From 2aa8a3502fd049a3ce13164aa8b289daf2940e04 Mon Sep 17 00:00:00 2001
From: Sudhakar Verma <sudhakar.verma@canonical.com>
Date: Fri, 12 Jan 2024 16:08:47 +0530
Subject: [PATCH] printf : no infinite loop

---
 src/uu/printf/src/printf.rs  | 10 +++++++++-
 tests/by-util/test_printf.rs |  5 +++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/uu/printf/src/printf.rs b/src/uu/printf/src/printf.rs
index ad42e3894..64a3a35a7 100644
--- a/src/uu/printf/src/printf.rs
+++ b/src/uu/printf/src/printf.rs
@@ -11,7 +11,7 @@ use std::ops::ControlFlow;
 
 use clap::{crate_version, Arg, ArgAction, Command};
 use uucore::error::{UResult, UUsageError};
-use uucore::format::{parse_spec_and_escape, FormatArgument};
+use uucore::format::{parse_spec_and_escape, FormatArgument, FormatItem};
 use uucore::{format_usage, help_about, help_section, help_usage};
 
 const VERSION: &str = "version";
@@ -46,6 +46,14 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
         };
     }
 
+    // See #5815 - We don't need to iter on args if no format string seen
+    let format_seen = parse_spec_and_escape(format_string.as_ref())
+        .into_iter()
+        .any(|r| matches!(r, Ok(FormatItem::Spec(_))));
+    if !format_seen {
+        return Ok(());
+    }
+
     while args.peek().is_some() {
         for item in parse_spec_and_escape(format_string.as_ref()) {
             match item?.write(stdout(), &mut args)? {
diff --git a/tests/by-util/test_printf.rs b/tests/by-util/test_printf.rs
index 4f2e1dc10..411285a0c 100644
--- a/tests/by-util/test_printf.rs
+++ b/tests/by-util/test_printf.rs
@@ -649,3 +649,8 @@ fn partial_char() {
 fn char_as_byte() {
     new_ucmd!().args(&["%c", "🙃"]).succeeds().stdout_only("ð");
 }
+
+#[test]
+fn no_infinite_loop() {
+    new_ucmd!().args(&["a", "b"]).succeeds().stdout_only("a");
+}