Add BUN_BE_BUN environment variable flag (#20251)

src/cli.zig

@@ -1815,29 +1815,31 @@ pub const Command = struct {
         }
 
         // bun build --compile entry point
-        if (try bun.StandaloneModuleGraph.fromExecutable(bun.default_allocator)) |graph| {
-            context_data = .{
-                .args = std.mem.zeroes(Api.TransformOptions),
-                .log = log,
-                .start_time = start_time,
-                .allocator = bun.default_allocator,
-            };
-            global_cli_ctx = &context_data;
-            var ctx = global_cli_ctx;
+        if (!bun.getRuntimeFeatureFlag(.BUN_BE_BUN)) {
+            if (try bun.StandaloneModuleGraph.fromExecutable(bun.default_allocator)) |graph| {
+                context_data = .{
+                    .args = std.mem.zeroes(Api.TransformOptions),
+                    .log = log,
+                    .start_time = start_time,
+                    .allocator = bun.default_allocator,
+                };
+                global_cli_ctx = &context_data;
+                var ctx = global_cli_ctx;
 
-            ctx.args.target = Api.Target.bun;
-            if (bun.argv.len > 1) {
-                ctx.passthrough = bun.argv[1..];
-            } else {
-                ctx.passthrough = &[_]string{};
+                ctx.args.target = Api.Target.bun;
+                if (bun.argv.len > 1) {
+                    ctx.passthrough = bun.argv[1..];
+                } else {
+                    ctx.passthrough = &[_]string{};
+                }
+
+                try @import("./bun_js.zig").Run.bootStandalone(
+                    ctx,
+                    graph.entryPoint().name,
+                    graph,
+                );
+                return;
             }
-
-            try @import("./bun_js.zig").Run.bootStandalone(
-                ctx,
-                graph.entryPoint().name,
-                graph,
-            );
-            return;
         }
 
         debug("argv: [{s}]", .{bun.fmt.fmtSlice(bun.argv, ", ")});

src/feature_flags.zig

@@ -5,6 +5,7 @@ const bun = @import("bun");
 /// The field names correspond exactly to the expected environment variable names.
 pub const RuntimeFeatureFlag = enum {
     BUN_ASSUME_PERFECT_INCREMENTAL,
+    BUN_BE_BUN,
     BUN_DEBUG_NO_DUMP,
     BUN_DESTRUCT_VM_ON_EXIT,
     BUN_DISABLE_SLOW_LIFECYCLE_SCRIPT_LOGGING,

test/bundler/bundler_compile.test.ts

@@ -607,4 +607,23 @@ error: Hello World`,
       },
     },
   });
+  itBundled("compile/BunBeBunEnvVar", {
+    compile: true,
+    files: {
+      "/entry.ts": /* js */ `
+        console.log("This is compiled code");
+      `,
+    },
+    run: [
+      {
+        stdout: "This is compiled code",
+      },
+      {
+        env: { BUN_BE_BUN: "1" },
+        validate({ stdout }) {
+          expect(stdout).not.toContain("This is compiled code");
+        },
+      },
+    ],
+  });
 });