Overhauling Zellij's Resize & Layout System

[TheLostLambda]

Should close #619 and #406 when merged :)

[imsnif]

Hey @TheLostLambda
Great work so far. This is definitely a tremendous effort! I think it would be great both for the functionality and for the code base once this is merged.

I took this for a spin and found some issues:

1. When resizing the terminal window to a very small width, there's a hard crash:

        Error occured in server:
        Originating Thread(s):
        1. screen_thread: TerminalResize
        2. plugin_thread: Render

        Error: thread 'wasm' panicked at 'called `Result::unwrap()` on an `Err` value: RuntimeError { source: Trap(UnreachableCodeReached), wasm_trace: [FrameInfo { module_name: "<module>", func_index: 1663, function_name: Some("__rust_start_panic"), func_start: SourceLoc(501416), instr: SourceLoc(501417) }, FrameInfo { module_name: "<module>", func_index: 1656, function_name: Some("rust_panic"), func_start: SourceLoc(500444), instr: SourceLoc(500483) }, FrameInfo { module_name: "<module>", func_index: 1649, function_name: Some("_ZN3std9panicking20rust_panic_with_hook17h308937c11f14a0b0E"), func_start: SourceLoc(498376), instr: SourceLoc(499568) }, FrameInfo { module_name: "<module>", func_index: 1637, function_name: Some("_ZN3std9panicking19begin_panic_handler28_$u7b$$u7b$closure$u7d$$u7d$17h2f1ffd2e7af6e54eE"), func_start: SourceLoc(496583), instr: SourceLoc(496718) }, FrameInfo { module_name: "<module>", func_index: 1636, function_name: Some("_ZN3std10sys_common9backtrace26__rust_end_short_backtrace17h0391a3209a34137cE"), func_start: SourceLoc(496525), instr: SourceLoc(496573) }, FrameInfo { module_name: "<module>", func_index: 1648, function_name: Some("rust_begin_unwind"), func_start: SourceLoc(498285), instr: SourceLoc(498366) }, FrameInfo { module_name: "<module>", func_index: 1736, function_name: Some("_ZN4core9panicking9panic_fmt17hf6b8f38d129daac6E"), func_start: SourceLoc(537720), instr: SourceLoc(537778) }, FrameInfo { module_name: "<module>", func_index: 1719, function_name: Some("_ZN4core9panicking5panic17haa6b780f40788db6E"), func_start: SourceLoc(520019), instr: SourceLoc(520095) }, FrameInfo { module_name: "<module>", func_index: 571, function_name: Some("_ZN7tab_bar4line15tab_line_prefix17h9264f28801c06ad0E"), func_start: SourceLoc(243619), instr: SourceLoc(246448) }, FrameInfo { module_name: "<module>", func_index: 573, function_name: Some("_ZN7tab_bar4line8tab_line17h4e89bbaeb373a6d2E"), func_start: SourceLoc(247211), instr: SourceLoc(247963) }, FrameInfo { module_name: "<module>", func_index: 427, function_name: Some("_ZN60_$LT$tab_bar..State$u20$as$u20$zellij_tile..ZellijPlugin$GT$6render17h3cc8604a9333131dE"), func_start: SourceLoc(206451), instr: SourceLoc(207828) }, FrameInfo { module_name: "<module>", func_index: 73, function_name: Some("_ZN7tab_bar6render28_$u7b$$u7b$closure$u7d$$u7d$17h33c27749257b30aeE"), func_start: SourceLoc(12904), instr: SourceLoc(13048) }, FrameInfo { module_name: "<module>", func_index: 122, function_name: Some("_ZN3std6thread5local17LocalKey$LT$T$GT$8try_with17h97d8310b9e1654bbE"), func_start: SourceLoc(20530), instr: SourceLoc(20695) }, FrameInfo { module_name: "<module>", func_index: 121, function_name: Some("_ZN3std6thread5local17LocalKey$LT$T$GT$4with17hba3182caed98ee8dE"), func_start: SourceLoc(20388), instr: SourceLoc(20445) }, FrameInfo { module_name: "<module>", func_index: 431, function_name: Some("render"), func_start: SourceLoc(211413), instr: SourceLoc(211522) }, FrameInfo { module_name: "<module>", func_index: 1824, function_name: Some("render.command_export"), func_start: SourceLoc(560686), instr: SourceLoc(560693) }], native_trace:    0: <unknown>
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         }': zellij-server/src/wasm_vm.rs:145
           0: zellij_utils::errors::handle_panic
                     at zellij-utils/src/errors.rs:24:21
           1: zellij_server::start_server::{{closure}}
                     at zellij-server/src/lib.rs:137:13
           2: std::panicking::rust_panic_with_hook
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:626:17
           3: std::panicking::begin_panic_handler::{{closure}}
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:519:13
           4: std::sys_common::backtrace::__rust_end_short_backtrace
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/sys_common/backtrace.rs:141:18
           5: rust_begin_unwind
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:515:5
           6: core::panicking::panic_fmt
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/panicking.rs:92:14
           7: core::result::unwrap_failed
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/result.rs:1355:5
           8: core::result::Result<T,E>::unwrap
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/result.rs:1037:23
           9: zellij_server::wasm_vm::wasm_thread_main
                     at zellij-server/src/wasm_vm.rs:143:21
          10: zellij_server::init_session::{{closure}}
                     at zellij-server/src/lib.rs:388:21
          11: std::sys_common::backtrace::__rust_begin_short_backtrace
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/sys_common/backtrace.rs:125:18
          12: std::thread::Builder::spawn_unchecked::{{closure}}::{{closure}}
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/thread/mod.rs:481:17
          13: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panic.rs:347:9
          14: std::panicking::try::do_call
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:401:40
          15: __rust_try
          16: std::panicking::try
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panicking.rs:365:19
          17: std::panic::catch_unwind
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/panic.rs:434:14
          18: std::thread::Builder::spawn_unchecked::{{closure}}
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/thread/mod.rs:480:30
          19: core::ops::function::FnOnce::call_once{{vtable.shim}}
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/core/src/ops/function.rs:227:5
          20: <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/alloc/src/boxed.rs:1575:9
              <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/alloc/src/boxed.rs:1575:9
              std::sys::unix::thread::Thread::new::thread_start
                     at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/sys/unix/thread.rs:71:17
          21: start_thread
          22: __GI___clone

2. When resizing the terminal panes themselves, there are glitches and jumps. Here's a video example of a relatively simple case (it happens in other cases as well):

resize-bug.mp4

3. When splitting down twice, the new pane overlaps. Again, this happened in other places too but this is the most basic example I could find:

split-down-bug.mp4

4. Also, it seems to me like one can resize terminals below their minimum height... maybe this is related to some of the other issues?

[TheLostLambda]

Hi @imsnif ! Some good finds!

Sorry for leaving that mess for you to look at, I introduced bugs 2 and 3 in the refactoring commit ee3eb2a after I'd done all of my testing! I'll have an updated (refactored and fixed) version today!

1 should just be an easy fix in the tab-bar code.

What do you mean in 4? Do they become smaller than the minimum when resizing the whole terminal or can you split things with a fixed-size window and get that effect?

Thanks again for giving this a look and sorry I busted things during my refactor!

[a-kenji]

@TheLostLambda,
This looks great, I have tried various resizes and everything
works flawlessly - even while toggling tiling/floating/fullscreen.

[TheLostLambda]

@a-kenji
Thanks for giving things a test! I'm just re-adding a couple of unit tests that I lost early on in the refactor process, but I've done quite a bit of testing as well and am planning on merging things tonight!

I'm excited to have all of this work in main!

[TheLostLambda]

Merge delayed until tomorrow because I just so happened to delete the biggest set of tests in the repo 😅

I'm fixing them up (mostly fixing the tests themselves) and should finish soonish :)