From 6b1801063b7078c8d9357f0ac8447202f3335f1b Mon Sep 17 00:00:00 2001
From: Kurtis Rader <krader@skepticism.us>
Date: Mon, 29 Aug 2016 20:11:40 -0700
Subject: [PATCH] fix raw_string_to_scalar_type locale handling

Fixes #3334
---
 src/builtin_printf.cpp | 17 +++++++++++++----
 tests/printf.err       |  1 +
 tests/printf.in        |  9 ++++++++-
 tests/printf.out       |  3 +++
 4 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/src/builtin_printf.cpp b/src/builtin_printf.cpp
index 9f3ea7bc5..35e5b18d4 100644
--- a/src/builtin_printf.cpp
+++ b/src/builtin_printf.cpp
@@ -264,11 +264,20 @@ uintmax_t raw_string_to_scalar_type(const wchar_t *s, wchar_t **end) {
 
 template <>
 long double raw_string_to_scalar_type(const wchar_t *s, wchar_t **end) {
-    // Forcing the locale to C is questionable but it's what the old C_STRTOD() that I inlined here
-    // as part of changing how locale management is done by fish.
-    char *old_locale = setlocale(LC_NUMERIC, "C");
     double val = wcstod(s, end);
-    setlocale(LC_NUMERIC, old_locale);
+    if (**end == L'\0') return val;
+
+    // The conversion using the user's locale failed. That may be due to the string not being a
+    // valid floating point value. It could also be due to the locale using different separator
+    // characters than the normal english convention. So try again by forcing the use of a locale
+    // that employs the english convention for writing floating point numbers.
+    //
+    // TODO: switch to the wcstod_l() function to avoid changing the global locale.
+    char *saved_locale = strdup(setlocale(LC_NUMERIC, NULL));
+    setlocale(LC_NUMERIC, "C");
+    val = wcstod(s, end);
+    setlocale(LC_NUMERIC, saved_locale);
+    free(saved_locale);
     return val;
 }
 
diff --git a/tests/printf.err b/tests/printf.err
index e69de29bb..8ba50d3ff 100644
--- a/tests/printf.err
+++ b/tests/printf.err
@@ -0,0 +1 @@
+2,34: value not completely converted
diff --git a/tests/printf.in b/tests/printf.in
index 78c0d9771..01f8b2645 100644
--- a/tests/printf.in
+++ b/tests/printf.in
@@ -34,4 +34,11 @@ printf "%5" 10 ^ /dev/null
 # \376 is 0xFE
 printf '\376' | xxd -p
 
-true
+# Verify that floating point conversions and output work correctly with
+# different combinations of locales and floating point strings. See issue
+# #3334. This starts by assuming an locale using english conventions.
+printf '%e\n' "1.23"  # should succeed, output should be 1.230000e+00
+printf '%e\n' "2,34"  # should fail
+set -x LC_NUMERIC fr_FR.UTF-8
+printf '%e\n' "3,45"  # should succeed, output should be 3,450000e+00
+printf '%e\n' "4.56"  # should succeed, output should be 4,560000e+00
diff --git a/tests/printf.out b/tests/printf.out
index f1c1960ba..5349b0fbf 100644
--- a/tests/printf.out
+++ b/tests/printf.out
@@ -14,3 +14,6 @@ I P Q R
 Test escapes
 a
 fe
+1.230000e+00
+3,450000e+00
+4,560000e+00