From 70cb2fa8d73ab0b2ccdcd5ba5b01f1c45aafd8ec Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Wed, 1 Mar 2023 10:17:04 -0800
Subject: [PATCH] Apply external command formatting if buffer has changed while
 computing it

---
 crates/language/src/buffer.rs       | 46 ++++++++++-------------------
 crates/language/src/buffer_tests.rs |  2 +-
 crates/project/src/project.rs       |  2 +-
 3 files changed, 18 insertions(+), 32 deletions(-)

diff --git a/crates/language/src/buffer.rs b/crates/language/src/buffer.rs
index 5d7e4325d15af8f59af549bb4253b428d68fbc39..acccb553d3d14d11e6140fb8e2a81818214e84e1 100644
--- a/crates/language/src/buffer.rs
+++ b/crates/language/src/buffer.rs
@@ -569,20 +569,21 @@ impl Buffer {
                     .read_with(&cx, |this, cx| this.diff(new_text, cx))
                     .await;
                 this.update(&mut cx, |this, cx| {
-                    this.finalize_last_transaction();
-                    this.apply_diff(diff, cx);
-                    if let Some(transaction) = this.finalize_last_transaction().cloned() {
-                        this.did_reload(
-                            this.version(),
-                            this.as_rope().fingerprint(),
-                            this.line_ending(),
-                            new_mtime,
-                            cx,
-                        );
-                        Ok(Some(transaction))
-                    } else {
-                        Ok(None)
+                    if this.version() == diff.base_version {
+                        this.finalize_last_transaction();
+                        this.apply_diff(diff, cx);
+                        if let Some(transaction) = this.finalize_last_transaction().cloned() {
+                            this.did_reload(
+                                this.version(),
+                                this.as_rope().fingerprint(),
+                                this.line_ending(),
+                                new_mtime,
+                                cx,
+                            );
+                            return Ok(Some(transaction));
+                        }
                     }
+                    Ok(None)
                 })
             } else {
                 Ok(None)
@@ -1197,25 +1198,10 @@ impl Buffer {
         self.edit([(offset..len, "\n")], None, cx);
     }
 
-    pub fn apply_diff(&mut self, diff: Diff, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
-        if self.version == diff.base_version {
-            self.start_transaction();
-            self.text.set_line_ending(diff.line_ending);
-            self.edit(diff.edits, None, cx);
-            self.end_transaction(cx)
-        } else {
-            return None;
-        }
-    }
-
     /// Apply a diff to the buffer. If the buffer has changed since the given diff was
     /// calculated, then adjust the diff to account for those changes, and discard any
     /// parts of the diff that conflict with those changes.
-    pub fn apply_non_conflicting_portion_of_diff(
-        &mut self,
-        diff: Diff,
-        cx: &mut ModelContext<Self>,
-    ) -> Option<TransactionId> {
+    pub fn apply_diff(&mut self, diff: Diff, cx: &mut ModelContext<Self>) -> Option<TransactionId> {
         // Check for any edits to the buffer that have occurred since this diff
         // was computed.
         let snapshot = self.snapshot();
@@ -1223,7 +1209,7 @@ impl Buffer {
         let mut delta = 0;
         let adjusted_edits = diff.edits.into_iter().filter_map(|(range, new_text)| {
             while let Some(edit_since) = edits_since.peek() {
-                // If the edit occurs after a diff hunk, then it can does not
+                // If the edit occurs after a diff hunk, then it does not
                 // affect that hunk.
                 if edit_since.old.start > range.end {
                     break;
diff --git a/crates/language/src/buffer_tests.rs b/crates/language/src/buffer_tests.rs
index c7fc25d793ac0d16d4904a504c38181545775fa4..0c375f0f4e1e27e59bbc737443307ae1b9c94c66 100644
--- a/crates/language/src/buffer_tests.rs
+++ b/crates/language/src/buffer_tests.rs
@@ -254,7 +254,7 @@ async fn test_normalize_whitespace(cx: &mut gpui::TestAppContext) {
     let format_diff = format.await;
     buffer.update(cx, |buffer, cx| {
         let version_before_format = format_diff.base_version.clone();
-        buffer.apply_non_conflicting_portion_of_diff(format_diff, cx);
+        buffer.apply_diff(format_diff, cx);
 
         // The outcome depends on the order of concurrent taks.
         //
diff --git a/crates/project/src/project.rs b/crates/project/src/project.rs
index cadbde0bac9a5bbc8f05b6966e0e6c9d8d492766..0325d07ce6a38991b31f27ff31895c6d4cb0061a 100644
--- a/crates/project/src/project.rs
+++ b/crates/project/src/project.rs
@@ -2921,7 +2921,7 @@ impl Project {
                         buffer.finalize_last_transaction();
                         buffer.start_transaction();
                         if let Some(diff) = trailing_whitespace_diff {
-                            buffer.apply_non_conflicting_portion_of_diff(diff, cx);
+                            buffer.apply_diff(diff, cx);
                         }
                         if ensure_final_newline {
                             buffer.ensure_final_newline(cx);