From faa6736d29191bbaebee62f948e513a9755b7c06 Mon Sep 17 00:00:00 2001
From: Isaac Mills <rooster0055@protonmail.com>
Date: Fri, 30 May 2025 10:16:47 -0600
Subject: [PATCH] Add ability to configure atomic saving

---
 helix-core/src/editor_config.rs | 11 +++++++++++
 helix-view/src/document.rs      | 10 +++++++++-
 helix-view/src/editor.rs        |  3 +++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/helix-core/src/editor_config.rs b/helix-core/src/editor_config.rs
index 714f577c5..7515dd231 100644
--- a/helix-core/src/editor_config.rs
+++ b/helix-core/src/editor_config.rs
@@ -34,6 +34,7 @@ pub struct EditorConfig {
     // pub spelling_language: Option<SpellingLanguage>,
     pub trim_trailing_whitespace: Option<bool>,
     pub insert_final_newline: Option<bool>,
+    pub atomic_save: Option<bool>,
     pub max_line_length: Option<NonZeroU16>,
 }
 
@@ -159,6 +160,13 @@ impl EditorConfig {
                 "false" => Some(false),
                 _ => None,
             });
+        let atomic_save = pairs
+            .get("atomic_save")
+            .and_then(|value| match value.as_ref() {
+                "true" => Some(true),
+                "false" => Some(false),
+                _ => None,
+            });
         // This option is not in the spec but is supported by some editors.
         // <https://github.com/editorconfig/editorconfig/wiki/EditorConfig-Properties#max_line_length>
         let max_line_length = pairs
@@ -172,6 +180,7 @@ impl EditorConfig {
             encoding,
             trim_trailing_whitespace,
             insert_final_newline,
+            atomic_save,
             max_line_length,
         }
     }
@@ -305,6 +314,7 @@ mod test {
 
         [docs/**.txt]
         insert_final_newline = true
+        atomic_write = true
         "#;
 
         assert_eq!(
@@ -326,6 +336,7 @@ mod test {
             EditorConfig {
                 indent_style: Some(IndentStyle::Spaces(4)),
                 insert_final_newline: Some(true),
+                atomic_save: Some(true),
                 ..Default::default()
             }
         );
diff --git a/helix-view/src/document.rs b/helix-view/src/document.rs
index fb89e2e0c..458016492 100644
--- a/helix-view/src/document.rs
+++ b/helix-view/src/document.rs
@@ -980,6 +980,7 @@ impl Document {
         // mark changes up to now as saved
         let current_rev = self.get_current_revision();
         let doc_id = self.id();
+        let atomic_write = self.atomic_save();
 
         let encoding_with_bom_info = (self.encoding, self.has_bom);
         let last_saved_time = self.last_saved_time;
@@ -1029,7 +1030,7 @@ impl Document {
 
             // Assume it is a hardlink to prevent data loss if the metadata cant be read (e.g. on certain Windows configurations)
             let is_hardlink = helix_stdx::faccess::hardlink_count(&write_path).unwrap_or(2) > 1;
-            let backup = if path.exists() {
+            let backup = if path.exists() && atomic_write {
                 let path_ = write_path.clone();
                 // hacks: we use tempfile to handle the complex task of creating
                 // non clobbered temporary path for us we don't want
@@ -1914,6 +1915,13 @@ impl Document {
             .unwrap_or_else(|| self.config.load().insert_final_newline)
     }
 
+    /// Whether the document should write it's contents to a backup file, then rename the backup to the target file when saving. This prevents data loss when saving, but may confuse some file watching/hot reloading programs.
+    pub fn atomic_save(&self) -> bool {
+        self.editor_config
+            .atomic_save
+            .unwrap_or_else(|| self.config.load().atomic_save)
+    }
+
     /// Whether the document should trim whitespace preceding line endings on save.
     pub fn trim_trailing_whitespace(&self) -> bool {
         self.editor_config
diff --git a/helix-view/src/editor.rs b/helix-view/src/editor.rs
index bc811b88b..3a0b48d05 100644
--- a/helix-view/src/editor.rs
+++ b/helix-view/src/editor.rs
@@ -346,6 +346,8 @@ pub struct Config {
     pub default_line_ending: LineEndingConfig,
     /// Whether to automatically insert a trailing line-ending on write if missing. Defaults to `true`.
     pub insert_final_newline: bool,
+    /// Whether the document should write it's contents to a backup file, then rename the backup to the target file when saving. This prevents data loss when saving, but may confuse some file watching/hot reloading programs. Defaults to `true`
+    pub atomic_save: bool,
     /// Whether to automatically remove all trailing line-endings after the final one on write.
     /// Defaults to `false`.
     pub trim_final_newlines: bool,
@@ -1017,6 +1019,7 @@ impl Default for Config {
             workspace_lsp_roots: Vec::new(),
             default_line_ending: LineEndingConfig::default(),
             insert_final_newline: true,
+            atomic_save: true,
             trim_final_newlines: false,
             trim_trailing_whitespace: false,
             smart_tab: Some(SmartTabConfig::default()),