[clang-format] PR35514 brace-init member initializers in function-try-blocks are not formatted correctly

[MyDeveloperDay]

Summary

https://bugs.llvm.org/show_bug.cgi?id=35514

Initializer lists with a try-block are incorrectly formatted.

e.g.

Foo(int abc, int def) try : _abc(abc), _def{def}, _ghi{1} {
  callA();
  callB();
} catch (std::exception&) {
}

is formatted as:

Foo(int abc, int def) try : _abc(abc), _def { def }
, _ghi{1} {
  callA();
  callB();
}
catch (std::exception&) {
}

This revision adds support in the parseTryCatch for braced initializers in the initializer list

[curdeius]

I'd like to see a test with braces inside the try (intoducing scope), just to verify it doesn't break.

E.g.:

verifyFormat("class A {\n"
             "  int a;\n"
             "  A() try : a(0), b{1}, c{2} {\n"
             "    { // New scope.\n"
             "    }\n"
             "  } catch (...) {\n"
             "    throw;\n"
             "  }\n"
             "};\n");

Otherwise LGTM.

[MyDeveloperDay]

In D93296#2457366, @curdeius wrote:

I'd like to see a test with braces inside the try (intoducing scope), just to verify it doesn't break.

Sure let me add that.

[MyDeveloperDay]

Add additional unit test

clang/lib/Format/UnwrappedLineParser.cpp

if (FormatTok->is(tok::colon)) {
     // multiple commas in sequence - before the first identifier.
     while (FormatTok->is(tok::comma))
       nextToken();
 
     while (FormatTok->is(tok::identifier)) {
       nextToken();
       if (FormatTok->is(tok::l_paren))
         parseParens();
+      if (FormatTok->Previous && FormatTok->Previous->is(tok::identifier) &&
+          FormatTok->is(tok::l_brace)) {
+        do {
+          nextToken();
+        } while (!FormatTok->is(tok::r_brace));
+        nextToken();
+      }
 
       // In case identifiers were removed by clang-tidy, what might follow is
       // multiple commas in sequence - after the first identifier.
       while (FormatTok->is(tok::comma))
         nextToken();
     }
   }
   // Parse try with resource.

clang/unittests/Format/FormatTest.cpp

verifyFormat("int f() try { return 4; } catch (...) {\n"
                "}");
   verifyFormat("class A {\n"
                "  int a;\n"
                "  A() try : a(0) {\n"
                "  } catch (...) {\n"
                "    throw;\n"
                "  }\n"
                "};\n");
+  verifyFormat("class A {\n"
+               "  int a;\n"
+               "  A() try : a(0), b{1} {\n"
+               "  } catch (...) {\n"
+               "    throw;\n"
+               "  }\n"
+               "};\n");
+  verifyFormat("class A {\n"
+               "  int a;\n"
+               "  A() try : a(0), b{1}, c{2} {\n"
+               "  } catch (...) {\n"
+               "    throw;\n"
+               "  }\n"
+               "};\n");
+  verifyFormat("class A {\n"
+               "  int a;\n"
+               "  A() try : a(0), b{1}, c{2} {\n"
+               "    { // New scope.\n"
+               "    }\n"
+               "  } catch (...) {\n"
+               "    throw;\n"
+               "  }\n"
+               "};\n");
 
   // Incomplete try-catch blocks.
   verifyIncompleteFormat("try {} catch (");
 }
 
 TEST_F(FormatTest, FormatTryAsAVariable) {
   verifyFormat("int try;");
   verifyFormat("int try, size;");
TEST_F(FormatTest, UnderstandsUnaryOperators) {
 
   verifyFormat("int a = /* confusing comment */ -1;");
   // FIXME: The space after 'i' is wrong, but hopefully, this is a rare case.
   verifyFormat("int a = i /* confusing comment */++;");
 
   verifyFormat("co_yield -1;");
   verifyFormat("co_return -1;");
 
-  // Check that * is not treated as a binary operator when we set PointerAlignment
-  // as PAS_Left after a keyword and not a declaration.
+  // Check that * is not treated as a binary operator when we set
+  // PointerAlignment as PAS_Left after a keyword and not a declaration.
   FormatStyle PASLeftStyle = getLLVMStyle();
   PASLeftStyle.PointerAlignment = FormatStyle::PAS_Left;
   verifyFormat("co_return *a;", PASLeftStyle);
   verifyFormat("co_await *a;", PASLeftStyle);
   verifyFormat("co_yield *a", PASLeftStyle);
   verifyFormat("return *a;", PASLeftStyle);
 }