Revert^2 "Enforce that soong config variables are identifiers"

This reverts commit 149b5d003a.

Reason for revert: The variable that was causing issues before has been renamed

Change-Id: Ie0ffe9bf978332a2c921d21ccdf639b603fae39c

android/config.go

@@ -28,6 +28,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"unicode"
 
 	"github.com/google/blueprint"
 	"github.com/google/blueprint/bootstrap"
@@ -320,6 +321,18 @@ func loadConfig(config *config) error {
 	return loadFromConfigFile(&config.productVariables, absolutePath(config.ProductVariablesFileName))
 }
 
+// Checks if the string is a valid go identifier. This is equivalent to blueprint's definition
+// of an identifier, so it will match the same identifiers as those that can be used in bp files.
+func isGoIdentifier(ident string) bool {
+	for i, r := range ident {
+		valid := r == '_' || unicode.IsLetter(r) || unicode.IsDigit(r) && i > 0
+		if !valid {
+			return false
+		}
+	}
+	return len(ident) > 0
+}
+
 // loadFromConfigFile loads and decodes configuration options from a JSON file
 // in the current working directory.
 func loadFromConfigFile(configurable *ProductVariables, filename string) error {
@@ -355,6 +368,20 @@ func loadFromConfigFile(configurable *ProductVariables, filename string) error {
 		Bool(configurable.GcovCoverage) ||
 			Bool(configurable.ClangCoverage))
 
+	// The go scanner's definition of identifiers is c-style identifiers, but allowing unicode's
+	// definition of letters and digits. This is the same scanner that blueprint uses, so it
+	// will allow the same identifiers as are valid in bp files.
+	for namespace := range configurable.VendorVars {
+		if !isGoIdentifier(namespace) {
+			return fmt.Errorf("soong config namespaces must be valid identifiers: %q", namespace)
+		}
+		for variable := range configurable.VendorVars[namespace] {
+			if !isGoIdentifier(variable) {
+				return fmt.Errorf("soong config variables must be valid identifiers: %q", variable)
+			}
+		}
+	}
+
 	// when Platform_sdk_final is true (or PLATFORM_VERSION_CODENAME is REL), use Platform_sdk_version;
 	// if false (pre-released version, for example), use Platform_sdk_codename.
 	if Bool(configurable.Platform_sdk_final) {