feat: resolve __SST_DIRNAME and __SST_FILENAME at built time

packages/sst/package.json

@@ -60,6 +60,7 @@
     "@babel/core": "^7.0.0-0",
     "@babel/generator": "^7.20.5",
     "@babel/plugin-syntax-typescript": "^7.21.4",
+    "@babel/types": "^7.27.0",
     "@smithy/signature-v4": "^2.0.16",
     "@trpc/server": "9.16.0",
     "adm-zip": "0.5.14",

packages/sst/src/constructs/App.ts

@@ -280,6 +280,11 @@ export class App extends CDKApp {
         `  }`,
         `}`,
         ``,
+        `declare global {`,
+        `  const __SST_DIRNAME: string;`,
+        `  const __SST_FILENAME: string;`,
+        `}`,
+        ``,
         ``,
       ].join("\n")
     );
@@ -375,9 +380,9 @@ export class App extends CDKApp {
                 new PolicyStatement({
                   effect: Effect.ALLOW,
                   actions: [
-                    "s3:GetObject", 
-                    "s3:GetObjectTagging", 
-                    "s3:PutObject", 
+                    "s3:GetObject",
+                    "s3:GetObjectTagging",
+                    "s3:PutObject",
                     "s3:PutObjectTagging"
                   ],
                   resources: [

packages/sst/src/stacks/build.ts

@@ -5,6 +5,7 @@ import { dynamicImport } from "../util/module.js";
 import { findAbove } from "../util/fs.js";
 import { VisibleError } from "../error.js";
 import babel from "@babel/core";
+import { stringLiteral } from "@babel/types";
 const _ = await import("@babel/generator");
 const generate = _.default?.default ?? _.default;
 // @ts-expect-error
@@ -86,6 +87,42 @@ export async function load(input: string, shallow?: boolean) {
             });
           },
         },
+        {
+          name: "pathReplacer",
+          setup(build) {
+            build.onLoad({ filter: /.*/ }, async (args) => {
+              let contents = await fs
+                  .readFile(args.path)
+                  .then((x) => x.toString());
+              const ast = babel.parse(contents, {
+                sourceType: "module",
+                babelrc: false,
+                configFile: false,
+                plugins: [ts],
+              });
+              if (ast === null) {
+                console.error(`Error parsing ${args.path} as AST`);
+                return
+              }
+              babel.traverse(ast, {
+                Identifier(astPath) {
+                  if (astPath.node.name === "__SST_FILENAME") {
+                    astPath.replaceWith(stringLiteral(args.path));
+                  }
+                  if (astPath.node.name === "__SST_DIRNAME") {
+                    astPath.replaceWith(
+                        stringLiteral(path.parse(args.path).dir)
+                    );
+                  }
+                },
+              });
+              return {
+                contents: generate(ast!).code,
+                loader: "ts",
+              };
+            });
+          },
+        },
       ],
       absWorkingDir: root,
       outfile,