Use protopiler for protocol buffers

Co-authored-by: Jamie Kyle <jamie@signal.org>

codemods/protopiler-migration/01-remove-finish.js

@@ -0,0 +1,35 @@
+// Copyright 2026 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+export default function transform() {
+  return {
+    visitor: {
+      CallExpression(path) {
+        const { node } = path;
+        if (node.arguments.length !== 0) {
+          return;
+        }
+        if (node.callee.type !== 'MemberExpression') {
+          return;
+        }
+        const { object, property } = node.callee;
+        if (object.type !== 'CallExpression') {
+          return;
+        }
+
+        if (property.type !== 'Identifier' || property.name !== 'finish') {
+          return;
+        }
+
+        if (
+          object.callee.type !== 'MemberExpression' ||
+          object.callee.property.type !== 'Identifier' ||
+          object.callee.property.name !== 'encode'
+        ) {
+          return;
+        }
+
+        path.replaceWith(object);
+      },
+    },
+  };
+}

codemods/protopiler-migration/02-remove-i.js

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+// Copyright 2026 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+export default function transform(babel) {
+  const { types: t } = babel;
+
+  return {
+    visitor: {
+      TSQualifiedName(path) {
+        const { node } = path;
+        if (
+          node.right.type !== 'Identifier' ||
+          !/^I[A-Z][a-z]/.test(node.right.name)
+        ) {
+          return;
+        }
+
+        // Don't touch fuse.js
+        if (node.left.type === 'Identifier' && node.left.name === 'Fuse') {
+          return;
+        }
+
+        path.replaceWith(
+          t.TSQualifiedName(
+            t.TSQualifiedName(
+              node.left,
+              t.Identifier(node.right.name.slice(1))
+            ),
+            t.Identifier('Params')
+          )
+        );
+      },
+    },
+  };
+}

codemods/protopiler-migration/03-to-number.js

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+// Copyright 2026 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import { relative, dirname, join } from 'node:path';
+
+const importPath = join(__dirname, '..', 'ts', 'util', 'toNumber.std.js');
+
+export default function transform(babel) {
+  const { types: t } = babel;
+
+  let program;
+  function Program({ node }) {
+    program = node;
+  }
+
+  function addImport(filename) {
+    if (program === undefined) {
+      return;
+    }
+
+    let index = program.body.findLastIndex(
+      stmt => stmt.type === 'ImportDeclaration'
+    );
+    if (index === -1) {
+      index = 0;
+    } else {
+      index += 1;
+    }
+    let relativePath = relative(dirname(filename), importPath);
+    if (!relativePath.startsWith('.')) {
+      relativePath = `./${relativePath}`;
+    }
+    program.body.splice(
+      index,
+      0,
+      t.ImportDeclaration(
+        [t.ImportSpecifier(t.Identifier('toNumber'), t.Identifier('toNumber'))],
+        t.StringLiteral(relativePath)
+      )
+    );
+    program = undefined;
+  }
+
+  function CallExpression(path, { filename }) {
+    const { callee, arguments: args } = path.node;
+    if (args.length !== 0) {
+      return;
+    }
+    if (
+      callee.type !== 'MemberExpression' &&
+      callee.type !== 'OptionalMemberExpression'
+    ) {
+      return;
+    }
+    if (
+      callee.property.type !== 'Identifier' ||
+      callee.property.name !== 'toNumber'
+    ) {
+      return;
+    }
+
+    const replacement = t.CallExpression(t.Identifier('toNumber'), [
+      callee.object,
+    ]);
+    path.replaceWith(replacement);
+    addImport(filename);
+  }
+
+  return {
+    visitor: {
+      Program,
+      CallExpression,
+      OptionalCallExpression: CallExpression,
+    },
+  };
+}

codemods/protopiler-migration/04-long-from-number.js

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+// Copyright 2026 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+export default function transform(babel) {
+  const { types: t } = babel;
+
+  return {
+    visitor: {
+      CallExpression(path) {
+        const { node } = path;
+        if (node.arguments.length !== 1) {
+          return;
+        }
+        if (node.callee.type !== 'MemberExpression') {
+          return;
+        }
+        const { object, property } = node.callee;
+        if (object.type !== 'Identifier' || object.name !== 'Long') {
+          return;
+        }
+        if (property.type !== 'Identifier') {
+          return;
+        }
+
+        if (property.name === 'isLong') {
+          path.replaceWith(
+            t.BinaryExpression(
+              '===',
+              t.UnaryExpression('typeof', node.arguments[0]),
+              t.StringLiteral('bigint')
+            )
+          );
+          return;
+        }
+
+        if (
+          property.name !== 'fromNumber' &&
+          property.name !== 'fromString' &&
+          property.name !== 'fromValue'
+        ) {
+          return;
+        }
+
+        if (node.arguments[0].type === 'NumericLiteral') {
+          path.replaceWith(t.BigIntLiteral(node.arguments[0].value.toString()));
+          return;
+        }
+        path.replaceWith(
+          t.CallExpression(t.Identifier('BigInt'), [node.arguments[0]])
+        );
+      },
+    },
+  };
+}