[clang] Issue143668 (PR #149396)

[David Spickett via cfe-commits]

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@@ -158,12 +158,12 @@ TEST_F(InterpreterTest, UndoCommand) {
 
   // Fail to undo.
   auto Err1 = Interp->Undo();
-  EXPECT_EQ("Operation failed. Too many undos",
+  EXPECT_EQ("Operation failed. No input left to undo",
             llvm::toString(std::move(Err1)));
   auto Err2 = Interp->Parse("int foo = 42;");
   EXPECT_TRUE(!!Err2);
   auto Err3 = Interp->Undo(2);
-  EXPECT_EQ("Operation failed. Too many undos",
+  EXPECT_EQ("Operation failed. No input left to undo",
----------------
DavidSpickett wrote:

https://github.com/llvm/llvm-project/blob/d883d5fecf8aa7db6daa0b163599d42ca00c5808/lldb/source/Plugins/SymbolFile/CTF/SymbolFileCTF.cpp#L338 is an example of formatting an error message.

If you've seen Python's format strings, it works like those, automatically figuring out what the type of the parameters are so that you don't have to `%<something>` each time. There's a bit more explanation in https://llvm.org/doxygen/FormatVariadic_8h_source.html but searching for other uses of it will be more informative than the formal grammar of it.

https://github.com/llvm/llvm-project/pull/149396