Merge pull request #1780 from gpanders/open-error-log

os: log stderr from open command

src/os/open.zig

@@ -3,6 +3,9 @@ const builtin = @import("builtin");
 const Allocator = std.mem.Allocator;
 
 /// Open a URL in the default handling application.
+///
+/// Any output on stderr is logged as a warning in the application logs.
+/// Output on stdout is ignored.
 pub fn open(alloc: Allocator, url: []const u8) !void {
     const argv = switch (builtin.os.tag) {
         .linux => &.{ "xdg-open", url },
@@ -13,5 +16,25 @@ pub fn open(alloc: Allocator, url: []const u8) !void {
     };
 
     var exe = std.process.Child.init(argv, alloc);
-    try exe.spawn();
+
+    // Pipe stdout/stderr so we can collect output from the command
+    exe.stdout_behavior = .Pipe;
+    exe.stderr_behavior = .Pipe;
+    var stdout = std.ArrayList(u8).init(alloc);
+    var stderr = std.ArrayList(u8).init(alloc);
+    defer {
+        stdout.deinit();
+        stderr.deinit();
+    }
+
+    // 50 KiB is the default value used by std.process.Child.run
+    const output_max_size = 50 * 1024;
+
+    try exe.spawn();
+    try exe.collectOutput(&stdout, &stderr, output_max_size);
+    _ = try exe.wait();
+
+    // If we have any stderr output we log it. This makes it easier for
+    // users to debug why some open commands may not work as expected.
+    if (stderr.items.len > 0) std.log.err("open stderr={s}", .{stderr.items});
 }