Every child starts with its signals at their defaults and none blocked

Shells, command panes, language servers, the link opener and the v9fs mount inherited the editor's signal mask (the tty's blocked SIGWINCH) and anything it ignored (a SIGHUP nohup ignored), since only handlers reset at exec. Each fork now resets every disposition and clears the mask before its exec (resetChildSignals); std's spawn for selection pipes runs with the mask cleared across it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/selection_pipe.zig b/src/selection_pipe.zig
index e1a42962..44cc1709 100644
--- a/src/selection_pipe.zig
+++ b/src/selection_pipe.zig
@@ -202,6 +202,14 @@ pub fn runOne(
     if (std.mem.indexOfScalar(u8, command, 0) != null or
         std.mem.indexOfScalar(u8, cwd, 0) != null) return fail.k(.spawn);
 
+    // std's spawn runs no code in the child: this thread's mask, which the
+    // child inherits, is cleared across the fork (only the tty's SIGWINCH is
+    // ever blocked, and its default is to be ignored). A handler resets at
+    // exec by itself, and nothing here is ignored.
+    const none = std.posix.sigemptyset();
+    var kept: std.posix.sigset_t = undefined;
+    std.posix.sigprocmask(std.posix.SIG.SETMASK, &none, &kept);
+    defer std.posix.sigprocmask(std.posix.SIG.SETMASK, &kept, null);
     var child = std.process.spawn(io, .{
         .argv = &.{ "/bin/sh", "-c", command },
         .cwd = if (cwd.len == 0) .inherit else .{ .path = cwd },