bug#65113: Emacs-29 and master csharp-mode with broken treesit

[J M <jean@tbm.email>]

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Hi Eli

See attached the requested backward-compatible change.


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From ca9ad7d0738e71775bdc1d83f7aa5a2849ba5a8b Mon Sep 17 00:00:00 2001
From: J M <jean@tbm.email>
Date: Thu, 10 Aug 2023 23:23:20 +0100
Subject: [PATCH] Update csharp treesit support due to upstream changes
 (bug#65113)

A change in tree-sitter-c-sharp grammar for csharp (commit
18a531), has removed the keyword void_keyword and advised
we should use predefined_type
---
 lisp/progmodes/csharp-mode.el | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lisp/progmodes/csharp-mode.el b/lisp/progmodes/csharp-mode.el
index 00587a8a515..74968f3a06a 100644
--- a/lisp/progmodes/csharp-mode.el
+++ b/lisp/progmodes/csharp-mode.el
@@ -816,7 +816,7 @@ csharp-ts-mode--font-lock-settings
    :language 'c-sharp
    :feature 'definition
    :override t
-   '((qualified_name (identifier) @font-lock-type-face)
+   `((qualified_name (identifier) @font-lock-type-face)
      (using_directive (identifier) @font-lock-type-face)
      (using_directive (name_equals
                        (identifier) @font-lock-type-face))
@@ -843,8 +843,13 @@ csharp-ts-mode--font-lock-settings
      (class_declaration (identifier) @font-lock-type-face)
 
      (constructor_declaration name: (_) @font-lock-type-face)
-
-     (method_declaration type: [(identifier) (void_keyword)] @font-lock-type-face)
+     ;;; Handle different releases of tree-sitter-c-sharp.
+     ;;; Check if keyword void_keyword is available, then return the correct rule."
+     ,@(condition-case nil
+           (progn (treesit-query-capture 'csharp '((void_keyword) @capture))
+                  `((method_declaration type: [(identifier) (void_keyword)] @font-lock-type-face)))
+         (error
+          `((method_declaration type: [(identifier) (predefined_type)] @font-lock-type-face))))
      (method_declaration type: (generic_name (identifier) @font-lock-type-face))
      (method_declaration name: (_) @font-lock-function-name-face)
 
-- 


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> On 10 Aug 2023, at 10:05, Eli Zaretskii <eliz@gnu.org> wrote:
> 
>> Date: Mon, 07 Aug 2023 07:46:05 +0200
>> From: Theodor Thornhill <theo@thornhill.no>
>> CC: 65113@debbugs.gnu.org
> 
> Ping!  Can we please have a patch that is backward-compatible?
> 
>> On 6 August 2023 17:36:47 CEST, Eli Zaretskii <eliz@gnu.org> wrote:
>>>> From: J M <jean@tbm.email>
>>>> Date: Sun, 6 Aug 2023 16:03:45 +0100
>>>> 
>>>> Treesit is broken for csharp-mode in the latest version in master and emacs-29 and therefore does not provide syntax highlighting. 
>>>> 
>>>> The latest grammar repository (https://github.com/tree-sitter/tree-sitter-c-sharp) has removed the keyword void_keyword.
>>>> 
>>>> Please see attached the patch to resolve the issue.
>>> 
>>> Thanks, but your patch will not work with the older version of the
>>> grammar library, right?  Is it possible to make a patch that will work
>>> with both?  Wed cannot rely on users having the latest grammar
>>> versions, so a backward-compatible change is much more preferable.
>> 
>> We've had some similar patches lately that you can use for inspiration.
>> 
>> Thanks,
>> Theo
>>