[codex] Improve Bun.file HTTP URL error

src/runtime/webcore/Blob.rs

@@ -5541,12 +5541,18 @@ pub fn construct_bun_file(
     };
 
     if let PathOrFileDescriptor::Path(ref p) = path {
-        if p.slice().starts_with(b"s3://") {
+        let path_slice = p.slice();
+        if path_slice.starts_with(b"s3://") {
             // PORT NOTE (layering): `webcore::node_types::PathLike` re-exports
             // `crate::node::types::PathLike`, so no conversion is needed —
             // clone the path (Zig consumed it; the Rust `path` drops at scope exit).
             return S3File::construct_internal_js(global_object, p.clone(), options);
         }
+        if is_http_url_path(path_slice) {
+            return Err(global_object.throw_invalid_arguments(format_args!(
+                "Bun.file() does not support HTTP URLs. Use fetch() instead."
+            )));
+        }
     }
     // PORT NOTE: Zig `defer path.deinitAndUnprotect()` — sync path took no
     // `protect()`, so `Drop for PathOrFileDescriptor` suffices.
@@ -5593,6 +5599,14 @@ pub fn construct_bun_file(
     Ok(unsafe { BlobExt::to_js(&*ptr, global_object) })
 }
 
+fn is_http_url_path(path: &[u8]) -> bool {
+    path.get(.."http://".len())
+        .is_some_and(|prefix| prefix.eq_ignore_ascii_case(b"http://"))
+        || path
+            .get(.."https://".len())
+            .is_some_and(|prefix| prefix.eq_ignore_ascii_case(b"https://"))
+}
+
 // `find_or_create_file_from_path`: canonical impl lives later in this file
 // (runtime `check_s3: bool` form). Const-generic duplicate removed here.
 

src/runtime/webcore/Blob.zig

@@ -2068,9 +2068,13 @@ pub fn constructBunFile(
     const options = if (arguments.len >= 2) arguments[1] else null;
 
     if (path == .path) {
-        if (strings.hasPrefixComptime(path.path.slice(), "s3://")) {
+        const path_slice = path.path.slice();
+        if (strings.hasPrefixComptime(path_slice, "s3://")) {
             return try S3File.constructInternalJS(globalObject, path.path, options);
         }
+        if (isHTTPURLPath(path_slice)) {
+            return globalObject.throwInvalidArguments("Bun.file() does not support HTTP URLs. Use fetch() instead.", .{});
+        }
     }
     defer path.deinitAndUnprotect();
 
@@ -2109,6 +2113,11 @@ pub fn constructBunFile(
     return ptr.toJS(globalObject);
 }
 
+fn isHTTPURLPath(path: []const u8) bool {
+    return (path.len >= "http://".len and strings.eqlCaseInsensitiveASCII(path[0.."http://".len], "http://", true)) or
+        (path.len >= "https://".len and strings.eqlCaseInsensitiveASCII(path[0.."https://".len], "https://", true));
+}
+
 pub fn findOrCreateFileFromPath(path_or_fd: *jsc.Node.PathOrFileDescriptor, globalThis: *JSGlobalObject, comptime check_s3: bool) Blob {
     var vm = globalThis.bunVM();
     const allocator = bun.default_allocator;

test/js/bun/util/bun-file.test.ts

@@ -115,6 +115,13 @@ test("Bun.file().arrayBuffer() errors include async stack frames", async () => {
   expect(caught.stack).toContain("at async caller");
 });
 
+test("Bun.file() rejects remote URL strings with a helpful error", () => {
+  const message = "Bun.file() does not support HTTP URLs. Use fetch() instead.";
+
+  expect(() => Bun.file("https://example.com/image.png")).toThrow(message);
+  expect(() => Bun.file("http://example.com/image.png")).toThrow(message);
+});
+
 test("Bun.file().json() with UTF-8 BOM does not free an interior pointer", async () => {
   // When a file starts with EF BB BF, the BOM is stripped before parsing and
   // the temporary read buffer is freed. Previously the *post-strip* slice was