[Lldb-commits] [clang] [clang-tools-extra] [compiler-rt] [libcxx] [lld] [lldb] [llvm] [mlir] [polly] fix(python): fix invalid escape sequences (PR #91856)

[Eisuke Kawashima via lldb-commits]

e-kwsm wrote:

> Why do we need to make this change?

The valid escape sequences in Python are listed [here](https://docs.python.org/3/reference/lexical_analysis.html#escape-sequences): `\t`, `\n`, etc.

Invalid ones fixed here seem to be used for regular expression, [re](https://docs.python.org/3/library/re.html), e.g. `\.` for literal dot, `\d` for a digit `[0-9]`.

I use [flake8](https://flake8.pycqa.org/en/latest/) for check.

> Did you use a script to generate this patch?

No. We have choices to fix these:

1. escape backslashes: `"\s"` -> `"\\s"`
2. use raw string: `"\s"` -> `r"\s"`

I thought 2 is simple but actually it does not work for e.g.:

```diff
--- a/clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py
+++ b/clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py
@@ -242,7 +242,7 @@ def main():
     filename = None
     lines_by_file = {}
     for line in sys.stdin:
-        match = re.search('^\+\+\+\ "?(.*?/){%s}([^ \t\n"]*)' % args.p, line)
+        match = re.search('^\\+\\+\\+\\ "?(.*?/){%s}([^ \t\n"]*)' % args.p, line)
         if match:
             filename = match.group(2)
         if filename is None:
```

Here `\t\n` is valid whereas `\+` is not.

So I manually fixed them.

https://github.com/llvm/llvm-project/pull/91856