Fix 'Container is falsy' bug due to Babel upgrade (#2175)

.changeset/heavy-radios-doubt.md

@@ -0,0 +1,8 @@
+---
+"eslint-plugin-graphile-export": patch
+"graphile-export": patch
+"postgraphile": patch
+---
+
+Fix 'Container is falsy' error message the latest Babel patch release would
+cause.

package.json

@@ -28,15 +28,15 @@
     "prettier:check": "yarn prettier:all --list-different"
   },
   "devDependencies": {
-    "@babel/cli": "^7.22.10",
-    "@babel/core": "^7.22.11",
-    "@babel/eslint-parser": "^7.22.11",
+    "@babel/cli": "^7.25.6",
+    "@babel/core": "^7.25.2",
+    "@babel/eslint-parser": "^7.25.1",
     "@babel/plugin-syntax-object-rest-spread": "^7.8.3",
-    "@babel/plugin-transform-modules-commonjs": "^7.22.11",
-    "@babel/plugin-transform-runtime": "^7.22.10",
-    "@babel/preset-env": "^7.22.14",
-    "@babel/preset-react": "^7.22.5",
-    "@babel/preset-typescript": "^7.22.11",
+    "@babel/plugin-transform-modules-commonjs": "^7.24.8",
+    "@babel/plugin-transform-runtime": "^7.25.4",
+    "@babel/preset-env": "^7.25.4",
+    "@babel/preset-react": "^7.24.7",
+    "@babel/preset-typescript": "^7.24.7",
     "@knodes/typedoc-plugin-monorepo-readmes": "^0.23.1",
     "@knodes/typedoc-plugin-pages": "^0.23.4",
     "@localrepo/prettier2-for-jest": "npm:prettier@^2",
@@ -48,7 +48,7 @@
     "@typescript-eslint/eslint-plugin": "^6.5.0",
     "@typescript-eslint/parser": "^6.5.0",
     "@typescript-eslint/typescript-estree": "^6.5.0",
-    "babel-jest": "^29.6.4",
+    "babel-jest": "^29.7.0",
     "babel-plugin-transform-import-meta": "^2.2.1",
     "concurrently": "^8.2.1",
     "eslint": "^8.48.0",

utils/eslint-plugin-graphile-export/package.json

@@ -37,7 +37,7 @@
     "dist"
   ],
   "devDependencies": {
-    "@babel/types": "^7.22.11",
+    "@babel/types": "^7.25.6",
     "@types/eslint": "^8.44.2",
     "@types/estree": "^1.0.1",
     "@types/jest": "^29.5.4",

utils/graphile-export/package.json

@@ -40,11 +40,11 @@
   },
   "homepage": "https://graphile.org/",
   "dependencies": {
-    "@babel/generator": "^7.22.10",
-    "@babel/parser": "^7.22.14",
-    "@babel/template": "^7.22.5",
-    "@babel/traverse": "^7.23.2",
-    "@babel/types": "^7.22.11",
+    "@babel/generator": "^7.25.6",
+    "@babel/parser": "^7.25.6",
+    "@babel/template": "^7.25.0",
+    "@babel/traverse": "^7.25.6",
+    "@babel/types": "^7.25.6",
     "@types/node": "^20.5.7",
     "prettier": "^3.0.3",
     "tslib": "^2.6.2"
@@ -69,8 +69,8 @@
     "dist"
   ],
   "devDependencies": {
-    "@types/babel__generator": "^7.6.4",
-    "@types/babel__template": "^7.4.1",
+    "@types/babel__generator": "^7.6.8",
+    "@types/babel__template": "^7.4.4",
     "@types/jest": "^29.5.4",
     "@types/prettier": "^3.0.0",
     "jest": "^29.6.4",

utils/graphile-export/src/optimize/index.ts

@@ -170,47 +170,63 @@ export const optimize = (inAst: t.File, runs = 1): t.File => {
       },
     },
     Program: {
-      exit(path) {
-        // Replace all things that are only referenced once
-        for (const [bindingName, binding] of Object.entries(
-          path.scope.bindings,
-        )) {
-          if (
-            !t.isVariableDeclarator(binding.path.node) &&
-            !t.isFunctionDeclaration(binding.path.node)
-          ) {
-            continue;
+      exit(exitPath) {
+        // Make sure our scope information is up to date!
+        exitPath.scope.crawl();
+
+        // Replace all things that are only referenced once.
+        // This nested traversal approach inspired by https://github.com/babel/babel/issues/15544#issuecomment-1540542863
+        exitPath.traverse({
+          VariableDeclarator: visitSubpath,
+          FunctionDeclaration: visitSubpath,
+        });
+        function visitSubpath(
+          path:
+            | NodePath<t.VariableDeclarator>
+            | NodePath<t.FunctionDeclaration>,
+        ) {
+          if (!t.isIdentifier(path.node.id)) {
+            return;
+          }
+          const bindingName = path.node.id.name;
+          const scope = t.isFunctionDeclaration(path.node)
+            ? path.scope.parent
+            : path.scope;
+          // Only optimize at top level
+          if (scope !== exitPath.scope) {
+            return;
           }
-          if (!t.isIdentifier(binding.path.node.id)) {
-            continue;
+          const binding = scope.bindings[bindingName];
+          if (!binding) {
+            return;
           }
-          const expr = t.isFunctionDeclaration(binding.path.node)
+          const expr = t.isFunctionDeclaration(path.node)
             ? // Convert function to expression
               t.functionExpression(
-                binding.path.node.id,
-                binding.path.node.params,
-                binding.path.node.body,
-                binding.path.node.generator,
-                binding.path.node.async,
+                path.node.id,
+                path.node.params,
+                path.node.body,
+                path.node.generator,
+                path.node.async,
               )
-            : binding.path.node.init;
+            : path.node.init;
           if (!expr) {
-            continue;
+            return;
           }
 
           // Skip if it's an export
-          const statementPath = binding.path.getStatementParent();
+          const statementPath = path.getStatementParent();
           if (
             !statementPath ||
             t.isExportNamedDeclaration(statementPath.node) ||
             t.isExportDefaultDeclaration(statementPath.node)
           ) {
-            continue;
+            return;
           }
 
           // Only replace if it's only referenced once (we don't want duplicates)
           if (binding.referencePaths.length !== 1) {
-            continue;
+            return;
           }
           const targetPath = binding.referencePaths[0];
           const parent = targetPath.parent;
@@ -222,7 +238,7 @@ export const optimize = (inAst: t.File, runs = 1): t.File => {
             parent.callee === targetPath.node &&
             (!t.isArrowFunctionExpression(expr) || t.isBlock(expr.body))
           ) {
-            continue;
+            return;
           }
 
           // It's allowed if:
@@ -231,12 +247,14 @@ export const optimize = (inAst: t.File, runs = 1): t.File => {
           const targetFunctionParent = targetPath.getFunctionParent();
           const sourceFunctionParent = path.getFunctionParent();
           if (targetFunctionParent !== sourceFunctionParent) {
-            continue;
+            return;
           }
 
           targetPath.replaceWith(expr);
-          binding.path.remove();
-          binding.path.scope.removeBinding(bindingName);
+          // This stopping is important to avoid 'Container is falsy' errors.
+          targetPath.stop();
+          scope.removeBinding(bindingName);
+          path.remove();
         }
       },
     },