From 861377b3ec352e48fc981cde25903c454972267f Mon Sep 17 00:00:00 2001
From: Liam Miller-Cushon <cushon@google.com>
Date: Fri, 24 Mar 2023 16:09:16 -0700
Subject: [PATCH] Use LinkedHashMap to keep track of severities

The order of these entries became significant after https://github.com/google/error-prone/commit/48bbef0e51c2f5098efe6a2587fafc0ebc31bca5, which
allowed using -Xep flags to configure checks using alt names.

https://github.com/google/error-prone/issues/3831

PiperOrigin-RevId: 519261645
---
 .../google/errorprone/ErrorProneOptions.java  |  4 ++--
 .../errorprone/ErrorProneOptionsTest.java     | 20 +++++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/check_api/src/main/java/com/google/errorprone/ErrorProneOptions.java b/check_api/src/main/java/com/google/errorprone/ErrorProneOptions.java
index ca9d9a5541e..f60c1ce85dc 100644
--- a/check_api/src/main/java/com/google/errorprone/ErrorProneOptions.java
+++ b/check_api/src/main/java/com/google/errorprone/ErrorProneOptions.java
@@ -31,7 +31,7 @@
 import java.nio.file.FileSystems;
 import java.nio.file.Files;
 import java.util.Arrays;
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.regex.Pattern;
@@ -259,7 +259,7 @@ private static class Builder {
     private boolean isTestOnlyTarget = false;
     private boolean ignoreSuppressionAnnotations = false;
     private boolean ignoreLargeCodeGenerators = true;
-    private Map<String, Severity> severityMap = new HashMap<>();
+    private final Map<String, Severity> severityMap = new LinkedHashMap<>();
     private final ErrorProneFlags.Builder flagsBuilder = ErrorProneFlags.builder();
     private final PatchingOptions.Builder patchingOptionsBuilder = PatchingOptions.builder();
     private Pattern excludedPattern;
diff --git a/check_api/src/test/java/com/google/errorprone/ErrorProneOptionsTest.java b/check_api/src/test/java/com/google/errorprone/ErrorProneOptionsTest.java
index 6c73bf63aa3..80903468aef 100644
--- a/check_api/src/test/java/com/google/errorprone/ErrorProneOptionsTest.java
+++ b/check_api/src/test/java/com/google/errorprone/ErrorProneOptionsTest.java
@@ -16,13 +16,18 @@
 
 package com.google.errorprone;
 
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertThrows;
 
+import com.google.common.collect.Collections2;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.errorprone.ErrorProneOptions.Severity;
 import com.google.errorprone.apply.ImportOrganizer;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
 import java.util.regex.Pattern;
 import org.junit.Test;
@@ -276,4 +281,19 @@ public void noSuchXepFlag() {
         InvalidCommandLineOptionException.class,
         () -> ErrorProneOptions.processArgs(new String[] {"-XepNoSuchFlag"}));
   }
+
+  @Test
+  public void severityOrder() {
+    for (Collection<String> permutation :
+        Collections2.permutations(ImmutableList.of("A", "B", "C"))) {
+      ImmutableMap<String, Severity> severityMap =
+          permutation.stream().collect(toImmutableMap(x -> x, x -> Severity.ERROR));
+      ErrorProneOptions options =
+          ErrorProneOptions.processArgs(
+              permutation.stream()
+                  .map(x -> String.format("-Xep:%s:ERROR", x))
+                  .collect(toImmutableList()));
+      assertThat(options.getSeverityMap()).containsExactlyEntriesIn(severityMap).inOrder();
+    }
+  }
 }