Index: clang/lib/Format/UnwrappedLineParser.cpp
===================================================================
--- clang/lib/Format/UnwrappedLineParser.cpp
+++ clang/lib/Format/UnwrappedLineParser.cpp
@@ -1282,10 +1282,10 @@
     if (FormatTok->Tok.is(tok::string_literal)) {
       nextToken();
       if (FormatTok->Tok.is(tok::l_brace)) {
+        if (Style.BraceWrapping.AfterExternBlock) {
+          addUnwrappedLine();
+        }
         if (!Style.IndentExternBlock) {
-          if (Style.BraceWrapping.AfterExternBlock) {
-            addUnwrappedLine();
-          }
           unsigned AddLevels = Style.BraceWrapping.AfterExternBlock ? 1u : 0u;
           parseBlock(/*MustBeDeclaration=*/true, AddLevels);
         } else {
Index: clang/unittests/Format/FormatTest.cpp
===================================================================
--- clang/unittests/Format/FormatTest.cpp
+++ clang/unittests/Format/FormatTest.cpp
@@ -3811,6 +3811,26 @@
                "int foo16();\n"
                "}",
                Style);
+
+  Style.IndentExternBlock = FormatStyle::IEBS_AfterExternBlock;
+  Style.BreakBeforeBraces = FormatStyle::BS_Custom;
+  Style.BraceWrapping.AfterExternBlock = true;
+  Style.IndentExternBlock = FormatStyle::IEBS_NoIndent;
+  verifyFormat("extern \"C\"\n{ /*13*/\n}", Style);
+  verifyFormat("extern \"C\"\n{\n"
+               "int foo14();\n"
+               "}",
+               Style);
+
+  Style.IndentExternBlock = FormatStyle::IEBS_AfterExternBlock;
+  Style.BreakBeforeBraces = FormatStyle::BS_Custom;
+  Style.BraceWrapping.AfterExternBlock = true;
+  Style.IndentExternBlock = FormatStyle::IEBS_Indent;
+  verifyFormat("extern \"C\"\n{ /*13*/\n}", Style);
+  verifyFormat("extern \"C\"\n{\n"
+               "  int foo14();\n"
+               "}",
+               Style);
 }
 
 TEST_F(FormatTest, FormatsInlineASM) {