3 files changed, 50 insertions, 3 deletions

diff --git a/absl/flags/flag.h b/absl/flags/flag.h
index 6c9f4876..36c771cf 100644
--- a/absl/flags/flag.h
+++ b/absl/flags/flag.h
@@ -217,7 +217,7 @@ void SetFlag(absl::Flag<T>* flag, const V& v) {
 // global name for FLAGS_no<flag_name> symbol, thus preventing the possibility
 // of defining two flags with names foo and nofoo.
 #define ABSL_FLAG_IMPL(Type, name, default_value, help)             \
-  namespace absl {}                                                 \
+  namespace absl /* block flags in namespaces */ {}                 \
   ABSL_FLAG_IMPL_DECLARE_DEF_VAL_WRAPPER(name, Type, default_value) \
   ABSL_FLAG_IMPL_DECLARE_HELP_WRAPPER(name, help)                   \
   ABSL_CONST_INIT absl::Flag<Type> FLAGS_##name(                    \
diff --git a/absl/flags/internal/usage.cc b/absl/flags/internal/usage.cc
index aac02db6..03048514 100644
--- a/absl/flags/internal/usage.cc
+++ b/absl/flags/internal/usage.cc
@@ -111,8 +111,16 @@ class FlagHelpPrettyPrinter {
 
     std::vector<absl::string_view> tokens;
     if (wrap_line) {
-      tokens = absl::StrSplit(str, absl::ByAnyChar(" \f\n\r\t\v"),
-                              absl::SkipEmpty());
+      for (auto line : absl::StrSplit(str, absl::ByAnyChar("\n\r"))) {
+        if (!tokens.empty()) {
+          // Keep line separators in the input std::string.
+          tokens.push_back("\n");
+        }
+        for (auto token :
+             absl::StrSplit(line, absl::ByAnyChar(" \t"), absl::SkipEmpty())) {
+          tokens.push_back(token);
+        }
+      }
     } else {
       tokens.push_back(str);
     }
@@ -120,6 +128,12 @@ class FlagHelpPrettyPrinter {
     for (auto token : tokens) {
       bool new_line = (line_len_ == 0);
 
+      // Respect line separators in the input std::string.
+      if (token == "\n") {
+        EndLine();
+        continue;
+      }
+
       // Write the token, ending the std::string first if necessary/possible.
       if (!new_line && (line_len_ + token.size() >= max_line_len_)) {
         EndLine();
diff --git a/absl/flags/internal/usage_test.cc b/absl/flags/internal/usage_test.cc
index 5e5f7a84..781e1d2b 100644
--- a/absl/flags/internal/usage_test.cc
+++ b/absl/flags/internal/usage_test.cc
@@ -48,6 +48,14 @@ std::string AbslUnparseFlag(const UDT&) { return "UDT{}"; }
 ABSL_FLAG(UDT, usage_reporting_test_flag_05, {},
           "usage_reporting_test_flag_05 help message");
 
+ABSL_FLAG(
+    std::string, usage_reporting_test_flag_06, {},
+    "usage_reporting_test_flag_06 help message.\n"
+    "\n"
+    "Some more help.\n"
+    "Even more long long long long long long long long long long long long "
+    "help message.");
+
 namespace {
 
 namespace flags = absl::flags_internal;
@@ -173,6 +181,11 @@ TEST_F(UsageReportingTest, TestFlagsHelpHRF) {
       default: 1000000000000004;
     -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
       default: UDT{};
+    -usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
+
+      Some more help.
+      Even more long long long long long long long long long long long long help
+      message.); default: "";
 )";
 
   std::stringstream test_buf_01;
@@ -244,6 +257,11 @@ TEST_F(UsageReportingTest, TestUsageFlag_helpshort) {
       default: 1000000000000004;
     -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
       default: UDT{};
+    -usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
+
+      Some more help.
+      Even more long long long long long long long long long long long long help
+      message.); default: "";
 )");
 }
 
@@ -268,6 +286,11 @@ TEST_F(UsageReportingTest, TestUsageFlag_help) {
       default: 1000000000000004;
     -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
       default: UDT{};
+    -usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
+
+      Some more help.
+      Even more long long long long long long long long long long long long help
+      message.); default: "";
 
 Try --helpfull to get a list of all flags.
 )");
@@ -294,6 +317,11 @@ TEST_F(UsageReportingTest, TestUsageFlag_helppackage) {
       default: 1000000000000004;
     -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
       default: UDT{};
+    -usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
+
+      Some more help.
+      Even more long long long long long long long long long long long long help
+      message.); default: "";
 
 Try --helpfull to get a list of all flags.
 )");
@@ -354,6 +382,11 @@ TEST_F(UsageReportingTest, TestUsageFlag_helpon) {
       default: 1000000000000004;
     -usage_reporting_test_flag_05 (usage_reporting_test_flag_05 help message);
       default: UDT{};
+    -usage_reporting_test_flag_06 (usage_reporting_test_flag_06 help message.
+
+      Some more help.
+      Even more long long long long long long long long long long long long help
+      message.); default: "";
 )");
 }