From d07c17a47327394e4ee499068e37044dad50cb9c Mon Sep 17 00:00:00 2001
From: Mikkel Kjeldsen <commonquail@gmail.com>
Date: Tue, 25 Feb 2025 14:58:28 +0100
Subject: [PATCH] IdentifierName: accept regex to exempt type name violations

Occasionally, type names need to follow conventions that violate the
styleguide without being able to rely on inheritance or annotations for
exemption. For example, JMX MBean and MXBean definitions will routinely
violate the styleguide, and outside the JDK, `maven-failsafe-plugin`
3.5.2's default filter is a set of 3 violating patterns. Suppressing
these violations quickly becomes tedious.

Rather than Whac-A-Mole'ing tolerated violations, define a new option
whose value is a regex such that, if a possibly-violating type name
matches that regex, the type name is allowed anyway.

References: https://github.com/google/error-prone/issues/4776
References: https://github.com/google/error-prone/issues/4832
---
 .../errorprone/bugpatterns/IdentifierName.java    |  9 ++++++++-
 .../bugpatterns/IdentifierNameTest.java           | 15 +++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/IdentifierName.java b/core/src/main/java/com/google/errorprone/bugpatterns/IdentifierName.java
index 9b8e5cb14d5..3976965cbb1 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/IdentifierName.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/IdentifierName.java
@@ -60,6 +60,7 @@
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import com.sun.tools.javac.code.Symbol.VarSymbol;
 import com.sun.tools.javac.util.Name;
+import java.util.Optional;
 import java.util.regex.Pattern;
 import java.util.stream.Stream;
 import javax.inject.Inject;
@@ -103,10 +104,14 @@ public final class IdentifierName extends BugChecker
 
   private final boolean allowInitialismsInTypeName;
 
+  private final Pattern allowRegexInTypeName;
+
   @Inject
   IdentifierName(ErrorProneFlags flags) {
     this.allowInitialismsInTypeName =
         flags.getBoolean("IdentifierName:AllowInitialismsInTypeName").orElse(false);
+    this.allowRegexInTypeName =
+        Pattern.compile(flags.get("IdentifierName:AllowRegexInTypeName").orElse(".+"));
   }
 
   @Override
@@ -294,7 +299,9 @@ private static boolean isConformantLowerCamelName(String name) {
   private boolean isConformantTypeName(String name) {
     return !name.contains("_")
         && isUpperCase(name.charAt(0))
-        && (allowInitialismsInTypeName || !PROBABLE_INITIALISM.matcher(name).find());
+        && (allowInitialismsInTypeName
+            || allowRegexInTypeName.matcher(name).matches()
+            || !PROBABLE_INITIALISM.matcher(name).find());
   }
 
   private static boolean isStaticVariable(Symbol symbol) {
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/IdentifierNameTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/IdentifierNameTest.java
index 2e838b354b9..ecd9c943023 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/IdentifierNameTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/IdentifierNameTest.java
@@ -658,6 +658,21 @@ public void className_underscore() {
         .doTest();
   }
 
+  @Test
+  public void className_badPattern_allowed() {
+    helper
+        .setArgs("-XepOpt:IdentifierName:AllowRegexInTypeName=.+(IT|MX?Bean)")
+        .addSourceLines(
+            "SomethingMBean.java", //
+            "interface SomethingMBean {",
+            "}")
+        .addSourceLines(
+            "SomethingIT.java", //
+            "class SomethingIT {",
+            "}")
+        .doTest();
+  }
+
   @Test
   public void enumName() {
     helper