Fix handling of null strings with the s specifier

fmtlib · Nov 16, 2023 · 649fe0f · 649fe0f
1 parent 45e124e
commit 649fe0f
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Showing 2 changed files with 9 additions and 4 deletions.
diff --git a/include/fmt/format.h b/include/fmt/format.h
@@ -2342,9 +2342,10 @@ template <typename Char, typename OutputIt>
 FMT_CONSTEXPR auto write(OutputIt out, const Char* s,
                          const format_specs<Char>& specs, locale_ref)
     -> OutputIt {
-  return specs.type != presentation_type::pointer
-             ? write(out, basic_string_view<Char>(s), specs, {})
-             : write_ptr<Char>(out, bit_cast<uintptr_t>(s), &specs);
+  if (specs.type == presentation_type::pointer)
+    return write_ptr<Char>(out, bit_cast<uintptr_t>(s), &specs);
+  if (!s) throw_format_error("string pointer is null");
+  return write(out, basic_string_view<Char>(s), specs, {});
 }
 
 template <typename Char, typename OutputIt, typename T,

diff --git a/test/format-test.cc b/test/format-test.cc
@@ -1531,8 +1531,12 @@ TEST(format_test, format_cstring) {
   EXPECT_EQ("test", fmt::format("{0:s}", "test"));
   char nonconst[] = "nonconst";
   EXPECT_EQ("nonconst", fmt::format("{0}", nonconst));
+  auto nullstr = static_cast<const char*>(nullptr);
   EXPECT_THROW_MSG(
-      (void)fmt::format(runtime("{0}"), static_cast<const char*>(nullptr)),
+      (void)fmt::format("{}", nullstr),
+      format_error, "string pointer is null");
+  EXPECT_THROW_MSG(
+      (void)fmt::format("{:s}", nullstr),
       format_error, "string pointer is null");
 }