From 244f2593314e6c83c2c890af6c5351fea0ec037b Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Mon, 16 Jan 2023 17:42:00 -0800
Subject: [PATCH] Always auto-indent in block-wise mode when pasting

If the text was copied outside of Zed, so the original indent column is unknown,
then act as if the first line was copied in its entirety.
---
 crates/editor/src/editor.rs   |  4 +++-
 crates/language/src/buffer.rs | 30 ++++++++++++++++--------------
 2 files changed, 19 insertions(+), 15 deletions(-)

diff --git a/crates/editor/src/editor.rs b/crates/editor/src/editor.rs
index 8847c01af7..fb8e37077e 100644
--- a/crates/editor/src/editor.rs
+++ b/crates/editor/src/editor.rs
@@ -2020,7 +2020,9 @@ impl Editor {
                     old_selections
                         .iter()
                         .map(|s| (s.start..s.end, text.clone())),
-                    Some(AutoindentMode::EachLine),
+                    Some(AutoindentMode::Block {
+                        original_indent_columns: Vec::new(),
+                    }),
                     cx,
                 );
                 anchors
diff --git a/crates/language/src/buffer.rs b/crates/language/src/buffer.rs
index 9ceb6b32a9..d1e7316f1b 100644
--- a/crates/language/src/buffer.rs
+++ b/crates/language/src/buffer.rs
@@ -1332,13 +1332,6 @@ impl Buffer {
         let edit_id = edit_operation.local_timestamp();
 
         if let Some((before_edit, mode)) = autoindent_request {
-            let (start_columns, is_block_mode) = match mode {
-                AutoindentMode::Block {
-                    original_indent_columns: start_columns,
-                } => (start_columns, true),
-                AutoindentMode::EachLine => (Default::default(), false),
-            };
-
             let mut delta = 0isize;
             let entries = edits
                 .into_iter()
@@ -1352,7 +1345,7 @@ impl Buffer {
 
                     let mut range_of_insertion_to_indent = 0..new_text_len;
                     let mut first_line_is_new = false;
-                    let mut start_column = None;
+                    let mut original_indent_column = None;
 
                     // When inserting an entire line at the beginning of an existing line,
                     // treat the insertion as new.
@@ -1364,14 +1357,23 @@ impl Buffer {
 
                     // When inserting text starting with a newline, avoid auto-indenting the
                     // previous line.
-                    if new_text[range_of_insertion_to_indent.clone()].starts_with('\n') {
+                    if new_text.starts_with('\n') {
                         range_of_insertion_to_indent.start += 1;
                         first_line_is_new = true;
                     }
 
                     // Avoid auto-indenting after the insertion.
-                    if is_block_mode {
-                        start_column = start_columns.get(ix).copied();
+                    if let AutoindentMode::Block {
+                        original_indent_columns,
+                    } = &mode
+                    {
+                        original_indent_column =
+                            Some(original_indent_columns.get(ix).copied().unwrap_or_else(|| {
+                                indent_size_for_text(
+                                    new_text[range_of_insertion_to_indent.clone()].chars(),
+                                )
+                                .len
+                            }));
                         if new_text[range_of_insertion_to_indent.clone()].ends_with('\n') {
                             range_of_insertion_to_indent.end -= 1;
                         }
@@ -1379,7 +1381,7 @@ impl Buffer {
 
                     AutoindentRequestEntry {
                         first_line_is_new,
-                        original_indent_column: start_column,
+                        original_indent_column,
                         indent_size: before_edit.language_indent_size_at(range.start, cx),
                         range: self.anchor_before(new_start + range_of_insertion_to_indent.start)
                             ..self.anchor_after(new_start + range_of_insertion_to_indent.end),
@@ -1390,7 +1392,7 @@ impl Buffer {
             self.autoindent_requests.push(Arc::new(AutoindentRequest {
                 before_edit,
                 entries,
-                is_block_mode,
+                is_block_mode: matches!(mode, AutoindentMode::Block { .. }),
             }));
         }
 
@@ -2397,7 +2399,7 @@ impl BufferSnapshot {
     }
 }
 
-pub fn indent_size_for_line(text: &text::BufferSnapshot, row: u32) -> IndentSize {
+fn indent_size_for_line(text: &text::BufferSnapshot, row: u32) -> IndentSize {
     indent_size_for_text(text.chars_at(Point::new(row, 0)))
 }