From 83d878d34ce9e9677bb95a02013b1376391c14cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nribaudo@igalia.com>
Date: Thu, 9 May 2024 15:05:11 +0200
Subject: [PATCH 1/2] Rename builder esprima fixtures to babel

f724ae98a1c0859885083448e2cbc3f3d4c31cf1 changed the build
script to use Babel, so this commit updates the file names accordingly
---
 .eslintignore                                                 | 2 +-
 .prettierignore                                               | 2 +-
 .stylelintignore                                              | 2 +-
 .../{fixtures_esprima => fixtures_babel}/blocks-expected.js   | 0
 .../builder/{fixtures_esprima => fixtures_babel}/blocks.js    | 0
 .../{fixtures_esprima => fixtures_babel}/comments-expected.js | 0
 .../builder/{fixtures_esprima => fixtures_babel}/comments.js  | 0
 .../constants-expected.js                                     | 0
 .../builder/{fixtures_esprima => fixtures_babel}/constants.js | 0
 .../{fixtures_esprima => fixtures_babel}/deadcode-expected.js | 0
 .../builder/{fixtures_esprima => fixtures_babel}/deadcode.js  | 0
 .../{fixtures_esprima => fixtures_babel}/evals-expected.js    | 0
 .../builder/{fixtures_esprima => fixtures_babel}/evals.js     | 2 +-
 .../builder/{fixtures_esprima => fixtures_babel}/evals.json   | 0
 .../{fixtures_esprima => fixtures_babel}/ifs-expected.js      | 0
 external/builder/{fixtures_esprima => fixtures_babel}/ifs.js  | 0
 .../importalias-expected.js                                   | 0
 .../{fixtures_esprima => fixtures_babel}/importalias.js       | 0
 .../{test-fixtures_esprima.mjs => test-fixtures_babel.mjs}    | 4 ++--
 gulpfile.mjs                                                  | 4 ++--
 20 files changed, 8 insertions(+), 8 deletions(-)
 rename external/builder/{fixtures_esprima => fixtures_babel}/blocks-expected.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/blocks.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/comments-expected.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/comments.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/constants-expected.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/constants.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/deadcode-expected.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/deadcode.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/evals-expected.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/evals.js (85%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/evals.json (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/ifs-expected.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/ifs.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/importalias-expected.js (100%)
 rename external/builder/{fixtures_esprima => fixtures_babel}/importalias.js (100%)
 rename external/builder/{test-fixtures_esprima.mjs => test-fixtures_babel.mjs} (93%)

diff --git a/.eslintignore b/.eslintignore
index 31317afd2..a1279de75 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -4,7 +4,7 @@ docs/
 node_modules/
 external/bcmaps/
 external/builder/fixtures/
-external/builder/fixtures_esprima/
+external/builder/fixtures_babel/
 external/quickjs/
 external/openjpeg/
 test/tmp/
diff --git a/.prettierignore b/.prettierignore
index 05172be1e..e33594bd7 100644
--- a/.prettierignore
+++ b/.prettierignore
@@ -4,7 +4,7 @@ docs/
 node_modules/
 external/bcmaps/
 external/builder/fixtures/
-external/builder/fixtures_esprima/
+external/builder/fixtures_babel/
 external/quickjs/
 test/tmp/
 test/pdfs/
diff --git a/.stylelintignore b/.stylelintignore
index 05172be1e..e33594bd7 100644
--- a/.stylelintignore
+++ b/.stylelintignore
@@ -4,7 +4,7 @@ docs/
 node_modules/
 external/bcmaps/
 external/builder/fixtures/
-external/builder/fixtures_esprima/
+external/builder/fixtures_babel/
 external/quickjs/
 test/tmp/
 test/pdfs/
diff --git a/external/builder/fixtures_esprima/blocks-expected.js b/external/builder/fixtures_babel/blocks-expected.js
similarity index 100%
rename from external/builder/fixtures_esprima/blocks-expected.js
rename to external/builder/fixtures_babel/blocks-expected.js
diff --git a/external/builder/fixtures_esprima/blocks.js b/external/builder/fixtures_babel/blocks.js
similarity index 100%
rename from external/builder/fixtures_esprima/blocks.js
rename to external/builder/fixtures_babel/blocks.js
diff --git a/external/builder/fixtures_esprima/comments-expected.js b/external/builder/fixtures_babel/comments-expected.js
similarity index 100%
rename from external/builder/fixtures_esprima/comments-expected.js
rename to external/builder/fixtures_babel/comments-expected.js
diff --git a/external/builder/fixtures_esprima/comments.js b/external/builder/fixtures_babel/comments.js
similarity index 100%
rename from external/builder/fixtures_esprima/comments.js
rename to external/builder/fixtures_babel/comments.js
diff --git a/external/builder/fixtures_esprima/constants-expected.js b/external/builder/fixtures_babel/constants-expected.js
similarity index 100%
rename from external/builder/fixtures_esprima/constants-expected.js
rename to external/builder/fixtures_babel/constants-expected.js
diff --git a/external/builder/fixtures_esprima/constants.js b/external/builder/fixtures_babel/constants.js
similarity index 100%
rename from external/builder/fixtures_esprima/constants.js
rename to external/builder/fixtures_babel/constants.js
diff --git a/external/builder/fixtures_esprima/deadcode-expected.js b/external/builder/fixtures_babel/deadcode-expected.js
similarity index 100%
rename from external/builder/fixtures_esprima/deadcode-expected.js
rename to external/builder/fixtures_babel/deadcode-expected.js
diff --git a/external/builder/fixtures_esprima/deadcode.js b/external/builder/fixtures_babel/deadcode.js
similarity index 100%
rename from external/builder/fixtures_esprima/deadcode.js
rename to external/builder/fixtures_babel/deadcode.js
diff --git a/external/builder/fixtures_esprima/evals-expected.js b/external/builder/fixtures_babel/evals-expected.js
similarity index 100%
rename from external/builder/fixtures_esprima/evals-expected.js
rename to external/builder/fixtures_babel/evals-expected.js
diff --git a/external/builder/fixtures_esprima/evals.js b/external/builder/fixtures_babel/evals.js
similarity index 85%
rename from external/builder/fixtures_esprima/evals.js
rename to external/builder/fixtures_babel/evals.js
index db03ab047..94ec543b0 100644
--- a/external/builder/fixtures_esprima/evals.js
+++ b/external/builder/fixtures_babel/evals.js
@@ -5,7 +5,7 @@ var d = PDFJSDev.test('FALSE');
 var e = PDFJSDev.eval('TRUE');
 var f = PDFJSDev.eval('TEXT');
 var g = PDFJSDev.eval('OBJ');
-var h = PDFJSDev.json('$ROOT/external/builder/fixtures_esprima/evals.json');
+var h = PDFJSDev.json('$ROOT/external/builder/fixtures_babel/evals.json');
 var i = typeof PDFJSDev === 'undefined' ? PDFJSDev.eval('FALSE') : '0';
 var j = typeof PDFJSDev !== 'undefined' ? PDFJSDev.eval('OBJ.obj') : '0';
 var k = !PDFJSDev.test('TRUE');
diff --git a/external/builder/fixtures_esprima/evals.json b/external/builder/fixtures_babel/evals.json
similarity index 100%
rename from external/builder/fixtures_esprima/evals.json
rename to external/builder/fixtures_babel/evals.json
diff --git a/external/builder/fixtures_esprima/ifs-expected.js b/external/builder/fixtures_babel/ifs-expected.js
similarity index 100%
rename from external/builder/fixtures_esprima/ifs-expected.js
rename to external/builder/fixtures_babel/ifs-expected.js
diff --git a/external/builder/fixtures_esprima/ifs.js b/external/builder/fixtures_babel/ifs.js
similarity index 100%
rename from external/builder/fixtures_esprima/ifs.js
rename to external/builder/fixtures_babel/ifs.js
diff --git a/external/builder/fixtures_esprima/importalias-expected.js b/external/builder/fixtures_babel/importalias-expected.js
similarity index 100%
rename from external/builder/fixtures_esprima/importalias-expected.js
rename to external/builder/fixtures_babel/importalias-expected.js
diff --git a/external/builder/fixtures_esprima/importalias.js b/external/builder/fixtures_babel/importalias.js
similarity index 100%
rename from external/builder/fixtures_esprima/importalias.js
rename to external/builder/fixtures_babel/importalias.js
diff --git a/external/builder/test-fixtures_esprima.mjs b/external/builder/test-fixtures_babel.mjs
similarity index 93%
rename from external/builder/test-fixtures_esprima.mjs
rename to external/builder/test-fixtures_babel.mjs
index 5eccb66c0..e7afa4de4 100644
--- a/external/builder/test-fixtures_esprima.mjs
+++ b/external/builder/test-fixtures_babel.mjs
@@ -7,7 +7,7 @@ const __dirname = path.dirname(fileURLToPath(import.meta.url));
 
 let errors = 0;
 
-const baseDir = path.join(__dirname, "fixtures_esprima");
+const baseDir = path.join(__dirname, "fixtures_babel");
 const files = fs
   .readdirSync(baseDir)
   .filter(function (name) {
@@ -49,7 +49,7 @@ files.forEach(function (expectationFilename) {
     errors++;
 
     // Allow regenerating the expected output using
-    //   OVERWRITE=true node ./external/builder/test-fixtures_esprima.mjs
+    //   OVERWRITE=true node ./external/builder/test-fixtures_babel.mjs
     if (process.env.OVERWRITE) {
       fs.writeFileSync(expectationFilename, out + "\n");
     }
diff --git a/gulpfile.mjs b/gulpfile.mjs
index 4f3af9d64..4b624942d 100644
--- a/gulpfile.mjs
+++ b/gulpfile.mjs
@@ -2414,8 +2414,8 @@ gulp.task("externaltest", function (done) {
   });
 
   console.log();
-  console.log("### Running test-fixtures_esprima.js");
-  safeSpawnSync("node", ["external/builder/test-fixtures_esprima.mjs"], {
+  console.log("### Running test-fixtures_babel.js");
+  safeSpawnSync("node", ["external/builder/test-fixtures_babel.mjs"], {
     stdio: "inherit",
   });
   done();

From 46626ac64a7de87423c5b2879d6a3c998135d400 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nribaudo@igalia.com>
Date: Thu, 9 May 2024 15:11:59 +0200
Subject: [PATCH 2/2] Update the Babel plugin to remove empty class
 constructors

This only happens when it's safe to do so. The exceptions are:
- when the class extends another subclass: removing the constructor would remove the error about the missing super() call
- when there are default parameters, that could have side effects
- when there are destructured prameters, that could have side effects
---
 .../babel-plugin-pdfjs-preprocessor.mjs       | 20 ++++++++++
 .../fixtures_babel/constructors-expected.js   | 23 ++++++++++++
 .../builder/fixtures_babel/constructors.js    | 37 +++++++++++++++++++
 3 files changed, 80 insertions(+)
 create mode 100644 external/builder/fixtures_babel/constructors-expected.js
 create mode 100644 external/builder/fixtures_babel/constructors.js

diff --git a/external/builder/babel-plugin-pdfjs-preprocessor.mjs b/external/builder/babel-plugin-pdfjs-preprocessor.mjs
index 945d22c47..8c5254e73 100644
--- a/external/builder/babel-plugin-pdfjs-preprocessor.mjs
+++ b/external/builder/babel-plugin-pdfjs-preprocessor.mjs
@@ -234,6 +234,26 @@ function babelPluginPDFJSPreprocessor(babel, ctx) {
           }
         },
       },
+      ClassMethod: {
+        exit(path) {
+          const {
+            node,
+            parentPath: { parent: classNode },
+          } = path;
+          if (
+            // Remove empty constructors. We only do this for
+            // base classes, as the default constructor of derived
+            // classes is not empty (and an empty constructor
+            // must throw at runtime when constructed).
+            node.kind === "constructor" &&
+            node.body.body.length === 0 &&
+            node.params.every(p => p.type === "Identifier") &&
+            !classNode.superClass
+          ) {
+            path.remove();
+          }
+        },
+      },
     },
   };
 }
diff --git a/external/builder/fixtures_babel/constructors-expected.js b/external/builder/fixtures_babel/constructors-expected.js
new file mode 100644
index 000000000..841e53851
--- /dev/null
+++ b/external/builder/fixtures_babel/constructors-expected.js
@@ -0,0 +1,23 @@
+class A {
+  constructor() {
+    console.log("Hi!");
+  }
+}
+class B {
+  constructor(x = console.log("Hi!")) {}
+}
+class C {
+  constructor({
+    x
+  }) {}
+}
+class D {}
+class E extends A {
+  constructor() {}
+}
+class F {
+  constructor() {
+    var a = 0;
+  }
+}
+class G {}
diff --git a/external/builder/fixtures_babel/constructors.js b/external/builder/fixtures_babel/constructors.js
new file mode 100644
index 000000000..8d7f41216
--- /dev/null
+++ b/external/builder/fixtures_babel/constructors.js
@@ -0,0 +1,37 @@
+class A {
+  constructor() {
+    console.log("Hi!");
+  }
+}
+
+class B {
+  constructor(x = console.log("Hi!")) {}
+}
+
+class C {
+  constructor({ x }) {}
+}
+
+class D {
+  constructor(x, y, z) {}
+}
+
+class E extends A {
+  constructor() {}
+}
+
+class F {
+  constructor() {
+    if (PDFJSDev.test('TRUE')) {
+      var a = 0;
+    }
+  }
+}
+
+class G {
+  constructor() {
+    if (PDFJSDev.test('FALSE')) {
+      var a = 0;
+    }
+  }
+}