From 9653b20e28132cad3887fcf22368104b2e27e994 Mon Sep 17 00:00:00 2001
From: Rory <rory.elrick@gmail.com>
Date: Wed, 8 Sep 2021 11:33:15 +1000
Subject: [PATCH] Adding command line flag for
 setAssumeStaticInheritanceRequired, fix for #3559

---
 .../google/javascript/jscomp/CommandLineRunner.java    | 10 ++++++++++
 .../javascript/jscomp/CommandLineRunnerTest.java       |  9 +++++++++
 2 files changed, 19 insertions(+)

diff --git a/src/com/google/javascript/jscomp/CommandLineRunner.java b/src/com/google/javascript/jscomp/CommandLineRunner.java
index b2445a836ef..3a979e02acc 100644
--- a/src/com/google/javascript/jscomp/CommandLineRunner.java
+++ b/src/com/google/javascript/jscomp/CommandLineRunner.java
@@ -930,6 +930,14 @@ private static class Flags {
                 + "An alias of 'import' is allowed.")
     private String dynamicImportAlias = null;
 
+    @Option(
+            name = "--assume_static_inheritance_required",
+            handler = BooleanOptionHandler.class,
+            usage =
+                "Instructs the compiler not to perform potential breaking optimizations "
+                  + "when the code being compiled depends on static inheritance."  )
+    private boolean assumeStaticInheritanceRequired = false;
+
     @Argument private List<String> arguments = new ArrayList<>();
     private final CmdLineParser parser;
 
@@ -1042,6 +1050,7 @@ private void parse(List<String> args) throws CmdLineException {
                     "json_streams",
                     "third_party",
                     "use_types_for_optimization",
+                    "assume_static_inheritance_required",
                     "version"))
             .build();
 
@@ -1982,6 +1991,7 @@ protected CompilerOptions createOptions() {
     options.setProductionInstrumentationArrayName(flags.productionInstrumentationArrayName);
     options.setAllowDynamicImport(flags.allowDynamicImport);
     options.setDynamicImportAlias(flags.dynamicImportAlias);
+    options.setAssumeStaticInheritanceRequired(flags.assumeStaticInheritanceRequired);
 
     if (flags.chunkOutputType == ChunkOutputType.ES_MODULES) {
       if (flags.renamePrefixNamespace != null) {
diff --git a/test/com/google/javascript/jscomp/CommandLineRunnerTest.java b/test/com/google/javascript/jscomp/CommandLineRunnerTest.java
index 8eff3bf4adc..307beff854a 100644
--- a/test/com/google/javascript/jscomp/CommandLineRunnerTest.java
+++ b/test/com/google/javascript/jscomp/CommandLineRunnerTest.java
@@ -2926,6 +2926,15 @@ public void testChunkOutputFiles() throws IOException {
     assertThat(weakFile.exists()).isFalse();
   }
 
+  @Test
+  public void testAssumeStaticInheritanceRequired() {
+    testSame("");
+    assertThat(lastCompiler.getOptions().getAssumeStaticInheritanceRequired()).isFalse();
+    args.add("--assume_static_inheritance_required");
+    testSame("");
+    assertThat(lastCompiler.getOptions().getAssumeStaticInheritanceRequired()).isTrue();
+  }
+
   /* Helper functions */
 
   private void testSame(String original) {