A Dump into a DumpDir that is no directory says so; the doc says a missing last directory is made

DumpDir /dev/null said no such directory though it is there, and the doc claimed a missing DumpDir always fails, where its last component is made at the Dump.

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

1 files changed, 9 insertions, 3 deletions

diff --git a/src/exec.zig b/src/exec.zig
index fdb9bdb7..683b2f04 100644
--- a/src/exec.zig
+++ b/src/exec.zig
@@ -397,12 +397,18 @@ pub fn isDirectory(path: []const u8) bool {
 
 /// Whether `path` is a plain file on this host, the turn out while it asks.
 pub fn isFile(path: []const u8) bool {
+    return kindOf(path) == .file;
+}
+
+/// What `path` is on this host, null when it is not there; the turn out
+/// while it asks.
+pub fn kindOf(path: []const u8) ?std.Io.File.Kind {
     var buf: [4096]u8 = undefined;
-    const z = std.fmt.bufPrintSentinel(&buf, "{s}", .{path}, 0) catch return false;
+    const z = std.fmt.bufPrintSentinel(&buf, "{s}", .{path}, 0) catch return null;
     pardes.turn.yield();
     defer pardes.turn.back();
-    const stat = std.Io.Dir.cwd().statFile(std.Io.Threaded.global_single_threaded.io(), z, .{}) catch return false;
-    return stat.kind == .file;
+    const stat = std.Io.Dir.cwd().statFile(std.Io.Threaded.global_single_threaded.io(), z, .{}) catch return null;
+    return stat.kind;
 }
 
 /// With `BootShell replace`, a doc landing in `col` closes a lone pristine