From 50cb9a655d207b99136fde31ecfa56908e4c57b3 Mon Sep 17 00:00:00 2001
From: Ayush Choudhary <87753540+ayushch80@users.noreply.github.com>
Date: Fri, 2 Jan 2026 15:19:52 +0530
Subject: [PATCH] vrepl: fix handling of `//` inside string literals (fix
 #25603) (#26240)

---
 cmd/tools/vrepl.v                        | 53 +++++++++++++++++++++++-
 vlib/v/slow_tests/repl/line_comment.repl | 30 ++++++++++++++
 vlib/v/slow_tests/repl/runner/runner.v   |  2 +-
 3 files changed, 82 insertions(+), 3 deletions(-)

diff --git a/cmd/tools/vrepl.v b/cmd/tools/vrepl.v
index ada995bda..441582192 100644
--- a/cmd/tools/vrepl.v
+++ b/cmd/tools/vrepl.v
@@ -48,7 +48,6 @@ const repl_folder = os.join_path(os.vtmp_dir(), 'repl')
 const possible_statement_patterns = [
 	'++',
 	'--',
-	'//',
 	'/*',
 	'assert ',
 	'fn ',
@@ -410,6 +409,54 @@ fn print_welcome_screen() {
 	}
 }
 
+fn remove_comment(oline string) string {
+	mut inside_string := false
+	mut escaped := false
+	mut maybe_comment := false
+
+	mut string_delim := 0
+
+	mut i := 0
+	for i < oline.len {
+		match oline[i] {
+			`"`, `'` {
+				if !escaped {
+					if inside_string && string_delim == oline[i] {
+						inside_string = false
+					} else if !inside_string {
+						inside_string = true
+						maybe_comment = false
+						string_delim = oline[i]
+					}
+				} else {
+					escaped = false
+				}
+			}
+			`\\` {
+				if inside_string {
+					escaped = !escaped
+				}
+			}
+			`/` {
+				if maybe_comment {
+					i--
+					break
+				} else if !inside_string {
+					maybe_comment = true
+				}
+			}
+			else {
+				escaped = false
+				maybe_comment = false
+			}
+		}
+
+		i++
+	}
+
+	return oline[..i]
+}
+
 fn run_repl(workdir string, vrepl_prefix string) int {
 	if !is_stdin_a_pipe {
 		print_welcome_screen()
@@ -440,8 +487,10 @@ fn run_repl(workdir string, vrepl_prefix string) int {
 		} else {
 			prompt = '... '
 		}
+
 		oline := r.get_one_line(prompt) or { break }
-		line := oline.all_before('//').trim_space()
+		line := remove_comment(oline).trim_space()
+
 		if line == '' {
 			continue
 		}
diff --git a/vlib/v/slow_tests/repl/line_comment.repl b/vlib/v/slow_tests/repl/line_comment.repl
index 9218e2c41..c63730611 100644
--- a/vlib/v/slow_tests/repl/line_comment.repl
+++ b/vlib/v/slow_tests/repl/line_comment.repl
@@ -1,5 +1,35 @@
 math.pi
 math.pi // some comment
+"a//b"
+"a \" // b"
+"a 'b' // ok"
+"http://example.com"
+"http://example.com" // comment
+"\\\\//"
+"\\\\//" // comment
+"\"//\""
+"\"\\\"//\""
+"end\"" // comment
+"end\\\"" // comment
+"π // inside"
+"π \\\" // inside"
+1 // 2 // 3
+42//comment
 ===output===
 3.141592653589793
 3.141592653589793
+a//b
+a " // b
+a 'b' // ok
+http://example.com
+http://example.com
+\\//
+\\//
+"//"
+"\"//"
+end"
+end\"
+π // inside
+π \" // inside
+1
+42
diff --git a/vlib/v/slow_tests/repl/runner/runner.v b/vlib/v/slow_tests/repl/runner/runner.v
index c14bca1b6..962afd6be 100644
--- a/vlib/v/slow_tests/repl/runner/runner.v
+++ b/vlib/v/slow_tests/repl/runner/runner.v
@@ -56,7 +56,7 @@ pub fn run_repl_file(wd string, vexec string, file string) !string {
 		return error('Could not execute: ${rcmd}')
 	}
 	result := r.output.replace_each(['\r', '', '>>> ', '', '>>>', '', '... ', '',
-		wd + os.path_separator, '', vexec_folder, '', '\\', '/']).trim_right('\n\r')
+		wd + os.path_separator, '', vexec_folder, '']).trim_right('\n\r')
 	$if windows {
 		dump(rcmd)
 		dump(r.output)
-- 
2.39.5