tmux: add proposed upstream fix for split-window regression

[alois31]

In tmux 3.4, a regression was introduced that breaks the deprecated (but still supported for backwards compatibility) -p option to split-window. Several external tools (for example fzf.kak, fzf-tmux and nnn) break due to this. Add the proposed upstream fix from tmux/tmux#3840.

Description of changes

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.05 Release Notes (or backporting 23.05 and 23.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

---

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[x10an14]

If this way of testing is equivalent/accepted, then yes, this works for me on 1xx86_64-linux NixOS (the config change/patch was introduced through home-manager).

diff --git a/home-manager/programs/terminal/tmux.nix b/home-manager/programs/terminal/tmux.nix
index aae6d8f..46836cf 100644
--- a/home-manager/programs/terminal/tmux.nix
+++ b/home-manager/programs/terminal/tmux.nix
@@ -53,4 +53,23 @@ in {
       '')
     ];
   };
+  nixpkgs.overlays = [
+    (final: prev: {
+      tmux = prev.tmux.overrideAttrs (old: {
+        patches =
+          (old.patches or [])
+          ++ [
+            (
+              # For context, see:
+              # https://github.com/NixOS/nixpkgs/pull/289789/files
+              # TODO: Remove when fixed
+              pkgs.fetchpatch {
+                url = "https://github.com/tmux/tmux/commit/2d1afa0e62a24aa7c53ce4fb6f1e35e29d01a904.diff";
+                hash = "sha256-mDt5wy570qrUc0clGa3GhZFTKgL0sfnQcWJEJBKAbKs=";
+              }
+            )
+          ];
+      });
+    })
+  ];
 }

EDIT: Formatting

[otavio]

I can confirm that this solution worked for me as well, resolving the issue.

[x10an14]

Are we certain we wanted to merge this? What mechanism is in place for this not just breaking once the tmux package gets upgraded in nixpkgs next time?

We trust in the people performing the upgrade testing the software before pushing PR?