Specify an explicit locale for all to{Lower,Upper}Case calls

Java's `String#to{Lower,Upper}Case()` is locale-dependent, which can
lead to unexpected results in locales with special case mappings in the
ASCII range (e.g. in a Turkish locale, a capital ASCII `I` lowercases to
a non-ASCII variant of `i`).

This is prevented by specifying a local without such case mappings. This
commit uses `Locale.ROOT` as the canonical choice with the same case
mapping behavior as other common locales such as `Locale.ENGLISH` or
`Locale.US`.

Follow-up changes could use Guava's `Ascii.to{Lower,Upper}Case` instead,
but whether this is safe may depend on the context, which makes this
replacement unsuitable to perform across the repo.

Fixes bazelbuild#17541

src/java_tools/junitrunner/java/com/google/testing/junit/runner/util/TestIntegration.java

@@ -16,6 +16,7 @@
 
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import java.util.EnumMap;
+import java.util.Locale;
 import java.util.Map;
 
 /** TestIntegration represents an external link that is integrated with the test results. */
@@ -66,7 +67,7 @@ public enum ExternalLinkAttribute {
 
     /** Gets the string representation of the current enum. */
     public String getXmlAttributeName() {
-      return name().toLowerCase();
+      return name().toLowerCase(Locale.ROOT);
     }
   }
 

src/main/java/com/google/devtools/build/docgen/RuleDocumentation.java

@@ -18,6 +18,7 @@
 import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.docgen.DocgenConsts.RuleType;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
@@ -157,7 +158,7 @@ String getFamilySummary() {
    */
   @VisibleForTesting
   static String normalize(String s) {
-    return s.toLowerCase()
+    return s.toLowerCase(Locale.ROOT)
         .replace("+", "p")
         .replaceAll("[()]", "")
         .replaceAll("[\\s/]", "-")
@@ -298,12 +299,12 @@ public String getAttributeSignature() {
       if (attributeDoc.isCommonType()) {
         sb.append(String.format("<a href=\"%s#%s.%s\">%s</a>",
             COMMON_DEFINITIONS_PAGE,
-            attributeDoc.getGeneratedInRule(ruleName).toLowerCase(),
+            attributeDoc.getGeneratedInRule(ruleName).toLowerCase(Locale.ROOT),
             attrName,
             attrName));
       } else {
         sb.append(String.format("<a href=\"#%s.%s\">%s</a>",
-            attributeDoc.getGeneratedInRule(ruleName).toLowerCase(),
+            attributeDoc.getGeneratedInRule(ruleName).toLowerCase(Locale.ROOT),
             attrName,
             attrName));
       }
@@ -322,7 +323,7 @@ private String expandBuiltInVariables(String key, String value) {
     switch (key) {
       case DocgenConsts.VAR_IMPLICIT_OUTPUTS:
         return String.format("<h4 id=\"%s_implicit_outputs\">Implicit output targets</h4>\n%s",
-            ruleName.toLowerCase(), value);
+            ruleName.toLowerCase(Locale.ROOT), value);
       default:
         return value;
     }

src/main/java/com/google/devtools/build/docgen/RuleFamily.java

@@ -21,6 +21,7 @@
 import com.google.devtools.build.docgen.DocgenConsts.RuleType;
 import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
 import java.util.List;
+import java.util.Locale;
 
 /**
  * Helper class for representing a rule family in the rule summary table template.
@@ -71,7 +72,7 @@ public class RuleFamily {
    * "c-cpp".
    */
   static String normalize(String s) {
-    return FAMILY_NAME_ESCAPER.escape(s.toLowerCase()).replaceAll("[-]+", "-");
+    return FAMILY_NAME_ESCAPER.escape(s.toLowerCase(Locale.ROOT)).replaceAll("[-]+", "-");
   }
 
   public int size() {

src/main/java/com/google/devtools/build/docgen/StarlarkDocumentationProcessor.java

@@ -307,7 +307,7 @@ public String getDescription() {
     }
 
     public String getTemplateIdentifier() {
-      return name().toLowerCase().replace("_", "-");
+      return name().toLowerCase(Locale.ROOT).replace("_", "-");
     }
   }
 }

src/main/java/com/google/devtools/build/lib/actions/FilesetTraversalParamsFactory.java

@@ -46,7 +46,7 @@ public static SymlinkBehavior parse(String value) throws IllegalArgumentExceptio
 
     @Override
     public String toString() {
-      return super.toString().toLowerCase();
+      return super.toString().toLowerCase(Locale.ROOT);
     }
   }
 

src/main/java/com/google/devtools/build/lib/bazel/rules/android/AndroidNdkRepositoryFunction.java

@@ -58,6 +58,7 @@
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import javax.annotation.Nullable;
 import net.starlark.java.eval.EvalException;
@@ -514,7 +515,8 @@ private ImmutableList<String> generateBzlConfigFor(String version, CToolchain to
                 tp ->
                     String.format(
                         "  %s_path = '%s'",
-                        tp.getName().toLowerCase().replaceAll("-", "_"), tp.getPath()))
+                        tp.getName().toLowerCase(Locale.ROOT).replaceAll("-", "_"),
+                        tp.getPath()))
             .collect(ImmutableList.toImmutableList()));
     return bigConditional.add("").build();
   }

src/main/java/com/google/devtools/build/lib/bazel/rules/android/ndkcrosstools/StlImpl.java

@@ -20,6 +20,7 @@
 import com.google.devtools.build.lib.view.config.crosstool.CrosstoolConfig.CToolchain;
 import java.util.LinkedHashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import javax.annotation.Nullable;
 
@@ -36,9 +37,9 @@ private enum RuntimeType {
     private final String fileExtension;
 
     RuntimeType(String fileExtension) {
-      this.name = name().toLowerCase();
+      this.name = name().toLowerCase(Locale.ROOT);
       this.fileExtension = fileExtension;
-    }    
+    }
   }
 
   private final Map<String, String> fileGroupNameToFileGlobs = new LinkedHashMap<>();

src/main/java/com/google/devtools/build/lib/exec/local/XcodeLocalEnvProvider.java

@@ -29,6 +29,7 @@
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.nio.charset.StandardCharsets;
+import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
@@ -130,7 +131,7 @@ private static String querySdkRoot(
       String developerDir, String sdkVersion, String appleSdkPlatform)
       throws IOException, InterruptedException {
     try {
-      String sdkString = appleSdkPlatform.toLowerCase() + sdkVersion;
+      String sdkString = appleSdkPlatform.toLowerCase(Locale.ROOT) + sdkVersion;
       Map<String, String> env =
           Strings.isNullOrEmpty(developerDir)
               ? ImmutableMap.<String, String>of()
@@ -193,7 +194,7 @@ private static String getSdkRoot(String developerDir, String sdkVersion, String
       throws IOException, InterruptedException {
     try {
       return sdkRootCache.computeIfAbsent(
-          developerDir + ":" + appleSdkPlatform.toLowerCase() + ":" + sdkVersion,
+          developerDir + ":" + appleSdkPlatform.toLowerCase(Locale.ROOT) + ":" + sdkVersion,
           (key) -> {
             try {
               String sdkRoot = querySdkRoot(developerDir, sdkVersion, appleSdkPlatform);

src/main/java/com/google/devtools/build/lib/includescanning/IncludeParser.java

@@ -64,6 +64,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
+import java.util.Locale;
 import java.util.Set;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
@@ -120,7 +121,7 @@ private enum Type {
     final String findFilter;
 
     private Rule(String type, String pattern, String findRoot, String findFilter) {
-      this.type = Type.valueOf(type.trim().toUpperCase());
+      this.type = Type.valueOf(type.trim().toUpperCase(Locale.ROOT));
       this.pattern = Pattern.compile("^" + pattern + "$");
       this.findRoot = findRoot.replace('\\', '$');
       this.findFilter = findFilter;

src/main/java/com/google/devtools/build/lib/packages/EnumFilterConverter.java

@@ -19,6 +19,7 @@
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.LinkedHashSet;
+import java.util.Locale;
 import java.util.Set;
 
 /**
@@ -65,7 +66,7 @@ public Set<E> convert(String input) throws OptionsParsingException {
     EnumSet<E> excludedSet = EnumSet.noneOf(typeClass);
     for (String value : input.split(",", -1)) {
       boolean excludeFlag = value.startsWith("-");
-      String s = (excludeFlag ? value.substring(1) : value).toUpperCase();
+      String s = (excludeFlag ? value.substring(1) : value).toUpperCase(Locale.ROOT);
       if (!allowedValues.contains(s)) {
         throw new OptionsParsingException("Invalid " + prettyEnumName + " filter '" + value +
             "' in the input '" + input + "'");
@@ -91,6 +92,6 @@ public Set<E> convert(String input) throws OptionsParsingException {
   @Override
   public final String getTypeDescription() {
     return "comma-separated list of values: "
-        + StringUtil.joinEnglishList(allowedValues).toLowerCase();
+        + StringUtil.joinEnglishList(allowedValues).toLowerCase(Locale.ROOT);
   }
 }

src/main/java/com/google/devtools/build/lib/packages/License.java

@@ -210,9 +210,9 @@ public boolean isSpecified() {
   @Override
   public String toString() {
     if (exceptions.isEmpty()) {
-      return licenseTypes.toString().toLowerCase();
+      return licenseTypes.toString().toLowerCase(Locale.ROOT);
     } else {
-      return licenseTypes.toString().toLowerCase() + " with exceptions " + exceptions;
+      return licenseTypes.toString().toLowerCase(Locale.ROOT) + " with exceptions " + exceptions;
     }
   }
 

src/main/java/com/google/devtools/build/lib/packages/TestSize.java

@@ -16,6 +16,7 @@
 
 import com.google.common.collect.ImmutableMap;
 import com.google.devtools.common.options.OptionsParsingException;
+import java.util.Locale;
 import java.util.Set;
 import javax.annotation.Nullable;
 
@@ -41,7 +42,7 @@ public enum TestSize {
   static {
     ImmutableMap.Builder<String, TestSize> builder = ImmutableMap.builder();
     for (TestSize size : TestSize.values()) {
-      builder.put(size.name().toLowerCase(), size);
+      builder.put(size.name().toLowerCase(Locale.ROOT), size);
     }
     CANONICAL_LOWER_CASE_NAME_TABLE = builder.buildOrThrow();
   }
@@ -94,7 +95,7 @@ public static TestSize getTestSize(TestTimeout timeout) {
    */
   @Nullable
   public static TestSize getTestSize(String attr) {
-    if (!attr.equals(attr.toLowerCase())) {
+    if (!attr.equals(attr.toLowerCase(Locale.ROOT))) {
       return null;
     }
     try {
@@ -107,7 +108,7 @@ public static TestSize getTestSize(String attr) {
   /** Normal practice is to always use size tags as lower case strings. */
   @Override
   public String toString() {
-    return super.toString().toLowerCase();
+    return super.toString().toLowerCase(Locale.ROOT);
   }
 
   /**

src/main/java/com/google/devtools/build/lib/packages/TestTimeout.java

@@ -121,7 +121,7 @@ public enum TestTimeout {
    */
   @Nullable
   public static TestTimeout getTestTimeout(String attr) {
-    if (!attr.equals(attr.toLowerCase())) {
+    if (!attr.equals(attr.toLowerCase(Locale.ROOT))) {
       return null;
     }
     try {
@@ -138,7 +138,7 @@ public static TestTimeout getTestTimeout(String attr) {
   @Nullable
   public static TestTimeout getTestTimeout(Rule testTarget) {
     String attr = NonconfigurableAttributeMapper.of(testTarget).get("timeout", Type.STRING);
-    if (!attr.equals(attr.toLowerCase())) {
+    if (!attr.equals(attr.toLowerCase(Locale.ROOT))) {
       return null; // attribute values must be lowercase
     }
     try {
@@ -150,14 +150,14 @@ public static TestTimeout getTestTimeout(Rule testTarget) {
 
   @Override
   public String toString() {
-    return super.toString().toLowerCase();
+    return super.toString().toLowerCase(Locale.ROOT);
   }
 
   /**
    * We print to upper case to make the test timeout warnings more readable.
    */
   public String prettyPrint() {
-    return super.toString().toUpperCase();
+    return super.toString().toUpperCase(Locale.ROOT);
   }
 
   @Deprecated // use getTimeout instead

src/main/java/com/google/devtools/build/lib/remote/RemoteModule.java

@@ -112,6 +112,7 @@
 import java.net.URISyntaxException;
 import java.nio.channels.ClosedChannelException;
 import java.util.List;
+import java.util.Locale;
 import java.util.Optional;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -236,7 +237,7 @@ private static ServerCapabilities getAndVerifyServerCapabilities(
                   || status == HttpResponseStatus.SERVICE_UNAVAILABLE.code()
                   || status == HttpResponseStatus.GATEWAY_TIMEOUT.code();
         } else if (e instanceof IOException) {
-          String msg = e.getMessage().toLowerCase();
+          String msg = e.getMessage().toLowerCase(Locale.ROOT);
           if (msg.contains("connection reset by peer")) {
             retry = true;
           } else if (msg.contains("operation timed out")) {

src/main/java/com/google/devtools/build/lib/rules/android/AndroidConfiguration.java

@@ -39,6 +39,7 @@
 import com.google.devtools.common.options.OptionEffectTag;
 import com.google.devtools.common.options.OptionMetadataTag;
 import java.util.List;
+import java.util.Locale;
 import javax.annotation.Nullable;
 import net.starlark.java.eval.StarlarkValue;
 
@@ -165,9 +166,9 @@ public enum AndroidManifestMerger {
 
     public static List<String> getAttributeValues() {
       return ImmutableList.of(
-          LEGACY.name().toLowerCase(),
-          ANDROID.name().toLowerCase(),
-          FORCE_ANDROID.name().toLowerCase(),
+          LEGACY.name().toLowerCase(Locale.ROOT),
+          ANDROID.name().toLowerCase(Locale.ROOT),
+          FORCE_ANDROID.name().toLowerCase(Locale.ROOT),
           getRuleAttributeDefault());
     }
 

src/main/java/com/google/devtools/build/lib/rules/android/AndroidRuleClasses.java

@@ -58,6 +58,7 @@
 import com.google.devtools.build.lib.util.FileType;
 import com.google.devtools.build.lib.util.FileTypeSet;
 import java.util.List;
+import java.util.Locale;
 import javax.annotation.Nullable;
 import net.starlark.java.eval.StarlarkInt;
 
@@ -920,7 +921,7 @@ public enum MultidexMode {
 
     /** Returns the attribute value that specifies this mode. */
     public String getAttributeValue() {
-      return toString().toLowerCase();
+      return toString().toLowerCase(Locale.ROOT);
     }
 
     /**

src/main/java/com/google/devtools/build/lib/rules/android/WriteAdbArgsAction.java

@@ -33,6 +33,7 @@
 import java.io.PrintStream;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import javax.annotation.Nullable;
 
 /**
@@ -153,7 +154,7 @@ public void writeOutputFile(OutputStream out) throws IOException {
           ps.printf("--verbosity=%s\n", incrementalInstallVerbosity);
         }
 
-        ps.printf("--start=%s\n", start.name().toLowerCase());
+        ps.printf("--start=%s\n", start.name().toLowerCase(Locale.ROOT));
 
         if (userHomeDirectory != null) {
           ps.printf("--user_home_dir=%s\n", userHomeDirectory);

src/main/java/com/google/devtools/build/lib/rules/apple/AppleConfiguration.java

@@ -38,6 +38,7 @@
 import java.util.Arrays;
 import java.util.EnumMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import javax.annotation.Nullable;
 import net.starlark.java.eval.EvalException;
@@ -412,7 +413,7 @@ public Label getXcodeConfigLabel() {
   public String getOutputDirectoryName() {
     List<String> components = new ArrayList<>();
     if (!appleCpus.appleSplitCpu().isEmpty()) {
-      components.add(applePlatformType.toString().toLowerCase());
+      components.add(applePlatformType.toString().toLowerCase(Locale.ROOT));
       components.add(appleCpus.appleSplitCpu());
 
       if (options.getMinimumOsVersion() != null) {

src/main/java/com/google/devtools/build/lib/rules/apple/ApplePlatform.java

@@ -267,7 +267,7 @@ public boolean isImmutable() {
 
     @Override
     public String toString() {
-      return name().toLowerCase();
+      return name().toLowerCase(Locale.ROOT);
     }
 
     /**