hhvm
diff --git a/.github/workflows/build-and-test.yml b/.github/workflows/build-and-test.yml
@@ -11,12 +11,11 @@ jobs:
       # Run tests on all OS's and HHVM versions, even if one fails
       fail-fast: false
       matrix:
-        os: [ ubuntu ]
+        os: [ ubuntu-20.04 ]
         hhvm:
-          - '4.128'
-          - latest
-          - nightly
-    runs-on: ${{matrix.os}}-latest
+          - '4.153'
+          - '4.168'
+    runs-on: ${{matrix.os}}
     steps:
       - uses: actions/checkout@v2
       - uses: hhvm/actions/hack-lint-test@master

diff --git a/composer.json b/composer.json
@@ -3,7 +3,7 @@
     "description": "Hack Codegen is a library for programmatically generating Hack code",
     "keywords": ["code generation", "Hack"],
     "require": {
-        "hhvm": "^4.128"
+        "hhvm": "^4.153"
     },
     "bin": [ "bin/hh-codegen-verify-signatures", "bin/hh-codegen-verify-signatures.hack" ],
     "authors": [

diff --git a/src/CodegenFile.hack b/src/CodegenFile.hack
@@ -32,8 +32,9 @@ enum CodegenFileType: int {
  * depending on whether there are manual sections.
  */
 final class CodegenFile {
+  const vec<string> LEGACY_FILE_SUFFIX_TRIGGERS = vec['.php', '.hh', '.hhi'];
 
-  private CodegenFileType $fileType = CodegenFileType::HACK_STRICT;
+  private CodegenFileType $fileType;
   private ?string $docBlock;
   private string $fileName;
   private string $relativeFileName;
@@ -63,6 +64,13 @@ final class CodegenFile {
     private IHackCodegenConfig $config,
     string $file_name,
   ) {
+    $this->fileType = C\any(
+      static::LEGACY_FILE_SUFFIX_TRIGGERS,
+      $t ==> Str\ends_with($file_name, $t),
+    )
+      ? CodegenFileType::HACK_STRICT
+      : CodegenFileType::DOT_HACK;
+
     $root = $config->getRootDir();
     if (!Str\starts_with($file_name, '/')) {
       $this->relativeFileName = $file_name;
@@ -186,6 +194,10 @@ final class CodegenFile {
     return $this->fileName;
   }
 
+  public function getFileType()[]: CodegenFileType {
+    return $this->fileType;
+  }
+
   public function getRelativeFileName(): string {
     return $this->relativeFileName;
   }

diff --git a/tests/CodegenFileTest.codegen b/tests/CodegenFileTest.codegen
@@ -1,13 +1,12 @@
 @generated
 !@#$%codegentest:testAutogenerated
-<?hh // strict
 // Codegen Tests
 /**
  * This file is generated. Do not modify it manually!
  *
  * Completely autogenerated!
  *
- * @-generated SignedSource<<e071d07d9cb3a77e37f24ecfc972a120>>
+ * @-generated SignedSource<<f8c58e9c529a492418b26efdeb95cd60>>
  */
 
 class AllAutogenerated {
@@ -18,12 +17,11 @@ class AllAutogenerated {
 }
 
 !@#$%codegentest:testConstants
-<?hh // strict
 // Codegen Tests
 /**
  * This file is generated. Do not modify it manually!
  *
- * @-generated SignedSource<<3081d5c20598b6bd1aa52a8035ffd207>>
+ * @-generated SignedSource<<30f984475edc103094e561bce9e9fdf0>>
  */
 namespace Foo\Bar;
 use namespace Herp\Derp;
@@ -67,11 +65,10 @@ function main(): void {
 main();
 
 !@#$%codegentest:testFormattingFullyGeneratedFile
-<?hh // strict
 /**
  * This file is generated. Do not modify it manually!
  *
- * @-generated SignedSource<<8873291d72dbb45b8a9e70890f7d2f0a>>
+ * @-generated SignedSource<<f78cdf7e9caaaaf7852fdf8330cf01e3>>
  */
 
 function my_func(
@@ -85,11 +82,10 @@ function my_func(
 }
 
 !@#$%codegentest:testFormattingFullyGeneratedFileWithOptions
-<?hh // strict
 /**
  * This file is generated. Do not modify it manually!
  *
- * @-generated SignedSource<<edb2ec6abbf7356621b98a5eac852996>>
+ * @-generated SignedSource<<f452b14a6164d435250f4c0088df8a86>>
  */
 
 function my_func(
@@ -103,11 +99,10 @@ function my_func(
 }
 
 !@#$%codegentest:testFormattingFullyGeneratedFileWithTabs
-<?hh // strict
 /**
  * This file is generated. Do not modify it manually!
  *
- * @-generated SignedSource<<763ad93f9a1a4caf70638a8de8786e49>>
+ * @-generated SignedSource<<f272aec490e6b17c15f61974e37838aa>>
  */
 
 function my_func(
@@ -118,12 +113,11 @@ function my_func(
 }
 
 !@#$%codegentest:testFormattingPartiallyGeneratedFile
-<?hh // strict
 /**
  * This file is partially generated. Only make modifications between BEGIN
  * MANUAL SECTION and END MANUAL SECTION designators.
  *
- * @-partially-generated SignedSource<<a6295bf3f813f9420063cf2da7478571>>
+ * @-partially-generated SignedSource<<3a7ef07d733ea4f3aa8c9d947d64c28e>>
  */
 
 function my_func(
@@ -139,7 +133,6 @@ function my_func(
 }
 
 !@#$%codegentest:testFormattingUnsignedFile
-<?hh // strict
 
 function my_func(
   string $aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,
@@ -152,12 +145,11 @@ function my_func(
 }
 
 !@#$%codegentest:testGenerateEnums
-<?hh // strict
 // Codegen Tests
 /**
  * This file is generated. Do not modify it manually!
  *
- * @-generated SignedSource<<9627a8d7e6cf7a65a9bf2ad85d657e03>>
+ * @-generated SignedSource<<4c9d48e406a74cd17064ea2ebcd0492f>>
  */
 
 
@@ -167,25 +159,23 @@ enum TestEnum : int {
 }
 
 !@#$%codegentest:testGenerateTopLevelFunctions
-<?hh // strict
 // Codegen Tests
 /**
  * This file is generated. Do not modify it manually!
  *
- * @-generated SignedSource<<36d9f7267f98197421aa97d0c84ca8f5>>
+ * @-generated SignedSource<<e081255cf9acdc95f2d7546affae7685>>
  */
 
 function fun(): int {
   return 0;
 }
 
 !@#$%codegentest:testNamespace
-<?hh // strict
 // Codegen Tests
 /**
  * This file is generated. Do not modify it manually!
  *
- * @-generated SignedSource<<962f609e88de287eef0d9c8eb42c6fce>>
+ * @-generated SignedSource<<1e82f55cc7df937c367b4936f57d25b3>>
  */
 namespace MyNamespace;
 use namespace Another\Space;
@@ -197,7 +187,6 @@ class Foo {
 }
 
 !@#$%codegentest:testNoSignature
-<?hh // strict
 // Codegen Tests
 /**
  * Completely autogenerated!
@@ -211,13 +200,12 @@ class NoSignature {
 }
 
 !@#$%codegentest:testPartiallyGenerated
-<?hh // strict
 // Codegen Tests
 /**
  * This file is partially generated. Only make modifications between BEGIN
  * MANUAL SECTION and END MANUAL SECTION designators.
  *
- * @-partially-generated SignedSource<<f45c8764e5eddd1d8ce7cb55633a7810>>
+ * @-partially-generated SignedSource<<4ac3ec3e124eaa6cf732ab42f6ecbc49>>
  */
 
 class PartiallyGenerated {
@@ -248,14 +236,13 @@ class Foo {
 }
 
 !@#$%codegentest:testSaveAutogenerated
-<?hh // strict
 // Codegen Tests
 /**
  * This file is generated. Do not modify it manually!
  *
  * Testing CodegenFile with autogenerated files
  *
- * @-generated SignedSource<<6a105a3097cde1632d78096f693751c6>>
+ * @-generated SignedSource<<624100da9e208d6abeaa301bce015bfd>>
  */
 
 class Demo {
@@ -266,15 +253,14 @@ class Demo {
 }
 
 !@#$%codegentest:testSavePartiallyGenerated
-<?hh // strict
 // Codegen Tests
 /**
  * This file is partially generated. Only make modifications between BEGIN
  * MANUAL SECTION and END MANUAL SECTION designators.
  *
  * Testing CodegenFile with partially generated files
  *
- * @-partially-generated SignedSource<<500fa4945d39860935bb0c92a72477a0>>
+ * @-partially-generated SignedSource<<e0a4ec17c8e71c803d34407363ca8af6>>
  */
 
 class Demo {
@@ -287,12 +273,11 @@ class Demo {
 }
 
 !@#$%codegentest:testStrictFile
-<?hh // strict
 // Codegen Tests
 /**
  * This file is generated. Do not modify it manually!
  *
- * @-generated SignedSource<<5c0182dcd097a22f08d4dfbcc555c52c>>
+ * @-generated SignedSource<<d1d6954e25b8c7fb2bf045bede5f356b>>
  */
 
 class Foo {