From f0d114aa8331ae8228ee32a4ffa9efd3953d8bf5 Mon Sep 17 00:00:00 2001
From: grcm10 <grcm10@outlook.com>
Date: Wed, 7 Feb 2024 20:48:39 +0900
Subject: [PATCH 1/2] Fix rethrowing the caught exception from streambuf

---
 stl/inc/ostream                               |  6 ++--
 .../GH_001858_iostream_exception/test.cpp     | 33 +++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/stl/inc/ostream b/stl/inc/ostream
index df2dd3f6b46..b2d718ef90b 100644
--- a/stl/inc/ostream
+++ b/stl/inc/ostream
@@ -493,8 +493,10 @@ public:
                 _TRY_BEGIN
                 _Meta = _Traits::eq_int_type(_Traits::eof(), _Meta) ? _Strbuf->sgetc() : _Strbuf->snextc();
                 _CATCH_ALL
-                _Myios::setstate(ios_base::failbit);
-                _RERAISE;
+                // N4971 [ostream.inserters]/8-9: "...If an exception was thrown
+                // while extracting a character, the function sets failbit in the error state,
+                // and if failbit is set in exceptions() the caught exception is rethrown."
+                _Myios::setstate(ios_base::failbit, (_Myios::exceptions() == ios_base::failbit));
                 _CATCH_END
 
                 if (_Traits::eq_int_type(_Traits::eof(), _Meta)) {
diff --git a/tests/std/tests/GH_001858_iostream_exception/test.cpp b/tests/std/tests/GH_001858_iostream_exception/test.cpp
index 9b9bc47ef29..257980fb310 100644
--- a/tests/std/tests/GH_001858_iostream_exception/test.cpp
+++ b/tests/std/tests/GH_001858_iostream_exception/test.cpp
@@ -36,6 +36,8 @@ struct test_exception {};
 template <class CharT>
 class throwing_buffer : public basic_streambuf<CharT> {
 public:
+    using typename basic_streambuf<CharT>::int_type;
+
     streampos seekoff(streamoff, ios_base::seekdir, ios_base::openmode = ios_base::in | ios_base::out) override {
         throw test_exception{};
     }
@@ -48,6 +50,10 @@ class throwing_buffer : public basic_streambuf<CharT> {
         throw test_exception{};
     }
 
+    int_type underflow() override {
+        throw test_exception{};
+    }
+
     basic_streambuf<CharT>* to_buf() {
         return this;
     }
@@ -229,6 +235,33 @@ void test_ostream_exceptions() {
             // Expected case
         }
     }
+
+    { // operator<< with exceptions
+        basic_ostream<CharT> os(buffer.to_buf());
+        os.exceptions(ios_base::goodbit);
+
+        try {
+            os << &buffer;
+        } catch (const ios_base::failure&) {
+            assert(false);
+        } catch (const test_exception&) {
+            assert(false);
+        }
+    }
+
+    { // operator<< rethrow the caught exception if failbit is set in exceptions()
+        basic_ostream<CharT> os(buffer.to_buf());
+        os.exceptions(ios_base::failbit);
+
+        try {
+            os << &buffer;
+            assert(false);
+        } catch (const ios_base::failure&) {
+            assert(false);
+        } catch (const test_exception&) {
+            // Expected case
+        }
+    }
 }
 
 // Also test strengthened and mandatory exception specifications.

From 8e681168baf027fa1c2c4fc31367f93da510d116 Mon Sep 17 00:00:00 2001
From: "Stephan T. Lavavej" <stl@nuwen.net>
Date: Wed, 7 Feb 2024 12:55:28 -0800
Subject: [PATCH 2/2] Code review feedback.

---
 stl/inc/ostream                                       | 4 ++--
 tests/std/tests/GH_001858_iostream_exception/test.cpp | 5 ++---
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/stl/inc/ostream b/stl/inc/ostream
index b2d718ef90b..970cd37b731 100644
--- a/stl/inc/ostream
+++ b/stl/inc/ostream
@@ -493,10 +493,10 @@ public:
                 _TRY_BEGIN
                 _Meta = _Traits::eq_int_type(_Traits::eof(), _Meta) ? _Strbuf->sgetc() : _Strbuf->snextc();
                 _CATCH_ALL
-                // N4971 [ostream.inserters]/8-9: "...If an exception was thrown
+                // N4971 [ostream.inserters]/9: "If an exception was thrown
                 // while extracting a character, the function sets failbit in the error state,
                 // and if failbit is set in exceptions() the caught exception is rethrown."
-                _Myios::setstate(ios_base::failbit, (_Myios::exceptions() == ios_base::failbit));
+                _Myios::setstate(ios_base::failbit, _Myios::exceptions() == ios_base::failbit);
                 _CATCH_END
 
                 if (_Traits::eq_int_type(_Traits::eof(), _Meta)) {
diff --git a/tests/std/tests/GH_001858_iostream_exception/test.cpp b/tests/std/tests/GH_001858_iostream_exception/test.cpp
index 257980fb310..5991d5e131d 100644
--- a/tests/std/tests/GH_001858_iostream_exception/test.cpp
+++ b/tests/std/tests/GH_001858_iostream_exception/test.cpp
@@ -236,9 +236,8 @@ void test_ostream_exceptions() {
         }
     }
 
-    { // operator<< with exceptions
+    { // operator<< (testing GH-4322 "<ostream>: Exception from streambuf should be caught and not rethrown")
         basic_ostream<CharT> os(buffer.to_buf());
-        os.exceptions(ios_base::goodbit);
 
         try {
             os << &buffer;
@@ -249,7 +248,7 @@ void test_ostream_exceptions() {
         }
     }
 
-    { // operator<< rethrow the caught exception if failbit is set in exceptions()
+    { // operator<< rethrows the caught exception if failbit is set in exceptions()
         basic_ostream<CharT> os(buffer.to_buf());
         os.exceptions(ios_base::failbit);