Remove --no_ support.

--no_ prefixes for boolean flags are deprecated. Error out nicely if --no_ is supplied.
PiperOrigin-RevId: 152434290

2 files changed, 16 insertions, 9 deletions

diff --git a/src/main/java/com/google/devtools/common/options/IsolatedOptionsData.java b/src/main/java/com/google/devtools/common/options/IsolatedOptionsData.java
index 5074b99bf5..084daaddc8 100644
--- a/src/main/java/com/google/devtools/common/options/IsolatedOptionsData.java
+++ b/src/main/java/com/google/devtools/common/options/IsolatedOptionsData.java
@@ -294,13 +294,10 @@ public class IsolatedOptionsData extends OpaqueOptionsData {
       Map<String, Field> nameToFieldMap,
       Map<String, String> booleanAliasMap,
       String optionName) {
-    // Check that the two aliases do not conflict with existing flags.
-    checkForCollisions(nameToFieldMap, "no_" + optionName, "boolean option alias");
+    // Check that the negating alias does not conflict with existing flags.
     checkForCollisions(nameToFieldMap, "no" + optionName, "boolean option alias");
 
-    // Record that the boolean option takes up additional namespace for its two negating
-    // aliases.
-    booleanAliasMap.put("no_" + optionName, optionName);
+    // Record that the boolean option takes up additional namespace for its negating alias.
     booleanAliasMap.put("no" + optionName, optionName);
   }
   
diff --git a/src/main/java/com/google/devtools/common/options/OptionsParserImpl.java b/src/main/java/com/google/devtools/common/options/OptionsParserImpl.java
index fd3a8cea13..8394d07c2e 100644
--- a/src/main/java/com/google/devtools/common/options/OptionsParserImpl.java
+++ b/src/main/java/com/google/devtools/common/options/OptionsParserImpl.java
@@ -641,11 +641,21 @@ class OptionsParserImpl {
       value = equalsAt == -1 ? null : arg.substring(equalsAt + 1);
       field = optionsData.getFieldFromName(name);
 
-      // Look for a "no"-prefixed option name: "no<optionName>" or "no_<optionName>".
-      // Note: It is impossible to specify "--no_foo" for a flag named "--_foo", since that'll be
-      // interpreted as the "no_" negating prefix for "--foo".
+      // Look for a "no"-prefixed option name: "no<optionName>".
       if (field == null && name.startsWith("no")) {
-        name = name.substring(name.startsWith("no_") ? 3 : 2);
+        // Give a nice error if someone is using the deprecated --no_ prefix.
+        // Note: With this check in place, is impossible to specify "--no_foo" for a flag named
+        // "--_foo", if a --foo flag also exists, since that'll be interpreted as the "no_"
+        // negating prefix for "--foo". Let that be a warning to anyone wanting to make flags that
+        // start with underscores.
+        // TODO(Bazel-team): Remove the --no_ check when sufficient time has passed for users of
+        // that feature to have stopped using it.
+        if (name.startsWith("no_") && optionsData.getFieldFromName(name.substring(3)) != null) {
+          throw new OptionsParsingException(
+              "'no_' prefixes are no longer accepted, --no<flag> is an accepted alternative.",
+              name.substring(3));
+        }
+        name = name.substring(2);
         field = optionsData.getFieldFromName(name);
         booleanValue = false;
         if (field != null) {