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website/content/posts/impossibly-deep-bug.md
Anthony Wang 694704d0fc
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Fix #2: Make a lot of posts drafts
2022-07-21 15:34:22 -05:00

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title date draft description type tags
The Impossibly Deep Bug 2022-06-12T12:08:22-05:00 true Chasing down a bug that only keeps on getting deeper post
bug
kde
wayland
micro
software

Since the past few weeks, my muscle memory has really begun to hate me. I had switched all my systems over to Wayland because X11 bad and I had switched my CLI text editor from Vim to Micro because constantly looking up Vim shortcuts makes me slower.

One of the things I can never remember how to do in Vim is copy and paste to the system clipboard. It's some permutation of *"+y right? Something like that. However, with Micro, you already know how to copy and paste (because it's literally just Ctrl+C Ctrl+V and your grandma could figure that out). Also, Vim doesn't support copying and pasting in Wayland by default unless you add some magic to your ~/.vimrc, while Micro only requires you to install the (generally incredibly useful) wl-clipboard utility and it'll just work™.

But...

Yeah, that just sounds too good to be true. Wayland has a nifty little tool called Waypipe that's just like X11 forwarding plus VirtualGL (by the way VirtualGL is one of those evil softwares that breaks regularly and laughs when you try to debug it). You get GPU-accelerated remote windows and it's an indispensible feature in my daily workflow. However, Micro copy paste behaves incredibly strangely in a Waypipe remote session.

First of all, when you try to copy, Waypipe spits out a very annoying informational line that screws over your nice TUI app, but you can easily comment it out in the Waypipe source and recompile.

However, there's a deeper issue: after copying, you can paste into your terminal emulator just fine, but trying to paste into anything else will just lead to pasting nothing. And after you close the Waypipe session, it goes back to pasting whatever was originally in your clipboard.

Even stranger, Micro claims to use wl-clipboard's wl-copy for copying to the clipboard, and running wl-copy hello in a Waypipe session works perfectly. Perfectly!

Diving deeper

OK, that's pretty spooky, so let's take a look at the Micro source code. internal/clipboard/clipboard.go is the relevant file, but oops, it just uses another library zyedidia/clipboard for the hard lifting so let's read that library instead. clipboard_unix.go is the file we want in that library, and after a close inspection, we do run wl-copy with os.exec, but the text we want to copy is piped into wl-copy.

Yay, progress! Running echo hello | wl-copy behaves in the same spooky way as Micro, so we know the bug isn't in either Micro or zyedidia/clipboard.

So it certainly smells like the bug is in wl-clipboard, so I went ahead and filed an issue there.

Here's what happened next:

Me

When running wl-copy on a remote server that you've connected to using Waypipe, copying text from stdin does not work:

me@ThinkPad-X1-Yoga-Gen-6 ~> waypipe ssh exozyme  # Connect to the remote machine with Waypipe
Welcome to fish, the friendly interactive shell
Type help for instructions on how to use fish
ta180m@exozyme ~> echo hello | wl-copy  # Doesn't work

However, copying text if it's specified in the command does work:

me@ThinkPad-X1-Yoga-Gen-6 ~> waypipe ssh exozyme  # Connect to the remote machine with Waypipe
Welcome to fish, the friendly interactive shell
Type help for instructions on how to use fish
ta180m@exozyme ~> wl-copy hello  # Does work

In the first case, I'm not really sure what gets copied to the clipboard, but when I try pasting, nothing is pasted while Waypipe is still open. Then if I close Waypipe and the remote connection and try pasting, the thing originally in my clipboard is pasted. For instance:

me@ThinkPad-X1-Yoga-Gen-6 ~> wl-paste
A
me@ThinkPad-X1-Yoga-Gen-6 ~> waypipe ssh exozyme  # Connect to the remote machine with Waypipe
Welcome to fish, the friendly interactive shell
Type help for instructions on how to use fish
ta180m@exozyme ~> wl-paste
A
ta180m@exozyme ~> echo B | wl-copy  # Doesn't work
ta180m@exozyme ~> wl-paste  # This only works in the current shell, if I open up a new one and try wl-paste, it pastes A
B
ta180m@exozyme ~> exit
Connection to exozy.me closed.
me@ThinkPad-X1-Yoga-Gen-6 ~> wl-paste
A

Any idea what's going on here?

Maintainer

Hmm, not sure, I'm not familiar with how waypipe works. Maybe WAYLAND_DEBUG=1 on wl-copy could clear something up?

Me

This is the output of echo B | WAYLAND_DEBUG=1 wl-copy in Waypipe:

[4030950.284]  -> wl_display@1.get_registry(new id wl_registry@2)
[4030950.314]  -> wl_display@1.sync(new id wl_callback@3)
[4030994.575] wl_display@1.delete_id(3)
[4030994.585] wl_registry@2.global(1, "wl_compositor", 4)
[4030994.592]  -> wl_registry@2.bind(1, "wl_compositor", 2, new id [unknown]@4)
[4030994.602] wl_registry@2.global(2, "zwp_tablet_manager_v2", 1)
[4030994.608] wl_registry@2.global(3, "zwp_keyboard_shortcuts_inhibit_manager_v1", 1)
[4030994.615] wl_registry@2.global(5, "xdg_wm_base", 3)
[4030994.621]  -> wl_registry@2.bind(5, "xdg_wm_base", 1, new id [unknown]@5)
[4030994.630] wl_registry@2.global(6, "zwlr_layer_shell_v1", 3)
[4030994.636] wl_registry@2.global(7, "zxdg_decoration_manager_v1", 1)
[4030994.642] wl_registry@2.global(8, "wp_viewporter", 1)
[4030994.648] wl_registry@2.global(9, "wl_shm", 1)
[4030994.654]  -> wl_registry@2.bind(9, "wl_shm", 1, new id [unknown]@6)
[4030994.663] wl_registry@2.global(10, "wl_seat", 7)
[4030994.669]  -> wl_registry@2.bind(10, "wl_seat", 2, new id [unknown]@7)
[4030994.678] wl_registry@2.global(11, "zwp_pointer_gestures_v1", 3)
[4030994.684] wl_registry@2.global(12, "zwp_pointer_constraints_v1", 1)
[4030994.690] wl_registry@2.global(13, "zwp_relative_pointer_manager_v1", 1)
[4030994.696] wl_registry@2.global(14, "wl_data_device_manager", 3)
[4030994.702]  -> wl_registry@2.bind(14, "wl_data_device_manager", 1, new id [unknown]@8)
[4030994.711] wl_registry@2.global(15, "zwlr_data_control_manager_v1", 2)
[4030994.717]  -> wl_registry@2.bind(15, "zwlr_data_control_manager_v1", 2, new id [unknown]@9)
[4030994.725] wl_registry@2.global(16, "zwp_primary_selection_device_manager_v1", 1)
[4030994.732]  -> wl_registry@2.bind(16, "zwp_primary_selection_device_manager_v1", 1, new id [unknown]@10)
[4030994.740] wl_registry@2.global(17, "org_kde_kwin_idle", 1)
[4030994.746] wl_registry@2.global(18, "zwp_idle_inhibit_manager_v1", 1)
[4030994.752] wl_registry@2.global(19, "org_kde_plasma_shell", 6)
[4030994.759] wl_registry@2.global(20, "org_kde_kwin_appmenu_manager", 1)
[4030994.765] wl_registry@2.global(21, "org_kde_kwin_server_decoration_palette_manager", 1)
[4030994.771] wl_registry@2.global(23, "org_kde_plasma_virtual_desktop_management", 2)
[4030994.777] wl_registry@2.global(25, "org_kde_kwin_shadow_manager", 2)
[4030994.783] wl_registry@2.global(26, "org_kde_kwin_dpms_manager", 1)
[4030994.789] wl_registry@2.global(27, "org_kde_kwin_server_decoration_manager", 1)
[4030994.795] wl_registry@2.global(28, "kde_output_management_v2", 2)
[4030994.801] wl_registry@2.global(29, "kde_primary_output_v1", 1)
[4030994.807] wl_registry@2.global(30, "zxdg_output_manager_v1", 3)
[4030994.813] wl_registry@2.global(31, "wl_subcompositor", 1)
[4030994.819] wl_registry@2.global(32, "zxdg_exporter_v2", 1)
[4030994.826] wl_registry@2.global(33, "zxdg_importer_v2", 1)
[4030994.832] wl_registry@2.global(36, "xdg_activation_v1", 1)
[4030994.838] wl_registry@2.global(37, "wp_drm_lease_device_v1", 1)
[4030994.844] wl_registry@2.global(40, "wl_drm", 2)
[4030994.850] wl_registry@2.global(41, "zwp_linux_dmabuf_v1", 3)
[4030994.856] wl_registry@2.global(42, "kde_output_device_v2", 2)
[4030994.862] wl_registry@2.global(44, "zwp_text_input_manager_v2", 1)
[4030994.868] wl_registry@2.global(45, "zwp_text_input_manager_v3", 1)
[4030994.874] wl_registry@2.global(46, "org_kde_kwin_contrast_manager", 2)
[4030994.880] wl_registry@2.global(47, "org_kde_kwin_blur_manager", 1)
[4030994.886] wl_registry@2.global(48, "org_kde_kwin_slide_manager", 1)
[4030994.892] wl_registry@2.global(49, "kde_output_device_v2", 2)
[4030994.898] wl_registry@2.global(50, "wl_output", 3)
[4030994.905] wl_callback@3.done(1256)
[4030994.908]  -> wl_display@1.sync(new id wl_callback@3)
[4030998.044] wl_display@1.delete_id(3)
[4030998.051] wl_seat@7.capabilities(7)
[4030998.055] wl_seat@7.name("")
[4030998.059] wl_callback@3.done(1256)
[4030998.064]  -> zwlr_data_control_manager_v1@9.get_data_device(new id zwlr_data_control_device_v1@3, wl_seat@7)
[4031003.612]  -> zwlr_data_control_manager_v1@9.create_data_source(new id zwlr_data_control_source_v1@11)
[4031003.627]  -> zwlr_data_control_source_v1@11.offer("˜¢fV")
[4031003.630]  -> zwlr_data_control_device_v1@3.set_selection(zwlr_data_control_source_v1@11)
[4031003.633]  -> wl_display@1.sync(new id wl_callback@12)
[4031006.384] wl_display@1.delete_id(12)
[4031006.390] zwlr_data_control_device_v1@3.data_offer(new id zwlr_data_control_offer_v1@4278190080)
[4031006.395] zwlr_data_control_offer_v1@4278190080.offer("text/plain")
[4031006.399] zwlr_data_control_offer_v1@4278190080.offer("text/plain")
[4031006.403] zwlr_data_control_offer_v1@4278190080.offer("text/plain;charset=utf-8")
[4031006.407] zwlr_data_control_offer_v1@4278190080.offer("TEXT")
[4031006.411] zwlr_data_control_offer_v1@4278190080.offer("STRING")
[4031006.414] zwlr_data_control_offer_v1@4278190080.offer("UTF8_STRING")
[4031006.418] zwlr_data_control_device_v1@3.selection(zwlr_data_control_offer_v1@4278190080)
[4031006.422] zwlr_data_control_device_v1@3.data_offer(new id zwlr_data_control_offer_v1@4278190081)
[4031006.427] zwlr_data_control_offer_v1@4278190081.offer("text/plain")
[4031006.431] zwlr_data_control_offer_v1@4278190081.offer("text/html")
[4031006.435] zwlr_data_control_offer_v1@4278190081.offer("text/plain;charset=utf-8")
[4031006.439] zwlr_data_control_device_v1@3.primary_selection(zwlr_data_control_offer_v1@4278190081)
[4031006.442] zwlr_data_control_device_v1@3.data_offer(new id zwlr_data_control_offer_v1@4278190082)
[4031006.447] zwlr_data_control_offer_v1@4278190082.offer("ￜￜfV")
[4031006.451] zwlr_data_control_device_v1@3.selection(zwlr_data_control_offer_v1@4278190082)
[4031006.455] wl_callback@12.done(1256)
[4035132.398] zwlr_data_control_source_v1@11.cancelled()

And this is the output of WAYLAND_DEBUG=1 wl-copy B in Waypipe:

[4158623.296]  -> wl_display@1.get_registry(new id wl_registry@2)
[4158623.319]  -> wl_display@1.sync(new id wl_callback@3)
[4158669.862] wl_display@1.delete_id(3)
[4158669.875] wl_registry@2.global(1, "wl_compositor", 4)
[4158669.883]  -> wl_registry@2.bind(1, "wl_compositor", 2, new id [unknown]@4)
[4158669.893] wl_registry@2.global(2, "zwp_tablet_manager_v2", 1)
[4158669.899] wl_registry@2.global(3, "zwp_keyboard_shortcuts_inhibit_manager_v1", 1)
[4158669.905] wl_registry@2.global(5, "xdg_wm_base", 3)
[4158669.912]  -> wl_registry@2.bind(5, "xdg_wm_base", 1, new id [unknown]@5)
[4158669.920] wl_registry@2.global(6, "zwlr_layer_shell_v1", 3)
[4158669.926] wl_registry@2.global(7, "zxdg_decoration_manager_v1", 1)
[4158669.933] wl_registry@2.global(8, "wp_viewporter", 1)
[4158669.939] wl_registry@2.global(9, "wl_shm", 1)
[4158669.945]  -> wl_registry@2.bind(9, "wl_shm", 1, new id [unknown]@6)
[4158669.953] wl_registry@2.global(10, "wl_seat", 7)
[4158669.959]  -> wl_registry@2.bind(10, "wl_seat", 2, new id [unknown]@7)
[4158669.968] wl_registry@2.global(11, "zwp_pointer_gestures_v1", 3)
[4158669.974] wl_registry@2.global(12, "zwp_pointer_constraints_v1", 1)
[4158669.980] wl_registry@2.global(13, "zwp_relative_pointer_manager_v1", 1)
[4158669.986] wl_registry@2.global(14, "wl_data_device_manager", 3)
[4158669.992]  -> wl_registry@2.bind(14, "wl_data_device_manager", 1, new id [unknown]@8)
[4158670.001] wl_registry@2.global(15, "zwlr_data_control_manager_v1", 2)
[4158670.009]  -> wl_registry@2.bind(15, "zwlr_data_control_manager_v1", 2, new id [unknown]@9)
[4158670.018] wl_registry@2.global(16, "zwp_primary_selection_device_manager_v1", 1)
[4158670.024]  -> wl_registry@2.bind(16, "zwp_primary_selection_device_manager_v1", 1, new id [unknown]@10)
[4158670.033] wl_registry@2.global(17, "org_kde_kwin_idle", 1)
[4158670.039] wl_registry@2.global(18, "zwp_idle_inhibit_manager_v1", 1)
[4158670.045] wl_registry@2.global(19, "org_kde_plasma_shell", 6)
[4158670.051] wl_registry@2.global(20, "org_kde_kwin_appmenu_manager", 1)
[4158670.057] wl_registry@2.global(21, "org_kde_kwin_server_decoration_palette_manager", 1)
[4158670.063] wl_registry@2.global(23, "org_kde_plasma_virtual_desktop_management", 2)
[4158670.069] wl_registry@2.global(25, "org_kde_kwin_shadow_manager", 2)
[4158670.075] wl_registry@2.global(26, "org_kde_kwin_dpms_manager", 1)
[4158670.081] wl_registry@2.global(27, "org_kde_kwin_server_decoration_manager", 1)
[4158670.088] wl_registry@2.global(28, "kde_output_management_v2", 2)
[4158670.094] wl_registry@2.global(29, "kde_primary_output_v1", 1)
[4158670.100] wl_registry@2.global(30, "zxdg_output_manager_v1", 3)
[4158670.106] wl_registry@2.global(31, "wl_subcompositor", 1)
[4158670.112] wl_registry@2.global(32, "zxdg_exporter_v2", 1)
[4158670.118] wl_registry@2.global(33, "zxdg_importer_v2", 1)
[4158670.124] wl_registry@2.global(36, "xdg_activation_v1", 1)
[4158670.130] wl_registry@2.global(37, "wp_drm_lease_device_v1", 1)
[4158670.136] wl_registry@2.global(40, "wl_drm", 2)
[4158670.142] wl_registry@2.global(41, "zwp_linux_dmabuf_v1", 3)
[4158670.148] wl_registry@2.global(42, "kde_output_device_v2", 2)
[4158670.154] wl_registry@2.global(44, "zwp_text_input_manager_v2", 1)
[4158670.160] wl_registry@2.global(45, "zwp_text_input_manager_v3", 1)
[4158670.166] wl_registry@2.global(46, "org_kde_kwin_contrast_manager", 2)
[4158670.172] wl_registry@2.global(47, "org_kde_kwin_blur_manager", 1)
[4158670.178] wl_registry@2.global(48, "org_kde_kwin_slide_manager", 1)
[4158670.185] wl_registry@2.global(49, "kde_output_device_v2", 2)
[4158670.191] wl_registry@2.global(50, "wl_output", 3)
[4158670.197] wl_callback@3.done(2133)
[4158670.200]  -> wl_display@1.sync(new id wl_callback@3)
[4158671.921] wl_display@1.delete_id(3)
[4158671.925] wl_seat@7.capabilities(7)
[4158671.928] wl_seat@7.name("")
[4158671.932] wl_callback@3.done(2133)
[4158671.935]  -> zwlr_data_control_manager_v1@9.get_data_device(new id zwlr_data_control_device_v1@3, wl_seat@7)
[4158671.942]  -> zwlr_data_control_manager_v1@9.create_data_source(new id zwlr_data_control_source_v1@11)
[4158671.952]  -> zwlr_data_control_source_v1@11.offer("text/plain")
[4158671.955]  -> zwlr_data_control_source_v1@11.offer("text/plain;charset=utf-8")
[4158671.958]  -> zwlr_data_control_source_v1@11.offer("TEXT")
[4158671.961]  -> zwlr_data_control_source_v1@11.offer("STRING")
[4158671.964]  -> zwlr_data_control_source_v1@11.offer("UTF8_STRING")
[4158671.967]  -> zwlr_data_control_device_v1@3.set_selection(zwlr_data_control_source_v1@11)
[4158671.971]  -> wl_display@1.sync(new id wl_callback@12)
[4158673.699] wl_display@1.delete_id(12)
[4158673.702] zwlr_data_control_device_v1@3.data_offer(new id zwlr_data_control_offer_v1@4278190080)
[4158673.706] zwlr_data_control_offer_v1@4278190080.offer("UTF8_STRING")
[4158673.710] zwlr_data_control_offer_v1@4278190080.offer("COMPOUND_TEXT")
[4158673.713] zwlr_data_control_offer_v1@4278190080.offer("TEXT")
[4158673.715] zwlr_data_control_offer_v1@4278190080.offer("STRING")
[4158673.718] zwlr_data_control_offer_v1@4278190080.offer("text/plain;charset=utf-8")
[4158673.721] zwlr_data_control_offer_v1@4278190080.offer("text/plain")
[4158673.724] zwlr_data_control_offer_v1@4278190080.offer("SAVE_TARGETS")
[4158673.727] zwlr_data_control_device_v1@3.selection(zwlr_data_control_offer_v1@4278190080)
[4158673.730] zwlr_data_control_device_v1@3.data_offer(new id zwlr_data_control_offer_v1@4278190081)
[4158673.734] zwlr_data_control_offer_v1@4278190081.offer("UTF8_STRING")
[4158673.737] zwlr_data_control_offer_v1@4278190081.offer("COMPOUND_TEXT")
[4158673.740] zwlr_data_control_offer_v1@4278190081.offer("TEXT")
[4158673.743] zwlr_data_control_offer_v1@4278190081.offer("STRING")
[4158673.746] zwlr_data_control_offer_v1@4278190081.offer("text/plain;charset=utf-8")
[4158673.749] zwlr_data_control_offer_v1@4278190081.offer("text/plain")
[4158673.752] zwlr_data_control_device_v1@3.primary_selection(zwlr_data_control_offer_v1@4278190081)
[4158673.755] zwlr_data_control_device_v1@3.data_offer(new id zwlr_data_control_offer_v1@4278190082)
[4158673.758] zwlr_data_control_offer_v1@4278190082.offer("text/plain")
[4158673.761] zwlr_data_control_offer_v1@4278190082.offer("text/plain;charset=utf-8")
[4158673.764] zwlr_data_control_offer_v1@4278190082.offer("TEXT")
[4158673.767] zwlr_data_control_offer_v1@4278190082.offer("STRING")
[4158673.770] zwlr_data_control_offer_v1@4278190082.offer("UTF8_STRING")
[4158673.773] zwlr_data_control_device_v1@3.selection(zwlr_data_control_offer_v1@4278190082)
[4158673.776] wl_callback@12.done(2133)
[4158674.051] zwlr_data_control_source_v1@11.send("text/plain;charset=utf-8", fd 4)
[4158675.799] zwlr_data_control_source_v1@11.send("text/plain;charset=utf-8", fd 4)
[4165362.697] zwlr_data_control_source_v1@11.cancelled()

And this is the output of echo B | WAYLAND_DEBUG=1 wl-copy in a local shell:

[4021884.136]  -> wl_display@1.get_registry(new id wl_registry@2)
[4021884.184]  -> wl_display@1.sync(new id wl_callback@3)
[4021886.871] wl_display@1.delete_id(3)
[4021886.899] wl_registry@2.global(1, "wl_compositor", 4)
[4021886.937]  -> wl_registry@2.bind(1, "wl_compositor", 2, new id [unknown]@4)
[4021886.984] wl_registry@2.global(2, "zwp_tablet_manager_v2", 1)
[4021887.017] wl_registry@2.global(3, "zwp_keyboard_shortcuts_inhibit_manager_v1", 1)
[4021887.050] wl_registry@2.global(5, "xdg_wm_base", 3)
[4021887.080]  -> wl_registry@2.bind(5, "xdg_wm_base", 1, new id [unknown]@5)
[4021887.124] wl_registry@2.global(6, "zwlr_layer_shell_v1", 3)
[4021887.155] wl_registry@2.global(7, "zxdg_decoration_manager_v1", 1)
[4021887.185] wl_registry@2.global(8, "wp_viewporter", 1)
[4021887.216] wl_registry@2.global(9, "wl_shm", 1)
[4021887.247]  -> wl_registry@2.bind(9, "wl_shm", 1, new id [unknown]@6)
[4021887.290] wl_registry@2.global(10, "wl_seat", 7)
[4021887.321]  -> wl_registry@2.bind(10, "wl_seat", 2, new id [unknown]@7)
[4021887.365] wl_registry@2.global(11, "zwp_pointer_gestures_v1", 3)
[4021887.397] wl_registry@2.global(12, "zwp_pointer_constraints_v1", 1)
[4021887.427] wl_registry@2.global(13, "zwp_relative_pointer_manager_v1", 1)
[4021887.458] wl_registry@2.global(14, "wl_data_device_manager", 3)
[4021887.490]  -> wl_registry@2.bind(14, "wl_data_device_manager", 1, new id [unknown]@8)
[4021887.535] wl_registry@2.global(15, "zwlr_data_control_manager_v1", 2)
[4021887.567]  -> wl_registry@2.bind(15, "zwlr_data_control_manager_v1", 2, new id [unknown]@9)
[4021887.611] wl_registry@2.global(16, "zwp_primary_selection_device_manager_v1", 1)
[4021887.642]  -> wl_registry@2.bind(16, "zwp_primary_selection_device_manager_v1", 1, new id [unknown]@10)
[4021887.688] wl_registry@2.global(17, "org_kde_kwin_idle", 1)
[4021887.720] wl_registry@2.global(18, "zwp_idle_inhibit_manager_v1", 1)
[4021887.752] wl_registry@2.global(19, "org_kde_plasma_shell", 6)
[4021887.785] wl_registry@2.global(20, "org_kde_kwin_appmenu_manager", 1)
[4021887.821] wl_registry@2.global(21, "org_kde_kwin_server_decoration_palette_manager", 1)
[4021887.853] wl_registry@2.global(23, "org_kde_plasma_virtual_desktop_management", 2)
[4021887.883] wl_registry@2.global(25, "org_kde_kwin_shadow_manager", 2)
[4021887.915] wl_registry@2.global(26, "org_kde_kwin_dpms_manager", 1)
[4021887.945] wl_registry@2.global(27, "org_kde_kwin_server_decoration_manager", 1)
[4021887.978] wl_registry@2.global(28, "kde_output_management_v2", 2)
[4021888.009] wl_registry@2.global(29, "kde_primary_output_v1", 1)
[4021888.043] wl_registry@2.global(30, "zxdg_output_manager_v1", 3)
[4021888.075] wl_registry@2.global(31, "wl_subcompositor", 1)
[4021888.107] wl_registry@2.global(32, "zxdg_exporter_v2", 1)
[4021888.139] wl_registry@2.global(33, "zxdg_importer_v2", 1)
[4021888.170] wl_registry@2.global(36, "xdg_activation_v1", 1)
[4021888.202] wl_registry@2.global(37, "wp_drm_lease_device_v1", 1)
[4021888.234] wl_registry@2.global(40, "wl_drm", 2)
[4021888.266] wl_registry@2.global(41, "zwp_linux_dmabuf_v1", 4)
[4021888.297] wl_registry@2.global(42, "kde_output_device_v2", 2)
[4021888.328] wl_registry@2.global(44, "zwp_text_input_manager_v2", 1)
[4021888.359] wl_registry@2.global(45, "zwp_text_input_manager_v3", 1)
[4021888.391] wl_registry@2.global(46, "org_kde_kwin_contrast_manager", 2)
[4021888.424] wl_registry@2.global(47, "org_kde_kwin_blur_manager", 1)
[4021888.455] wl_registry@2.global(48, "org_kde_kwin_slide_manager", 1)
[4021888.487] wl_registry@2.global(49, "kde_output_device_v2", 2)
[4021888.519] wl_registry@2.global(50, "wl_output", 3)
[4021888.552] wl_callback@3.done(1215)
[4021888.567]  -> wl_display@1.sync(new id wl_callback@3)
[4021888.657] wl_display@1.delete_id(3)
[4021888.673] wl_seat@7.capabilities(7)
[4021888.687] wl_seat@7.name("")
[4021888.704] wl_callback@3.done(1215)
[4021888.718]  -> zwlr_data_control_manager_v1@9.get_data_device(new id zwlr_data_control_device_v1@3, wl_seat@7)
[4021898.743]  -> zwlr_data_control_manager_v1@9.create_data_source(new id zwlr_data_control_source_v1@11)
[4021898.807]  -> zwlr_data_control_source_v1@11.offer("text/plain")
[4021898.819]  -> zwlr_data_control_source_v1@11.offer("text/plain")
[4021898.833]  -> zwlr_data_control_source_v1@11.offer("text/plain;charset=utf-8")
[4021898.847]  -> zwlr_data_control_source_v1@11.offer("TEXT")
[4021898.861]  -> zwlr_data_control_source_v1@11.offer("STRING")
[4021898.875]  -> zwlr_data_control_source_v1@11.offer("UTF8_STRING")
[4021898.893]  -> zwlr_data_control_device_v1@3.set_selection(zwlr_data_control_source_v1@11)
[4021898.909]  -> wl_display@1.sync(new id wl_callback@12)
[4021899.054] wl_display@1.delete_id(12)
[4021899.082] zwlr_data_control_device_v1@3.data_offer(new id zwlr_data_control_offer_v1@4278190080)
[4021899.098] zwlr_data_control_offer_v1@4278190080.offer("text/plain")
[4021899.112] zwlr_data_control_offer_v1@4278190080.offer("text/plain")
[4021899.124] zwlr_data_control_offer_v1@4278190080.offer("text/plain;charset=utf-8")
[4021899.137] zwlr_data_control_offer_v1@4278190080.offer("TEXT")
[4021899.150] zwlr_data_control_offer_v1@4278190080.offer("STRING")
[4021899.164] zwlr_data_control_offer_v1@4278190080.offer("UTF8_STRING")
[4021899.176] zwlr_data_control_device_v1@3.selection(zwlr_data_control_offer_v1@4278190080)
[4021899.222] zwlr_data_control_device_v1@3.data_offer(new id zwlr_data_control_offer_v1@4278190081)
[4021899.248] zwlr_data_control_offer_v1@4278190081.offer("text/plain")
[4021899.260] zwlr_data_control_offer_v1@4278190081.offer("text/html")
[4021899.273] zwlr_data_control_offer_v1@4278190081.offer("text/plain;charset=utf-8")
[4021899.286] zwlr_data_control_device_v1@3.primary_selection(zwlr_data_control_offer_v1@4278190081)
[4021899.300] zwlr_data_control_device_v1@3.data_offer(new id zwlr_data_control_offer_v1@4278190082)
[4021899.318] zwlr_data_control_offer_v1@4278190082.offer("text/plain")
[4021899.331] zwlr_data_control_offer_v1@4278190082.offer("text/plain")
[4021899.343] zwlr_data_control_offer_v1@4278190082.offer("text/plain;charset=utf-8")
[4021899.355] zwlr_data_control_offer_v1@4278190082.offer("TEXT")
[4021899.367] zwlr_data_control_offer_v1@4278190082.offer("STRING")
[4021899.380] zwlr_data_control_offer_v1@4278190082.offer("UTF8_STRING")
[4021899.392] zwlr_data_control_device_v1@3.selection(zwlr_data_control_offer_v1@4278190082)
[4021899.408] wl_callback@12.done(1215)
[4021899.575] zwlr_data_control_source_v1@11.send("text/plain;charset=utf-8", fd 8)
[4021900.191] zwlr_data_control_source_v1@11.send("text/plain;charset=utf-8", fd 8)
[4030969.780] zwlr_data_control_source_v1@11.cancelled()

In the first case, wl-copy seems to be copying control characters, which is why pasting doesn't result in anything being pasted.

Maintainer

That looks rather strange, especially considering it's the MIME type that gets weird characters, not the contents...

Me

Manually specifying the MIME type with echo B | WAYLAND_DEBUG=1 wl-copy -t text/plain-text works in Waypipe. How is the MIME type normally inferred?

Me

I think I made more progress: wl-clipboard uses xdg-mime query filetype for inferring the MIME type right? If so, xdg-mime query filetype somefile works in a local shell but does not output anything at all in a Waypipe remote session.

Aha!

So wl-clipboard is actually an innocent victim too, just like Micro and the clipboard library! xdg-mime is the real culprit here, so maybe time to file an issue for them?

Not so fast, let's take a glance at the xdg-mime source code. Here's the relevant lines:

info_kde()
{
    if [ -n "${KDE_SESSION_VERSION}" ]; then
      case "${KDE_SESSION_VERSION}" in
        4)
          DEBUG 1 "Running kmimetypefinder \"$1\""
          kmimetypefinder "$1" 2>/dev/null | head -n 1
        ;;
        5)
          DEBUG 1 "Running kmimetypefinder${KDE_SESSION_VERSION} \"$1\""
          kmimetypefinder${KDE_SESSION_VERSION} "$1" 2>/dev/null | head -n 1
        ;;
      esac
    else
        DEBUG 1 "Running kfile \"$1\""
        kfile "$1" 2> /dev/null | head -n 1 | cut -d "(" -f 2 | cut -d ")" -f 1
    fi

    if [ $? -eq 0 ]; then
        exit_success
    else
        exit_failure_operation_failed
    fi
}

xdg-mime thinks I'm using KDE 4 because this is a remote session with no environment variables set! Well, actually, I do have one variable set: XDG_CURRENT_DESKTOP=KDE in my ~/.ssh/environment so apps run over Waypipe know to use KDE theming. xdg-mime thinks I'm an old-timer still on KDE 4 and uses the KDE 4 kfile command to detect the MIME type. But since I'm running hemorrhaging-edge KDE 5.soon-to-be-25.0 on Arch, that kfile command doesn't exist and xdg-mime interally errors and outputs nothing. Setting KDE_SESSION_VERSION=5 in ~/.ssh/environment makes copying text from stdin work in Waypipe! Case closed, 🎉

I'll end with a TL;DR, since I copied this verbatim from that wl-clipboard issue and I don't want to write an actual ending:

The funny thing is that the whole reason I went down this rabbit hole of chasing this bug was because copying text didn't work in Micro, so I read the Micro source code, then read the zyedidia/clipboard library code that Micro was using, then the wl-clipboard source code since that's what zyedidia/clipboard internally uses, then read the xdg-mime source code. (The magic of open source!) Turns out the bug was much deeper than I originally expected, and nothing's wrong with wl-clipboard or Waypipe. 😃