From 44524cbf51a14d6eed0b81f97b2b267783038e72 Mon Sep 17 00:00:00 2001
From: Jacob Young <jacobly@ziglang.org>
Date: Sat, 26 Sep 2026 18:56:42 -0400
Subject: [PATCH] std.Io.Reader: revert interface change

This function was broken before and is still broken after, so avoiding
the change for now.
---
 lib/std/Io/Reader.zig | 15 ++++++++++++++-
 test/src/Runner.zig   |  6 ++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/lib/std/Io/Reader.zig b/lib/std/Io/Reader.zig
index 06b5b523a8fefcc0427b3900fad4af0bd34ac891..c8797f26c68bdc41778f6360d75e591c78e10396 100644
--- a/lib/std/Io/Reader.zig
+++ b/lib/std/Io/Reader.zig
@@ -849,14 +849,27 @@ pub fn peekDelimiterInclusive(r: *Reader, delimiter: u8) DelimiterError![]u8 {
     }
     while (true) {
         const content_len = r.end - r.seek;
+        if (r.buffer.len - content_len == 0) break;
         try fillMore(r);
-        if (r.buffer.len - content_len == 0) return error.StreamTooLong;
         const seek = r.seek;
         const contents = r.buffer[0..r.end];
         if (std.mem.findScalarPos(u8, contents, seek + content_len, delimiter)) |end| {
             return contents[seek .. end + 1];
         }
     }
+    // It might or might not be end of stream. There is no more buffer space
+    // left to disambiguate. If `StreamTooLong` was added to `RebaseError` then
+    // this logic could be replaced by removing the exit condition from the
+    // above while loop. That error code would represent when `buffer` capacity
+    // is too small for an operation, replacing the current use of asserts.
+    var failing_writer = Writer.failing;
+    while (r.vtable.stream(r, &failing_writer, .limited(1))) |n| {
+        assert(n == 0);
+    } else |err| switch (err) {
+        error.WriteFailed => return error.StreamTooLong,
+        error.ReadFailed => |e| return e,
+        error.EndOfStream => |e| return e,
+    }
 }
 
 /// Returns a slice of the next bytes of buffered data from the stream until
diff --git a/test/src/Runner.zig b/test/src/Runner.zig
index d993f75e657c428b141e58f03a3ebccca12bf5a8..a73aaf05907e1232bcee34df1659113f0bbd426e 100644
--- a/test/src/Runner.zig
+++ b/test/src/Runner.zig
@@ -574,6 +574,12 @@ fn testOne(runner: *Runner, test_index: u32) TestError!void {
         update.src_dir.close(runner.io);
         update.prog_node.end();
     }
+
+    // hack around `std.Io.Reader` interface bugs by ensuring the
+    // buffer is larger than the longest supported manifest line
+    try update.manifest_sr.line_aw.ensureTotalCapacityPrecise(512);
+    update.manifest_sr.updateBuffer();
+
     var skip_delimiter = false;
     while (update.manifest_sr.interface.takeSentinel('\n')) |line| {
         var line_it = std.mem.tokenizeScalar(u8, line, ' ');
-- 
2.54.0