Fix Exception#detailed_message for GC compaction

peterzhu2118 · peterzhu2118 · commit b959263b58e2 · 2024-01-02T12:03:31.000-05:00
Before this commit, the test fails with RGENGC_CHECK_MODE enabled:

    TestException#test_detailed_message_under_gc_compact_stress [test/ruby/test_exception.rb:1466]:
    &lt;"\e[1mfoo (\e[1;4mRuntimeError\e[m\e[1m)\e[m\n" +
    "\e[1mbar\e[m\n" +
    "\e[1mbaz\e[m"&gt; expected but was
    &lt;"\e[1mfoo (\e[1;4mRuntimeError\e[m\e[1m)\e[m\n" +
    "\e[1m\x00\x00\x00\x00\x00\x00\x00\e[m"&gt;.
diff --git a/error.c b/error.c
@@ -1662,7 +1662,7 @@ exc_detailed_message(int argc, VALUE *argv, VALUE exc)
 
     VALUE highlight = check_highlight_keyword(opt, 0);
 
-    extern VALUE rb_decorate_message(const VALUE eclass, const VALUE emesg, int highlight);
+    extern VALUE rb_decorate_message(const VALUE eclass, VALUE emesg, int highlight);
 
     return rb_decorate_message(CLASS_OF(exc), rb_get_message(exc), RTEST(highlight));
 }
diff --git a/eval_error.c b/eval_error.c
@@ -125,7 +125,7 @@ print_errinfo(const VALUE eclass, const VALUE errat, const VALUE emesg, const VA
 }
 
 VALUE
-rb_decorate_message(const VALUE eclass, const VALUE emesg, int highlight)
+rb_decorate_message(const VALUE eclass, VALUE emesg, int highlight)
 {
     const char *einfo = "";
     long elen = 0;
@@ -210,6 +210,8 @@ rb_decorate_message(const VALUE eclass, const VALUE emesg, int highlight)
         }
     }
 
+    RB_GC_GUARD(emesg);
+
     return str;
 }
 
diff --git a/test/ruby/test_exception.rb b/test/ruby/test_exception.rb
@@ -1459,6 +1459,14 @@ def test_detailed_message
     assert_equal("\e[1mRuntimeError (\e[1;4mRuntimeError\e[m\e[1m)\e[m", e.detailed_message(highlight: true))
   end
 
+  def test_detailed_message_under_gc_compact_stress
+    EnvUtil.under_gc_compact_stress do
+      e = RuntimeError.new("foo\nbar\nbaz")
+      assert_equal("foo (RuntimeError)\nbar\nbaz", e.detailed_message)
+      assert_equal("\e[1mfoo (\e[1;4mRuntimeError\e[m\e[1m)\e[m\n\e[1mbar\e[m\n\e[1mbaz\e[m", e.detailed_message(highlight: true))
+    end
+  end
+
   def test_full_message_with_custom_detailed_message
     e = RuntimeError.new("message")
     opt_ = nil

Original file line number	Diff line number	Diff line change
`@@ -1662,7 +1662,7 @@ exc_detailed_message(int argc, VALUE *argv, VALUE exc)`
`1662`	`1662`
`1663`	`1663`	`VALUE highlight = check_highlight_keyword(opt, 0);`
`1664`	`1664`
`1665`		`- extern VALUE rb_decorate_message(const VALUE eclass, const VALUE emesg, int highlight);`
	`1665`	`+ extern VALUE rb_decorate_message(const VALUE eclass, VALUE emesg, int highlight);`
`1666`	`1666`
`1667`	`1667`	`return rb_decorate_message(CLASS_OF(exc), rb_get_message(exc), RTEST(highlight));`
`1668`	`1668`	`}`
Original file line number	Diff line number	Diff line change
`@@ -125,7 +125,7 @@ print_errinfo(const VALUE eclass, const VALUE errat, const VALUE emesg, const VA`
`125`	`125`	`}`
`126`	`126`
`127`	`127`	`VALUE`
`128`		`-rb_decorate_message(const VALUE eclass, const VALUE emesg, int highlight)`
	`128`	`+rb_decorate_message(const VALUE eclass, VALUE emesg, int highlight)`
`129`	`129`	`{`
`130`	`130`	`const char *einfo = "";`
`131`	`131`	`long elen = 0;`
`@@ -210,6 +210,8 @@ rb_decorate_message(const VALUE eclass, const VALUE emesg, int highlight)`
`210`	`210`	`}`
`211`	`211`	`}`
`212`	`212`
	`213`	`+ RB_GC_GUARD(emesg);`
	`214`	`+`
`213`	`215`	`return str;`
`214`	`216`	`}`
`215`	`217`