soong_config: bool_variables shortcut

Using a lot of boolean variables can become very verbose without adding
really any new information:

      variables: ["a", "b", "c"],
  }

  soong_config_bool_variable {
      name: "a",
  }

  soong_config_bool_variable {
      name: "b",
  }

  soong_config_bool_variable {
      name: "c",
  }

Now turns into:

      bool_variables: ["a", "b", "c"],
  }

Test: built-in tests
Change-Id: If5455a38433431c7ecbce1e5b32cfbb47f42602a
diff --git a/README.md b/README.md
index b1bb425..3eac87b 100644
--- a/README.md
+++ b/README.md
@@ -419,7 +419,8 @@
     name: "acme_cc_defaults",
     module_type: "cc_defaults",
     config_namespace: "acme",
-    variables: ["board", "feature"],
+    variables: ["board"],
+    bool_variables: ["feature"],
     properties: ["cflags", "srcs"],
 }
 
@@ -427,10 +428,6 @@
     name: "board",
     values: ["soc_a", "soc_b"],
 }
-
-soong_config_bool_variable {
-    name: "feature",
-}
 ```
 
 This example describes a new `acme_cc_defaults` module type that extends the
diff --git a/android/soong_config_modules.go b/android/soong_config_modules.go
index 198108d..fa1e204 100644
--- a/android/soong_config_modules.go
+++ b/android/soong_config_modules.go
@@ -88,7 +88,8 @@
 //         name: "acme_cc_defaults",
 //         module_type: "cc_defaults",
 //         config_namespace: "acme",
-//         variables: ["board", "feature"],
+//         variables: ["board"],
+//         bool_variables: ["feature"],
 //         properties: ["cflags", "srcs"],
 //     }
 //
@@ -97,10 +98,6 @@
 //         values: ["soc_a", "soc_b"],
 //     }
 //
-//     soong_config_bool_variable {
-//         name: "feature",
-//     }
-//
 // If an acme BoardConfig.mk file contained:
 //
 //     SOONG_CONFIG_NAMESPACES += acme
@@ -149,7 +146,8 @@
 //         name: "acme_cc_defaults",
 //         module_type: "cc_defaults",
 //         config_namespace: "acme",
-//         variables: ["board", "feature"],
+//         variables: ["board"],
+//         bool_variables: ["feature"],
 //         properties: ["cflags", "srcs"],
 //     }
 //
@@ -158,10 +156,6 @@
 //         values: ["soc_a", "soc_b"],
 //     }
 //
-//     soong_config_bool_variable {
-//         name: "feature",
-//     }
-//
 //     acme_cc_defaults {
 //         name: "acme_defaults",
 //         cflags: ["-DGENERIC"],
diff --git a/android/soong_config_modules_test.go b/android/soong_config_modules_test.go
index 6ad88a2..1cf060d 100644
--- a/android/soong_config_modules_test.go
+++ b/android/soong_config_modules_test.go
@@ -43,7 +43,8 @@
 			name: "acme_test_defaults",
 			module_type: "test_defaults",
 			config_namespace: "acme",
-			variables: ["board", "feature1", "feature2", "FEATURE3"],
+			variables: ["board", "feature1", "FEATURE3"],
+			bool_variables: ["feature2"],
 			properties: ["cflags", "srcs"],
 		}
 
@@ -57,10 +58,6 @@
 		}
 
 		soong_config_bool_variable {
-			name: "feature2",
-		}
-
-		soong_config_bool_variable {
 			name: "FEATURE3",
 		}
 	`
diff --git a/android/soongconfig/modules.go b/android/soongconfig/modules.go
index aa4f5c5..2d6063d 100644
--- a/android/soongconfig/modules.go
+++ b/android/soongconfig/modules.go
@@ -109,6 +109,9 @@
 	// the list of SOONG_CONFIG variables that this module type will read
 	Variables []string
 
+	// the list of boolean SOONG_CONFIG variables that this module type will read
+	Bool_variables []string
+
 	// the list of properties that this module type will extend.
 	Properties []string
 }
@@ -146,6 +149,18 @@
 	}
 	v.ModuleTypes[props.Name] = mt
 
+	for _, name := range props.Bool_variables {
+		if name == "" {
+			return []error{fmt.Errorf("bool_variable name must not be blank")}
+		}
+
+		mt.Variables = append(mt.Variables, &boolVariable{
+			baseVariable: baseVariable{
+				variable: name,
+			},
+		})
+	}
+
 	return nil
 }
 
diff --git a/bpfix/bpfix/bpfix.go b/bpfix/bpfix/bpfix.go
index 0516279..a1c5de1 100644
--- a/bpfix/bpfix/bpfix.go
+++ b/bpfix/bpfix/bpfix.go
@@ -124,6 +124,10 @@
 		Name: "removeHidlInterfaceTypes",
 		Fix:  removeHidlInterfaceTypes,
 	},
+	{
+		Name: "removeSoongConfigBoolVariable",
+		Fix:  removeSoongConfigBoolVariable,
+	},
 }
 
 func NewFixRequest() FixRequest {
@@ -714,6 +718,78 @@
 	return nil
 }
 
+func removeSoongConfigBoolVariable(f *Fixer) error {
+	found := map[string]bool{}
+	newDefs := make([]parser.Definition, 0, len(f.tree.Defs))
+	for _, def := range f.tree.Defs {
+		if mod, ok := def.(*parser.Module); ok && mod.Type == "soong_config_bool_variable" {
+			if name, ok := getLiteralStringPropertyValue(mod, "name"); ok {
+				found[name] = true
+			} else {
+				return fmt.Errorf("Found soong_config_bool_variable without a name")
+			}
+		} else {
+			newDefs = append(newDefs, def)
+		}
+	}
+	f.tree.Defs = newDefs
+
+	if len(found) == 0 {
+		return nil
+	}
+
+	return runPatchListMod(func(mod *parser.Module, buf []byte, patchList *parser.PatchList) error {
+		if mod.Type != "soong_config_module_type" {
+			return nil
+		}
+
+		variables, ok := getLiteralListProperty(mod, "variables")
+		if !ok {
+			return nil
+		}
+
+		boolValues := strings.Builder{}
+		empty := true
+		for _, item := range variables.Values {
+			nameValue, ok := item.(*parser.String)
+			if !ok {
+				empty = false
+				continue
+			}
+			if found[nameValue.Value] {
+				patchList.Add(item.Pos().Offset, item.End().Offset+2, "")
+
+				boolValues.WriteString(`"`)
+				boolValues.WriteString(nameValue.Value)
+				boolValues.WriteString(`",`)
+			} else {
+				empty = false
+			}
+		}
+		if empty {
+			*patchList = parser.PatchList{}
+
+			prop, _ := mod.GetProperty("variables")
+			patchList.Add(prop.Pos().Offset, prop.End().Offset+2, "")
+		}
+		if boolValues.Len() == 0 {
+			return nil
+		}
+
+		bool_variables, ok := getLiteralListProperty(mod, "bool_variables")
+		if ok {
+			patchList.Add(bool_variables.RBracePos.Offset, bool_variables.RBracePos.Offset, ","+boolValues.String())
+		} else {
+			patchList.Add(variables.RBracePos.Offset+2, variables.RBracePos.Offset+2,
+				fmt.Sprintf(`bool_variables: [%s],`, boolValues.String()))
+		}
+
+		return nil
+	})(f)
+
+	return nil
+}
+
 // Converts the default source list property, 'srcs', to a single source property with a given name.
 // "LOCAL_MODULE" reference is also resolved during the conversion process.
 func convertToSingleSource(mod *parser.Module, srcPropertyName string) {
diff --git a/bpfix/bpfix/bpfix_test.go b/bpfix/bpfix/bpfix_test.go
index 38cefdd..64a7b93 100644
--- a/bpfix/bpfix/bpfix_test.go
+++ b/bpfix/bpfix/bpfix_test.go
@@ -918,3 +918,67 @@
 		})
 	}
 }
+
+func TestRemoveSoongConfigBoolVariable(t *testing.T) {
+	tests := []struct {
+		name string
+		in   string
+		out  string
+	}{
+		{
+			name: "remove bool",
+			in: `
+				soong_config_module_type {
+					name: "foo",
+					variables: ["bar", "baz"],
+				}
+
+				soong_config_bool_variable {
+					name: "bar",
+				}
+
+				soong_config_string_variable {
+					name: "baz",
+				}
+			`,
+			out: `
+				soong_config_module_type {
+					name: "foo",
+					variables: [
+						"baz"
+					],
+					bool_variables: ["bar"],
+				}
+
+				soong_config_string_variable {
+					name: "baz",
+				}
+			`,
+		},
+		{
+			name: "existing bool_variables",
+			in: `
+				soong_config_module_type {
+					name: "foo",
+					variables: ["baz"],
+					bool_variables: ["bar"],
+				}
+
+				soong_config_bool_variable {
+					name: "baz",
+				}
+			`,
+			out: `
+				soong_config_module_type {
+					name: "foo",
+					bool_variables: ["bar", "baz"],
+				}
+			`,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			runPass(t, test.in, test.out, removeSoongConfigBoolVariable)
+		})
+	}
+}