From 8ced80fb2dd58742219205032dc8d74e35ec029c Mon Sep 17 00:00:00 2001
From: Xi Xiao <xi.xiao007@gmail.com>
Date: Fri, 14 Mar 2025 08:17:43 +0200
Subject: [PATCH] chore: better way to fix `else` idempotent issue

---
 src/context.rs    |  9 --------
 src/data_model.rs | 59 +++++++++++++++++++++++++----------------------
 src/utility.rs    |  6 -----
 3 files changed, 32 insertions(+), 42 deletions(-)

diff --git a/src/context.rs b/src/context.rs
index b698a41d..5040d196 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -114,10 +114,6 @@ impl Comment {
         self.metadata.has_empty_line_above
     }
 
-    pub fn has_prev_node_else_keyword(&self) -> bool {
-        self.metadata.has_prev_node_else_keyword
-    }
-
     pub fn is_followed_by_bracket_composite_node(&self) -> bool {
         self.metadata.is_followed_by_bracket_composite_node
     }
@@ -167,7 +163,6 @@ pub struct CommentMetadata {
     has_empty_line_above: bool,
     has_empty_line_below: bool,
     has_prev_node: bool,
-    has_prev_node_else_keyword: bool,
     is_followed_by_bracket_composite_node: bool,
 }
 
@@ -176,9 +171,6 @@ impl CommentMetadata {
         let prev = node.prev_named_sibling();
         let has_prev_node = prev.is_some();
 
-        let prev_unnamed = node.prev_sibling();
-        let has_prev_node_else_keyword = prev_unnamed.map(|n| n.kind() == "else").unwrap_or(false);
-
         let has_leading_content = if let Some(prev_node) = prev {
             node.start_position().row == prev_node.end_position().row
         } else {
@@ -221,7 +213,6 @@ impl CommentMetadata {
             has_empty_line_above,
             has_empty_line_below,
             has_prev_node,
-            has_prev_node_else_keyword,
             is_followed_by_bracket_composite_node,
         }
     }
diff --git a/src/data_model.rs b/src/data_model.rs
index f3bf1c33..6fd66345 100644
--- a/src/data_model.rs
+++ b/src/data_model.rs
@@ -1317,6 +1317,7 @@ pub struct IfStatement {
     pub consequence: Statement,
     pub alternative: Option<Statement>,
     pub node_context: NodeContext,
+    pub has_else_and_followed_by_new_line_comment: bool, // https://github.com/xixiaofinland/afmt/issues/67
 }
 
 impl IfStatement {
@@ -1325,10 +1326,23 @@ impl IfStatement {
 
         let alternative = node.try_c_by_n("alternative").map(|a| Statement::new(a));
 
+        let has_else_and_followed_by_new_line_comment = alternative.is_some()
+            && node
+                .children(&mut node.walk())
+                .find(|n| n.kind() == "else")
+                .and_then(|else_node| {
+                    else_node.next_sibling().map(|next_sibling| {
+                        next_sibling.is_extra()
+                            && next_sibling.start_position().row != else_node.end_position().row
+                    })
+                })
+                .unwrap_or(false);
+
         Self {
             condition: ParenthesizedExpression::new(node.c_by_n("condition")),
             consequence: Statement::new(node.c_by_n("consequence")),
             alternative,
+            has_else_and_followed_by_new_line_comment,
             node_context: NodeContext::with_punctuation(&node),
         }
     }
@@ -1350,37 +1364,28 @@ impl<'a> DocBuild<'a> for IfStatement {
 
             // Handle the 'else' part
             if let Some(ref a) = self.alternative {
-                match a {
-                    Statement::If(_) => {
-                        if self.consequence.is_block() {
-                            result.push(b.txt(" else "));
-                        } else {
-                            result.push(b.nl());
-                            result.push(b.txt("else "));
-                        }
-                        result.push(a.build(b)); // Recursively build the nested 'else if' statement
+                if self.consequence.is_block() {
+                    result.push(b.txt(" else"));
+                    if self.has_else_and_followed_by_new_line_comment {
+                        result.push(b.nl());
+                    } else {
+                        result.push(b.txt(" "));
                     }
-                    Statement::Block(_) => {
-                        if self.consequence.is_block() {
-                            result.push(b.txt(" else "));
-                        } else {
-                            result.push(b.nl());
-                            result.push(b.txt("else "));
-                        }
-                        result.push(a.build(b));
+                } else {
+                    result.push(b.nl());
+                    result.push(b.txt("else"));
+                    if self.has_else_and_followed_by_new_line_comment {
+                        result.push(b.nl());
                     }
-                    // Handle "else" with a single statement
-                    _ => {
-                        if self.consequence.is_block() {
-                            result.push(b.txt(" else "));
-                        } else {
-                            result.push(b.nl());
-                            result.push(b.txt("else"));
-                            result.push(b.indent(b.nl()));
-                        }
-                        result.push(a.build(b)); // Build the else statement
+
+                    if !matches!(a, Statement::If(_) | Statement::Block(_)) {
+                        result.push(b.indent(b.nl()));
+                    } else {
+                        result.push(b.txt(" "));
                     }
                 }
+
+                result.push(a.build(b));
             }
         });
     }
diff --git a/src/utility.rs b/src/utility.rs
index dc08b324..629f3857 100644
--- a/src/utility.rs
+++ b/src/utility.rs
@@ -355,15 +355,9 @@ pub fn handle_pre_comments<'a>(
             docs.push(b.txt(" "));
         } else {
             // if it's in group(), then multi-line mode is selected in fits()
-            // otherwise, do nothing
             docs.push(b.force_break());
 
             // 1st element heading logic is handled in the preceding node;
-            // except the preceding is an unnamed node like `else`
-            if comment.has_prev_node_else_keyword() {
-                docs.push(b.nl());
-            }
-
             if i != 0 {
                 if comment.has_newline_above() {
                     docs.push(b.empty_new_line());