[jay-tau]

Fixes #346.

#347 fixed items 1 and 2 of #346. This fixes the other four, in four commits on top of it:

1. File names that aren't UTF-8 (item 5). zenity 4 prints the bytes of each path, and rfd decoded them as UTF-8, so such a name made the dialog return None. The output is now kept as bytes. This removes ZenityError::FromUtf8Error, which isn't public.
2. Cancel (item 4). pick_files and pick_folders return None when the zenity dialog is cancelled, as the portal branch does since Minor xdg portal improvements #323, rather than Some(vec![]).
3. Filter names with | (item 3). zenity ends a filter's name at the first | and has no way to escape it, so a | in a name is now shown as /. A lookalike such as ∣ (U+2223) would read better, but zenity converts --file-filter arguments from the locale's charset, and with LC_ALL=C, zenity 4.2.2 exited without showing a dialog when a filter name wasn't ASCII.
4. Starting directory (item 6). The directory is passed as --filename '<dir>/', or joined with the name from set_file_name, rather than as zenity's working directory. With GTK's default file chooser settings, open and folder dialogs could start on Recent instead of the working directory (save dialogs already started there), while zenity opens the folder of a --filename path itself. zenity 3 only does this for an absolute path, so a relative directory is made absolute first, and zenity 4 ignores /, which is its own base name, so the root is passed as /./. Since zenity no longer starts in the directory, one that doesn't exist no longer stops it from starting. On master, the chdir fails and the dialog returns None without opening. A .. in the directory is now resolved by zenity without following symlinks, like cd .. in a shell, where chdir followed them.

Some limits remain. With the newline separator from #347, a selected name that contains a newline is still split: a file named x followed by a newline, selected with y.txt, gives [".../x", "", ".../y.txt"]. A separator such as /./ would avoid that, because GTK gives zenity canonical absolute paths, which have no . components; I can send it separately if you'd like. zenity 3 converts each path with g_filename_to_utf8 before printing it; a failed conversion can print (null), and a successful one from a legacy filename encoding can change the path's bytes. Before GLib 2.86, g_print also converts zenity's piped output when the locale's charset isn't UTF-8; zenity 4.2.2 with GLib 2.90.1 printed the bytes unchanged, also with LC_ALL=C. zenity 4 can also print (null) for a selected file that has no local path.

Testing

I built a small program against this branch and against master (98d6cf2) with default-features = false, features = ["xdg-portal"] and ran it in a headless mutter session on a private session bus without a portal service, so rfd used zenity 4.2.2 (GTK 4.24.1). Keys and clicks were sent with XTest. The program's working directory was the parent of the test folders, except for a second missing-folder check, which ran from a different existing folder to tell the parent folder apart from the working directory. For the first rows, GTK's file chooser was set to startup-mode='cwd' so that master opened the test folder; the set_directory rows use GTK's default, recent.

Case	master	This branch
pick_files, pick_file: caf\xE9.txt; pick_folder: caf\xE9	None	the path
Escape in pick_files, pick_folders	Some([])	None
add_filter("Text | Markdown", &["txt", "md"])	filter "Text", file Markdown listed	filter "Text / Markdown", Markdown hidden, also with LC_ALL=C
set_directory with pick_files, pick_folder, set_file_name, and a relative path	opens Recent	opens the folder
set_directory("/")	opens / with startup-mode='cwd'	opens / with either setting
set_directory with a folder that doesn't exist	no dialog, None	dialog opens in the parent folder
save_file with set_file_name("report ") and set_directory	".../report"	".../report" (GTK removes the space itself)
pick_files, pick_folders: names with | or a trailing space	correct (#347)	correct

AsyncFileDialog::pick_files and pick_folders gave the same results as the sync calls for the | names and for Escape.

New unit tests cover reading output that isn't UTF-8 and the zenity arguments; the two argument tests fail on master. With --no-default-features --features xdg-portal, cargo test, cargo clippy and cargo fmt --check pass on each commit with no warnings. The default features, --no-default-features --features gtk3 and --no-default-features --features gtk4 build. The tests also pass with Rust 1.89 (with --ignore-rust-version), so nothing needs more than the 1.92 MSRV.

I didn't run zenity 3; what this says about it comes from its 3.44.5 source. I also didn't test on a BSD.