feat: config: allow configuring which providers to use for diffs

book/src/configuration.md

@@ -397,3 +397,17 @@ S-tab = "move_parent_node_start"
 tab = "extend_parent_node_end"
 S-tab = "extend_parent_node_start"
 ```
+
+### `[editor.vcs]` Section
+
+Options for configuring VCSs (version control systems).
+
+| Key         | Description                                                                                                | Default  |
+| `providers` | VCSs to try (in the given order) for diff computations and the `version-control` element in the statusline | See note |
+
+The only valid provider is `git` at the moment (if Helix is compiled with git support)
+
+Note: the default providers change based on how Helix was compiled:
+
+- If the `git` feature was used (the default): `["git"]`
+- Else: `[]`

helix-vcs/Cargo.toml

@@ -22,6 +22,7 @@ arc-swap = { version = "1.7.0" }
 gix = { version = "0.58.0", features = ["attributes"], default-features = false, optional = true }
 imara-diff = "0.1.5"
 anyhow = "1"
+serde = { version = "1.0", features = ["derive"] }
 
 log = "0.4"
 

helix-vcs/src/config.rs

@@ -0,0 +1,37 @@
+//! Configuration for helix's VCS handling, to provide diffs and current VCS state.
+
+use serde::{Deserialize, Serialize};
+
+/// Main configuration struct, to be embedded in the larger editor configuration.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "kebab-case", default)]
+pub struct Vcs {
+    /// Providers for diff and state.
+    ///
+    /// The default is either the empty vec or just git (if the relevant feature is active).
+    #[serde(default = "default_providers")]
+    pub providers: Vec<Provider>,
+}
+
+impl Default for Vcs {
+    fn default() -> Self {
+        Self {
+            providers: default_providers(),
+        }
+    }
+}
+
+/// Supported providers
+#[derive(Debug, Copy, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+pub enum Provider {
+    #[cfg(feature = "git")]
+    Git,
+}
+
+fn default_providers() -> Vec<Provider> {
+    vec![
+        #[cfg(feature = "git")]
+        Provider::Git,
+    ]
+}

helix-vcs/src/git/test.rs

@@ -2,7 +2,7 @@ use std::{fs::File, io::Write, path::Path, process::Command};
 
 use tempfile::TempDir;
 
-use crate::{DiffProvider, Git};
+use crate::{git::Git, DiffProvider};
 
 fn exec_git_cmd(args: &str, git_dir: &Path) {
     let res = Command::new("git")

helix-vcs/src/lib.rs

@@ -1,19 +1,15 @@
-use anyhow::{bail, Result};
+use anyhow::Result;
 use arc_swap::ArcSwap;
 use std::{path::Path, sync::Arc};
 
-#[cfg(feature = "git")]
-pub use git::Git;
-#[cfg(not(feature = "git"))]
-pub use Dummy as Git;
-
 #[cfg(feature = "git")]
 mod git;
 
 mod diff;
-
 pub use diff::{DiffHandle, Hunk};
 
+pub mod config;
+
 pub trait DiffProvider {
     /// Returns the data that a diff should be computed against
     /// if this provider is used.
@@ -23,19 +19,8 @@ pub trait DiffProvider {
     fn get_current_head_name(&self, file: &Path) -> Result<Arc<ArcSwap<Box<str>>>>;
 }
 
-#[doc(hidden)]
-pub struct Dummy;
-impl DiffProvider for Dummy {
-    fn get_diff_base(&self, _file: &Path) -> Result<Vec<u8>> {
-        bail!("helix was compiled without git support")
-    }
-
-    fn get_current_head_name(&self, _file: &Path) -> Result<Arc<ArcSwap<Box<str>>>> {
-        bail!("helix was compiled without git support")
-    }
-}
-
 pub struct DiffProviderRegistry {
+    /// Built from the list in the user configuration.
     providers: Vec<Box<dyn DiffProvider>>,
 }
 
@@ -67,12 +52,17 @@ impl DiffProviderRegistry {
     }
 }
 
-impl Default for DiffProviderRegistry {
-    fn default() -> Self {
-        // currently only git is supported
-        // TODO make this configurable when more providers are added
-        let git: Box<dyn DiffProvider> = Box::new(Git);
-        let providers = vec![git];
-        DiffProviderRegistry { providers }
+impl From<&config::Vcs> for DiffProviderRegistry {
+    fn from(value: &config::Vcs) -> Self {
+        fn mapper(p: &config::Provider) -> Box<dyn DiffProvider> {
+            match p {
+                #[cfg(feature = "git")]
+                config::Provider::Git => Box::new(git::Git),
+            }
+        }
+
+        Self {
+            providers: value.providers.iter().map(mapper).collect(),
+        }
     }
 }

helix-view/src/editor.rs

@@ -305,6 +305,9 @@ pub struct Config {
     /// Which indent heuristic to use when a new line is inserted
     #[serde(default)]
     pub indent_heuristic: IndentationHeuristic,
+    /// VCS configuration (notably which to activate, in which order)
+    #[serde(default)]
+    pub vcs: helix_vcs::config::Vcs,
 }
 
 #[derive(Debug, Clone, PartialEq, Deserialize, Serialize, Eq, PartialOrd, Ord)]
@@ -867,6 +870,7 @@ impl Default for Config {
             smart_tab: Some(SmartTabConfig::default()),
             popup_border: PopupBorderConfig::None,
             indent_heuristic: IndentationHeuristic::default(),
+            vcs: Default::default(),
         }
     }
 }
@@ -1060,7 +1064,7 @@ impl Editor {
             theme: theme_loader.default(),
             language_servers,
             diagnostics: BTreeMap::new(),
-            diff_providers: DiffProviderRegistry::default(),
+            diff_providers: DiffProviderRegistry::from(&conf.vcs),
             debugger: None,
             debugger_events: SelectAll::new(),
             breakpoints: HashMap::new(),