Failure to build on Emacs 30.2

[brittAnderson]

I get a failure trying to compile poly-R on nixos. Seems from the logs that that the specific error comes polymode when it needs poly-noweb to compile poly-R and uses define-keymap receiving ("<" . poly-noweb-electric-<) as a single cons cell argument rather than as two separate arguments. Hope this helps. Bit of a noob so if more or different details are needed please let me know.

[brittAnderson]

I was still having a problem compiling poly-r on nixos and my llm tells me the bug is actually in polymode. I don't understand the details and this is LLM generated (Opus 4.6), but maybe it will mean something to someone more expert.

Title: define-polymode fails on Emacs 30.2 with "Uneven number of key/definition pairs"
Environment: Emacs 30.2 (pgtk), polymode 20250502.1525 (from MELPA/nixpkgs), poly-R 20250502.1525, NixOS
Description:
Byte-compiling poly-R fails during the nixpkgs elpa2nix build phase with:
Error: error ("Uneven number of key/definition pairs")
error("Uneven number of key/definition pairs")
define-keymap(:parent (keymap (menu-bar keymap (polymode menu-item "Polymode" ...
The error originates in polymode's define-polymode macro, not in poly-R itself. Poly-R just triggers it via its define-polymode calls.
Root cause: Emacs 30 replaced easy-mmode-define-keymap internals with define-keymap, which strictly validates that key/definition pairs have even length. The keylist that define-polymode constructs from the parent polymode's keymap can produce an odd number of entries, which the old code tolerated but define-keymap rejects.
The backtrace shows define-keymap being called with :parent followed by the full parent keymap, suggesting the keylist flattening in define-polymode's keymap construction path is producing a malformed argument list under the new API.
This affects all polymodes derived from a parent (poly-R, poly-markdown, poly-noweb+r, etc.) on Emacs 30+.