Merge pull request #2509 from navidemad/fix/network-pollfds-clobbers-cdp-sockets

Fix CDP server stall/SIGTERM hang in optimized builds (Network drops CDP sockets from poll set)

Author: karlseguin

src/network/Network.zig

@@ -722,8 +722,15 @@ pub fn run(self: *Network) void {
                 break :blk min_timeout;
             }
 
+            // curl_multi_timeout reports -1 when curl has no timeout
+            // preference (idle) and 0 when it wants to be serviced
+            // immediately. Treat both as "no curl-imposed deadline" and
+            // fall back to min_timeout — otherwise @min(min_timeout, -1)
+            // would be -1, i.e. poll() blocks forever, starving onTick
+            // (telemetry's periodic flush) and removing the safety net
+            // that bounds any missed wakeup to min_timeout.
             const curl_timeout = self.getCurlTimeout();
-            if (curl_timeout == 0) {
+            if (curl_timeout <= 0) {
                 break :blk min_timeout;
             }
 
@@ -860,7 +867,16 @@ fn acceptConnections(self: *Network) void {
 }
 
 fn preparePollFds(self: *Network, multi: *libcurl.CurlM) void {
-    const curl_fds = self.pollfds[PSEUDO_POLLFDS..];
+    // Only the curl slice — NOT through to the end of pollfds. The CDP
+    // socket fds live in [cdp_start..] and are owned by
+    // prepareCdpPollFds, which only rebuilds them when cdp_dirty is set
+    // (a steady-state optimization). Slicing to the end here would
+    // @memset those fds to -1 every iteration once a multi exists (which
+    // happens as soon as telemetry sends its first request), silently
+    // dropping every live CDP socket from the poll set — Network then
+    // never reads another CDP message (#2508) nor observes peer
+    // EOF/shutdown (#2507).
+    const curl_fds = self.pollfds[PSEUDO_POLLFDS..self.cdp_start];
     @memset(curl_fds, .{ .fd = -1, .events = 0, .revents = 0 });
 
     var fd_count: c_uint = 0;
@@ -1053,3 +1069,40 @@ fn loadCerts(allocator: Allocator) !libcurl.CurlBlob {
         .flags = 0,
     };
 }
+
+const testing = @import("../testing.zig");
+
+test "Network: preparePollFds leaves the CDP fd region untouched" {
+    // Regression for #2507 / #2508. Once a multi exists (telemetry creates
+    // one in optimized builds), preparePollFds runs every loop iteration.
+    // It rebuilds only the curl slice [PSEUDO_POLLFDS..cdp_start]; the CDP
+    // region [cdp_start..] is owned by prepareCdpPollFds, which keeps its
+    // entries across iterations and only rebuilds when cdp_dirty is set.
+    // A slice that ran to the end of pollfds @memset those CDP sockets to
+    // -1, silently dropping every live CDP connection from the poll set —
+    // so Network stopped reading CDP messages (#2508) and never observed
+    // peer EOF/shutdown (#2507). curl global is initialized by the test
+    // harness (App.init -> Network.init).
+    const multi = libcurl.curl_multi_init() orelse return error.FailedToInitMulti;
+    defer libcurl.curl_multi_cleanup(multi) catch {};
+
+    const curl_slots = 4;
+    const cdp_slots = 3;
+    var pollfds: [PSEUDO_POLLFDS + curl_slots + cdp_slots]posix.pollfd = undefined;
+    @memset(&pollfds, .{ .fd = -1, .events = 0, .revents = 0 });
+
+    // preparePollFds only reads self.pollfds and self.cdp_start.
+    var nw: Network = undefined;
+    nw.pollfds = &pollfds;
+    nw.cdp_start = PSEUDO_POLLFDS + curl_slots;
+
+    // Two live CDP sockets parked in the CDP region, mimicking the steady
+    // state between cdp_dirty rebuilds.
+    pollfds[nw.cdp_start] = .{ .fd = 4242, .events = posix.POLL.IN, .revents = 0 };
+    pollfds[nw.cdp_start + 1] = .{ .fd = 4243, .events = posix.POLL.IN, .revents = 0 };
+
+    nw.preparePollFds(multi);
+
+    try testing.expectEqual(@as(posix.fd_t, 4242), pollfds[nw.cdp_start].fd);
+    try testing.expectEqual(@as(posix.fd_t, 4243), pollfds[nw.cdp_start + 1].fd);
+}