyphens
+
+Names of variables, resources, modules, etc. may no longer start with
+numbers or hyphens. These will now fail at the validation step.
+
+This change was necessary to remove ambiguities from parsing the
+interpolations. Most languages do not allow identifiers starting with
+these characters with good reason. We now follow that as well.
+
+An example of a configuration that no longer works:
+
+```
+variable "1x1" {}
+```
+
+This must now be changed to start with a letter or underscore:
+
+```
+variable "foo-1x1" {}
+variable "_1x1" {}
+```
+
+And so on...
+
+If you're changing resource names, this can cause Terraform to consider it
+a new resource and plan to destroy it. To work around these scenarios,
+please use the `terraform state mv` command:
+
+```
+terraform state mv aws_instance.1x1 aws_instance.foo-1x1
+```
+
+The `terraform state mv` command creates a backup for each operation,
+but to be safe you can still back up your state prior to doing these
+changes.
+
+**Action:** Rename variable, resources, modules, providers, outputs that
+start with a number or hyphen. If you rename a resource or module, use
+`terraform state mv` to fix the state.
+
 ## Math Order of Operations
 
 Math operations now follow standard mathematical order of operations.