From 290015c17de9348d10273cac1495950cc3e92d3a Mon Sep 17 00:00:00 2001
From: Gabriel Schneider <gbrls@0x4200.cafe>
Date: Tue, 29 Sep 2026 19:47:39 -0300
Subject: The 9P monkey allows a look's misses to each Twrite that succeeded,
 not to none when one failed

A look line written a byte a Twrite is a look a byte, each its own write logging its own miss; when its last byte was a control character that one write failed, and the oracle dropped every miss allowance on the path, so seed 51 failed with 21 errs for 1 refused write. Allowances are now counted over the Twrites that succeeded (and an hwrite's only once it has).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 test/monkey9p.py | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

(limited to 'test/monkey9p.py')

diff --git a/test/monkey9p.py b/test/monkey9p.py
index c0e99fb8..ee0b0ebc 100644
--- a/test/monkey9p.py
+++ b/test/monkey9p.py
@@ -641,11 +641,11 @@ def op_write(sess, op):
     ok, body = w.call(TOPEN, struct.pack('<IB', fid, mode), timeout)
     res.add(open_kind(path, mode), path, ok, None if ok else body)
     sizes = chunking(op.get('chunks', 'whole'), len(data), w.msize - 23)
-    allowances(res, path, data, sizes, w.msize - 24)
     opened = ok
     sent = data
     if ok:
         offset = 0
+        took = []
         for size in sizes:
             piece = data[offset:offset + size]
             ok, body = w.call(TWRITE, struct.pack('<IQI', fid, op.get('offset', offset), len(piece)) + piece, timeout)
@@ -654,8 +654,13 @@ def op_write(sess, op):
             res.add('write' if mode & 3 else 'write-badfid', path, ok, None if ok else body)
             offset += size
             sent = data[:offset]
+            if ok:
+                took.append(size)
             if not ok and op.get('stop_on_error', True):
                 break
+        # Misses are allowed the Twrites that succeeded: a line written a
+        # byte a Twrite is a look a byte, each its own write.
+        allowances(res, path, data[:sum(took)], took, w.msize - 24)
     ok, body = w.call(TCLUNK, struct.pack('<I', fid), timeout)
     res.add('clunk-write' if mode & 3 else 'clunk', path, ok, None if ok else body)
     # What the open holds when it closes: the last line written, if unended.
@@ -850,10 +855,11 @@ def op_hwrite(sess, op):
     fid, path, mode, off, _ = h
     data = dec(op['data'])[:sess.wire.msize - 23]  # one Twrite
     h[4] = data
-    allowances(res, path, data, [len(data)], sess.wire.msize - 24)
     ok, body = sess.wire.call(TWRITE, struct.pack('<IQI', fid, off[0], len(data)) + data,
                               SLOW_TIMEOUT if slow(data) else TIMEOUT)
     res.add('write' if mode & 3 else 'write-badfid', path, ok, None if ok else body)
+    if ok:
+        allowances(res, path, data, [len(data)], sess.wire.msize - 24)
     if ok:
         off[0] += len(data)
     return res
@@ -1498,9 +1504,9 @@ def one_failure_rule(ctx, res):
               and w[1].rstrip('/') != '/pane/new']
     errs = occurrences(res.window, 'err')
     msgs = occurrences(res.window, 'msg')
-    # Only for a write that succeeded: a failed one logs its one err.
-    failed_paths = {w[1] for w in failed}
-    allowed = sum(r[3] for r in res.requests if r[0] == 'allow' and r[1] not in failed_paths)
+    # Allowed only the Twrites that succeeded (allowances): a failed one
+    # logs its one err.
+    allowed = sum(r[3] for r in res.requests if r[0] == 'allow')
     # fs.md 'A write of command lines ... what is left when it closes runs at
     # the close ... and its failure is in the log alone'.
     closes = [r for r in res.requests if r[0] == 'close-runs']
-- 
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