Rework shared commit editors (#24274)

Rework of https://github.com/zed-industries/zed/pull/24130
Uses
1033c0b57e
`COMMIT_EDITMSG` language-related definitions (thanks @d1y )

Instead of using real `.git/COMMIT_EDITMSG` file, create a buffer
without FS representation, stored in the `Repository` and shared the
regular way via the `BufferStore`.
Adds a knowledge of what `Git Commit` language is, and uses it in the
buffers which are rendered in the git panel.


Release Notes:

- N/A

---------

Co-authored-by: Conrad Irwin <conrad@zed.dev>
Co-authored-by: d1y <chenhonzhou@gmail.com>
Co-authored-by: Smit <smit@zed.dev>

crates/languages/Cargo.toml

@@ -19,6 +19,7 @@ load-grammars = [
     "tree-sitter-cpp",
     "tree-sitter-css",
     "tree-sitter-diff",
+    "tree-sitter-gitcommit",
     "tree-sitter-go",
     "tree-sitter-go-mod",
     "tree-sitter-gowork",
@@ -69,6 +70,7 @@ tree-sitter-c = { workspace = true, optional = true }
 tree-sitter-cpp = { workspace = true, optional = true }
 tree-sitter-css = { workspace = true, optional = true }
 tree-sitter-diff = { workspace = true, optional = true }
+tree-sitter-gitcommit = {workspace = true, optional = true }
 tree-sitter-go = { workspace = true, optional = true }
 tree-sitter-go-mod = { workspace = true, optional = true }
 tree-sitter-gowork = { workspace = true, optional = true }

crates/languages/src/gitcommit/config.toml

@@ -0,0 +1,18 @@
+name = "Git Commit"
+grammar = "git_commit"
+path_suffixes = [
+  "TAG_EDITMSG",
+  "MERGE_MSG",
+  "COMMIT_EDITMSG",
+  "NOTES_EDITMSG",
+  "EDIT_DESCRIPTION",
+]
+line_comments = ["#"]
+brackets = [
+  { start = "(", end = ")", close = true, newline = false },
+  { start = "`", end = "`", close = true, newline = false },
+  { start = "\"", end = "\"", close = true, newline = false },
+  { start = "'", end = "'", close = true, newline = false },
+  { start = "{", end = "}", close = true, newline = false },
+  { start = "[", end = "]", close = true, newline = false },
+]

crates/languages/src/gitcommit/highlights.scm

@@ -0,0 +1,18 @@
+(subject) @markup.heading
+(path) @string.special.path
+(branch) @string.special.symbol
+(commit) @constant
+(item) @markup.link.url
+(header) @tag
+
+(change kind: "new file" @diff.plus)
+(change kind: "deleted" @diff.minus)
+(change kind: "modified" @diff.delta)
+(change kind: "renamed" @diff.delta.moved)
+
+(trailer
+  key: (trailer_key) @variable.other.member
+  value: (trailer_value) @string)
+
+[":" "=" "->" (scissors)] @punctuation.delimiter
+(comment) @comment

crates/languages/src/gitcommit/injections.scm

@@ -0,0 +1,5 @@
+((scissors) @content
+ (#set! "language" "diff"))
+
+((rebase_command) @content
+ (#set! "language" "git_rebase"))

crates/languages/src/lib.rs

@@ -31,6 +31,25 @@ mod yaml;
 #[exclude = "*.rs"]
 struct LanguageDir;
 
+/// A shared grammar for plain text, exposed for reuse by downstream crates.
+#[cfg(feature = "tree-sitter-gitcommit")]
+pub static LANGUAGE_GIT_COMMIT: std::sync::LazyLock<Arc<Language>> =
+    std::sync::LazyLock::new(|| {
+        Arc::new(Language::new(
+            LanguageConfig {
+                name: "Git Commit".into(),
+                soft_wrap: Some(language::language_settings::SoftWrap::EditorWidth),
+                matcher: LanguageMatcher {
+                    path_suffixes: vec!["COMMIT_EDITMSG".to_owned()],
+                    first_line_pattern: None,
+                },
+                line_comments: vec![Arc::from("#")],
+                ..LanguageConfig::default()
+            },
+            Some(tree_sitter_gitcommit::LANGUAGE.into()),
+        ))
+    });
+
 pub fn init(languages: Arc<LanguageRegistry>, node_runtime: NodeRuntime, cx: &mut App) {
     #[cfg(feature = "load-grammars")]
     languages.register_native_grammars([
@@ -53,6 +72,7 @@ pub fn init(languages: Arc<LanguageRegistry>, node_runtime: NodeRuntime, cx: &mu
         ("tsx", tree_sitter_typescript::LANGUAGE_TSX),
         ("typescript", tree_sitter_typescript::LANGUAGE_TYPESCRIPT),
         ("yaml", tree_sitter_yaml::LANGUAGE),
+        ("gitcommit", tree_sitter_gitcommit::LANGUAGE),
     ]);
 
     macro_rules! language {