Commit 0bbf0461d9800ce5eba28cd32ef10492b2f80639 | zig

author	Luna Schwalbe <dev@luna.gl> 2025-12-07 04:28:01+01:00
committer	Andrew Kelley <andrew@ziglang.org> 2026-04-11 11:04:24-07:00
log	0bbf0461d9800ce5eba28cd32ef10492b2f80639
tree	228500b88381759742764348878cd1255f28d8d4
parent	29225ae11b93404f2d823ae45bfe68ce882706d1

std.http: reliably update reader state

Content length based reading would only set the reader state to `ready`
once it returned EOF, but wrapping readers (such as decompressors)
may stop reading from the underlying source without receiving EOF.
In such cases the http reader state would stay set to
`body_remaining_content_length`, even though the entire body had been
read.

Fixes #30060

Co-authored-by: Andrew Kelley <andre@ziglang.org>

2 files changed, 33 insertions(+), 9 deletions(-)

lib
- std
  - http.zig
  - http
    test.zig

lib/std/http.zig+11-9

 @@ -443,7 +443,7 @@ pub const Reader = struct {
             },
             .none => {
                 if (content_length) |len| {
-                    reader.state = .{ .body_remaining_content_length = len };
+                    reader.state = if (len == 0) .ready else .{ .body_remaining_content_length = len };
                     reader.interface = .{
                         .buffer = transfer_buffer,
                         .seek = 0,
 @@ -509,27 +509,29 @@ pub const Reader = struct {
         limit: std.Io.Limit,
     ) std.Io.Reader.StreamError!usize {
         const reader: *Reader = @alignCast(@fieldParentPtr("interface", io_r));
+        if (reader.state == .ready) return error.EndOfStream;
         const remaining_content_length = &reader.state.body_remaining_content_length;
         const remaining = remaining_content_length.*;
-        if (remaining == 0) {
+        const n = try reader.in.stream(w, limit.min(.limited64(remaining)));
+        if (n == remaining) {
             reader.state = .ready;
-            return error.EndOfStream;
+        } else {
+            remaining_content_length.* = remaining - n;
         }
-        const n = try reader.in.stream(w, limit.min(.limited64(remaining)));
-        remaining_content_length.* = remaining - n;
         return n;
     }
     fn contentLengthDiscard(io_r: *std.Io.Reader, limit: std.Io.Limit) std.Io.Reader.Error!usize {
         const reader: *Reader = @alignCast(@fieldParentPtr("interface", io_r));
+        if (reader.state == .ready) return error.EndOfStream;
         const remaining_content_length = &reader.state.body_remaining_content_length;
         const remaining = remaining_content_length.*;
-        if (remaining == 0) {
+        const n = try reader.in.discard(limit.min(.limited64(remaining)));
+        if (n == remaining) {
             reader.state = .ready;
-            return error.EndOfStream;
+        } else {
+            remaining_content_length.* = remaining - n;
         }
-        const n = try reader.in.discard(limit.min(.limited64(remaining)));
-        remaining_content_length.* = remaining - n;
         return n;
     }

lib/std/http/test.zig+22

...	@@ -11,6 +11,28 @@ const expectEqual = std.testing.expectEqual;	...	@@ -11,6 +11,28 @@ const expectEqual = std.testing.expectEqual;
11	const expectEqualStrings = std.testing.expectEqualStrings;	11	const expectEqualStrings = std.testing.expectEqualStrings;
12	const expectError = std.testing.expectError;	12	const expectError = std.testing.expectError;
13		13
		14	test "content length reader state update" {
		15	var in = Io.Reader.fixed("HTTP/1.1 200 OK\r\nContent-Length: 6\r\n\r\nHello!\r\nHTTP/1.1 200 OK\r\n\r\n");
		16	var reader: http.Reader = .{
		17	.in = &in,
		18	.interface = undefined,
		19	.state = .ready,
		20	.max_head_len = 1024,
		21	};
		22
		23	_ = try reader.receiveHead();
		24	var body: [6]u8 = undefined;
		25	_ = try reader.bodyReader(&.{}, .none, body.len).readSliceAll(&body);
		26	try expectEqual(.ready, reader.state);
		27	_ = try reader.receiveHead();
		28
		29	in.seek = 0;
		30	_ = try reader.receiveHead();
		31	try reader.bodyReader(&.{}, .none, body.len).discardAll(body.len);
		32	try expectEqual(.ready, reader.state);
		33	_ = try reader.receiveHead();
		34	}
		35
14	test "trailers" {	36	test "trailers" {
15	if (builtin.cpu.arch.isPowerPC64() and builtin.mode != .Debug) return error.SkipZigTest; // https://github.com/llvm/llvm-project/issues/171879	37	if (builtin.cpu.arch.isPowerPC64() and builtin.mode != .Debug) return error.SkipZigTest; // https://github.com/llvm/llvm-project/issues/171879
16	if (builtin.os.tag == .openbsd) return error.SkipZigTest; // https://codeberg.org/ziglang/zig/issues/30806	38	if (builtin.os.tag == .openbsd) return error.SkipZigTest; // https://codeberg.org/ziglang/zig/issues/30806