scan-build-py: Force the opening in utf-8

[sylvestre.ledru]

Summary

It fails on ubuntu bionic otherwise with:

scan-build-py-14: Run 'scan-view /tmp/scan-build-2021-08-09-09-14-36-765350-nx9s888s' to examine bug reports.
scan-build-py-14: Internal error.
Traceback (most recent call last):
  File "/usr/lib/llvm-14/lib/libscanbuild/__init__.py", line 125, in wrapper
    return function(*args, **kwargs)
  File "/usr/lib/llvm-14/lib/libscanbuild/analyze.py", line 72, in scan_build
    number_of_bugs = document(args)
  File "/usr/lib/llvm-14/lib/libscanbuild/report.py", line 35, in document
    for bug in read_bugs(args.output, html_reports_available):
  File "/usr/lib/llvm-14/lib/libscanbuild/report.py", line 282, in read_bugs
    for bug in parser(bug_file):
  File "/usr/lib/llvm-14/lib/libscanbuild/report.py", line 421, in parse_bug_html
    for line in handler.readlines():
  File "/usr/lib/python3.6/encodings/ascii.py", line 26, in decode
    return codecs.ascii_decode(input, self.errors)[0]
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 3360: ordinal not in range(128)
scan-build-py-14: Please run this command again and turn on verbose mode (add '-vvvv' as argument).

I guess it is caused by a problem in Python 3.6

[isthismyaccount]

Seems reasonable to me.

[phosek]

LGTM

clang/tools/scan-build-py/lib/libscanbuild/report.py

420

The rest of this file uses ' rather than " for strings, can we keep it consistent?

[sylvestre.ledru]

Replace " => '

clang/tools/scan-build-py/lib/libscanbuild/report.py

def parse_bug_html(filename):
     bug = {
         'report_file': filename,
         'bug_function': 'n/a',  # compatibility with < clang-3.5
         'bug_category': 'Other',
         'bug_line': 0,
         'bug_path_length': 1
     }
 
-    with open(filename) as handler:
+    with open(filename, encoding='utf-8') as handler:
         for line in handler.readlines():
             # do not read the file further
             if endsign.match(line):
                 break
             # search for the right lines
             for regex in patterns:
                 match = regex.match(line.strip())
                 if match: