From 32013b13e359ef55b57ff2a005b9bdc52e9692dc Mon Sep 17 00:00:00 2001
From: Sylvain Terrien <sylvain.terrien@protonmail.com>
Date: Mon, 23 Jun 2025 01:03:22 +0200
Subject: [PATCH] fix: alignment when indenting with spaces (#13498)

Adjust the number of spaces inserted, so that indentation is aligned
on columns.
---
 helix-term/src/commands.rs                 | 31 +++++++++---
 helix-term/tests/test/commands/insert.rs   | 56 ++++++++++++++++++++++
 helix-term/tests/test/commands/movement.rs |  2 +-
 3 files changed, 81 insertions(+), 8 deletions(-)

diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 38e52e18c..119470239 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -4174,14 +4174,22 @@ pub mod insert {
 
     pub fn insert_tab(cx: &mut Context) {
         let (view, doc) = current!(cx.editor);
-        // TODO: round out to nearest indentation level (for example a line with 3 spaces should
-        // indent by one to reach 4 spaces).
 
-        let indent = Tendril::from(doc.indent_style.as_str());
-        let transaction = Transaction::insert(
+        let transaction = Transaction::change(
             doc.text(),
-            &doc.selection(view.id).clone().cursors(doc.text().slice(..)),
-            indent,
+            doc.selection(view.id).ranges().iter().map(|range| {
+                let indent = if let IndentStyle::Spaces(indent_width) = doc.indent_style {
+                    let line = range.cursor_line(doc.text().slice(..));
+                    let line_start = doc.text().line_to_char(line);
+                    let offset = (range.head - line_start) % indent_width as usize;
+
+                    Tendril::from(doc.indent_style.as_str()).split_off(offset)
+                } else {
+                    Tendril::from(doc.indent_style.as_str())
+                };
+
+                (range.head, range.head, Some(indent))
+            }),
         );
         doc.apply(&transaction, view.id);
     }
@@ -4867,7 +4875,16 @@ fn indent(cx: &mut Context) {
                 return None;
             }
             let pos = doc.text().line_to_char(line);
-            Some((pos, pos, Some(indent.clone())))
+
+            let indent = if let IndentStyle::Spaces(indent_width) = doc.indent_style {
+                let line = doc.text().line(line);
+                let offset = line.first_non_whitespace_char().unwrap_or(0) % indent_width as usize;
+                indent.clone().split_off(offset)
+            } else {
+                indent.clone()
+            };
+
+            Some((pos, pos, Some(indent)))
         }),
     );
     doc.apply(&transaction, view.id);
diff --git a/helix-term/tests/test/commands/insert.rs b/helix-term/tests/test/commands/insert.rs
index 9499868e2..7f00826bb 100644
--- a/helix-term/tests/test/commands/insert.rs
+++ b/helix-term/tests/test/commands/insert.rs
@@ -583,3 +583,59 @@ async fn test_jump_undo_redo() -> anyhow::Result<()> {
     .await?;
     Ok(())
 }
+
+#[tokio::test(flavor = "multi_thread")]
+async fn test_indent_with_spaces() -> anyhow::Result<()> {
+    let tests = vec![
+        // at start of line
+        (
+            indoc! {"\
+                SELECT *
+                  #[|FROM table]#
+                 #(|WHERE condition)#
+            "},
+            "i<tab>",
+            indoc! {"\
+                SELECT *
+                    #[|FROM table]#
+                    #(|WHERE condition)#
+            "},
+        ),
+        // in the middle of line
+        (
+            indoc! {"\
+                SELECT #[*|]#
+                FROM #(table|)#
+                WHERE #(condition|)#
+            "},
+            "i<S-tab>",
+            indoc! {"\
+                SELECT  #[|*]#
+                FROM    #(|table)#
+                WHERE   #(|condition)#
+            "},
+        ),
+        // indentation in normal mode
+        (
+            indoc! {"\
+                -- comment
+                #[|SELECT *
+                  FROM table
+                 WHERE condition]#
+            "},
+            "<gt>",
+            indoc! {"\
+                -- comment
+                    #[|SELECT *
+                    FROM table
+                    WHERE condition]#
+            "},
+        ),
+    ];
+
+    for test in tests {
+        test_with_config(AppBuilder::new().with_file("foo.rs", None), test).await?;
+    }
+
+    Ok(())
+}
diff --git a/helix-term/tests/test/commands/movement.rs b/helix-term/tests/test/commands/movement.rs
index 5868fa494..c7e71ae92 100644
--- a/helix-term/tests/test/commands/movement.rs
+++ b/helix-term/tests/test/commands/movement.rs
@@ -437,7 +437,7 @@ async fn test_smart_tab_move_parent_node_end() -> anyhow::Result<()> {
                     let result = if true {
                             #[|\"yes\"\n]#
                     } else {
-                        \"no    #(|\"\n)#
+                        \"no #(|\"\n)#
                     }
                 }
             "},