clang-format 7 and later cannot read RawStringFormats from 6.0

[Rondom]

Bugzilla Link	45337
Version	trunk
OS	Linux
Attachments	clang-format-file that works fine with 6.0 but not with later versions

Extended Description

Between clang-format 6.0 and 7.0, the format of the RawStringFormats property has changed. Instead of taking a string of one delimiter per list item (key "Delimiter") it takes multiple delimiters as a list (key "Delimiters") per list item in later versions of clang-format.

My expectation is that later versions of clang-format can process a .clang-format file produced with an earlier version of clang-format using the --dump-config switch without any manual changes.

https://releases.llvm.org/6.0.0/tools/clang/docs/ClangFormatStyleOptions.html#configurable-format-style-options
https://releases.llvm.org/7.0.0/tools/clang/docs/ClangFormatStyleOptions.html#configurable-format-style-options

To reproduce:

1. Either
   a. Produce a .clang-format file using clang-format-6.0 --dump-config
   b. Create a .clang-format file with the following content (also attached)

---

Language: Cpp
RawStringFormats:

• Delimiter: pb
  Language: TextProto
  BasedOnStyle: google
  ...

2. Run latest clang-format on some file, e.g. clang-format -i main.cpp

Actual behaviour:

~/clang-format-test
❯ clang-format-6.0 -i main.cpp

~/clang-format-test
❯ clang-format-10 -i main.cpp

YAML:4:16: error: unknown key 'Delimiter'

• Delimiter: pb
  ^~
  Error reading /home/tobii.intra/ag3512/clang-format-test/.clang-format: Invalid argument

~/clang-format-test

Expected behaviour:

The latest versionof clang-format should be able to format files just fine using the old .clang-format file.

[mydeveloperday]

I'm going to close this issue as I see no need for us to support .clang-format versions from 7 versions back. If you are still concerned please reopen this but I think our time is better spent on the other 500+ open issues.