a73x

574464a6

docs: leg 1 is the agent probe's own sequence, not leg 2

a73x   2026-09-03 19:13

Commit message
docs: leg 1 is the agent probe's own sequence, not leg 2

mux_main.agentReachable sends once on a socket it just connected and then
closes it, so the state it meets is a socket that was never written to.
The comment named the second leg as the caller's; say which leg is whose
and why the other is asked anyway.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SakwJEwD9dXBoRP5kWbemW

src/os/client_os.zig
Old New
@@ -151,10 +151,13 @@ test "client_os.sendNoSig: a closed peer is an error, not a signal" {
151 }; 151 };
152 std.posix.sigaction(std.posix.SIG.PIPE, &dfl, null); 152 std.posix.sigaction(std.posix.SIG.PIPE, &dfl, null);
153 // Two legs, because "the peer is gone" is two different states to 153 // Two legs, because "the peer is gone" is two different states to
154 // the kernel and only the second is the one the probe meets. A 154 // the kernel, and the first is the one the probe meets:
155 // socket that was NEVER written to and then lost its peer is the 155 // `mux_main.agentReachable` sends once on a socket it just connected
156 // easy case; a socket that carried bytes and then lost its peer is 156 // and then closes it, so a daemon that hung up in between leaves a
157 // the probe's own sequence, and on Darwin the two differ — the flag 157 // socket that was never written to. The second leg — a socket that
158 // carried bytes and then lost its peer — is asked because this
159 // operation is a contract and not one caller's helper, and on Darwin
160 // the two states differ where they do not on Linux: the flag
158 // that suppresses the signal is a socket option there, and a socket 161 // that suppresses the signal is a socket option there, and a socket
159 // the kernel has already shut down refuses to take one (see 162 // the kernel has already shut down refuses to take one (see
160 // `client_os_macos.sendNoSig`). A test that asked only the first 163 // `client_os_macos.sendNoSig`). A test that asked only the first