From 47835031850cb3188d5b4b119cc629e393a11ca7 Mon Sep 17 00:00:00 2001
From: Lukas Neubert <serkonda@protonmail.com>
Date: Mon, 28 Dec 2020 17:14:55 +0100
Subject: [PATCH] fmt: keep interface comments between methods (#7650)

---
 vlib/v/ast/ast.v                              |  1 +
 vlib/v/fmt/fmt.v                              |  1 +
 .../interface_declaration_comments_keep.vv    | 27 +++++++++++++++++++
 vlib/v/parser/struct.v                        |  4 ++-
 4 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 4fb613dea7..72f08e71d2 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -312,6 +312,7 @@ pub mut:
 	stmts           []Stmt
 	return_type     table.Type
 	comments        []Comment // comments *after* the header, but *before* `{`; used for InterfaceDecl
+	next_comments   []Comment // coments that are one line after the decl; used for InterfaceDecl
 	source_file     &File = 0
 	scope           &Scope
 }
diff --git a/vlib/v/fmt/fmt.v b/vlib/v/fmt/fmt.v
index d6e2e13abc..93d041188c 100644
--- a/vlib/v/fmt/fmt.v
+++ b/vlib/v/fmt/fmt.v
@@ -715,6 +715,7 @@ pub fn (mut f Fmt) interface_decl(node ast.InterfaceDecl) {
 		f.write(method.stringify(f.table, f.cur_mod, f.mod2alias).after('fn '))
 		f.comments(method.comments, inline: true, has_nl: false, level: .indent)
 		f.writeln('')
+		f.comments(method.next_comments, inline: false, has_nl: true, level: .indent)
 	}
 	f.writeln('}\n')
 }
diff --git a/vlib/v/fmt/tests/interface_declaration_comments_keep.vv b/vlib/v/fmt/tests/interface_declaration_comments_keep.vv
index d4404263db..60c8312c77 100644
--- a/vlib/v/fmt/tests/interface_declaration_comments_keep.vv
+++ b/vlib/v/fmt/tests/interface_declaration_comments_keep.vv
@@ -2,3 +2,30 @@ pub interface ReaderWriter {
 	read(mut buf []byte) ?int // from Reader
 	write(buf []byte) ?int // from Writer
 }
+
+interface Speaker {
+	// first
+	speak() string
+	// between
+	foo() string
+	foo2() string
+	// last
+}
+
+interface Baz {
+	// first
+	speak() string
+	// comment
+	// more between
+	foo() string
+	foo2() string
+	// last
+}
+
+interface Bar {
+	speak() string // after
+	foo() string
+	speak2() string // also after
+	// and between
+	foo2() string
+}
diff --git a/vlib/v/parser/struct.v b/vlib/v/parser/struct.v
index 086284d562..f2fd7a9eef 100644
--- a/vlib/v/parser/struct.v
+++ b/vlib/v/parser/struct.v
@@ -455,8 +455,10 @@ fn (mut p Parser) interface_decl() ast.InterfaceDecl {
 		if p.tok.kind.is_start_of_type() && p.tok.line_nr == line_nr {
 			method.return_type = p.parse_type()
 		}
-		mcomments := p.eat_comments()
+		mcomments := p.eat_line_end_comments()
+		mnext_comments := p.eat_comments()
 		method.comments = mcomments
+		method.next_comments = mnext_comments
 		methods << method
 		// println('register method $name')
 		ts.register_method(name: name, params: args, return_type: method.return_type, is_pub: true)