test/contrib: Fix invalid escapes in regex strings

Flagged by flake8 v3.6.0, as W605, plus a few others identified
incidentally, e.g. 59ffecf66cf4d08c4b431e457b083878d66a3fd6.

Note that r"\n" matches to "\n" under re.match/search.

contrib/devtools/clang-format-diff.py

@@ -106,7 +106,7 @@ def main():
   filename = None
   lines_by_file = {}
   for line in sys.stdin:
-    match = re.search('^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
+    match = re.search(r'^\+\+\+\ (.*?/){%s}(\S*)' % args.p, line)
     if match:
       filename = match.group(2)
     if filename is None:
@@ -119,7 +119,7 @@ def main():
       if not re.match('^%s$' % args.iregex, filename, re.IGNORECASE):
         continue
 
-    match = re.search('^@@.*\+(\d+)(,(\d+))?', line)
+    match = re.search(r'^@@.*\+(\d+)(,(\d+))?', line)
     if match:
       start_line = int(match.group(1))
       line_count = 1

contrib/devtools/copyright_header.py

@@ -71,7 +71,7 @@ def get_filenames_to_examine(base_directory):
 ################################################################################
 
 
-COPYRIGHT_WITH_C = 'Copyright \(c\)'
+COPYRIGHT_WITH_C = r'Copyright \(c\)'
 COPYRIGHT_WITHOUT_C = 'Copyright'
 ANY_COPYRIGHT_STYLE = '(%s|%s)' % (COPYRIGHT_WITH_C, COPYRIGHT_WITHOUT_C)
 
@@ -85,21 +85,21 @@ ANY_COPYRIGHT_STYLE_OR_YEAR_STYLE = ("%s %s" % (ANY_COPYRIGHT_STYLE,
 ANY_COPYRIGHT_COMPILED = re.compile(ANY_COPYRIGHT_STYLE_OR_YEAR_STYLE)
 
 def compile_copyright_regex(copyright_style, year_style, name):
-    return re.compile('%s %s,? %s' % (copyright_style, year_style, name))
+    return re.compile('%s %s,? %s\n' % (copyright_style, year_style, name))
 
 EXPECTED_HOLDER_NAMES = [
-    "Satoshi Nakamoto\n",
-    "The Bitcoin Core developers\n",
-    "BitPay Inc\.\n",
-    "University of Illinois at Urbana-Champaign\.\n",
-    "Pieter Wuille\n",
-    "Wladimir J. van der Laan\n",
-    "Jeff Garzik\n",
-    "Jan-Klaas Kollhof\n",
-    "ArtForz -- public domain half-a-node\n",
-    "Intel Corporation",
-    "The Zcash developers",
-    "Jeremy Rubin",
+    r"Satoshi Nakamoto",
+    r"The Bitcoin Core developers",
+    r"BitPay Inc\.",
+    r"University of Illinois at Urbana-Champaign\.",
+    r"Pieter Wuille",
+    r"Wladimir J\. van der Laan",
+    r"Jeff Garzik",
+    r"Jan-Klaas Kollhof",
+    r"ArtForz -- public domain half-a-node",
+    r"Intel Corporation ?",
+    r"The Zcash developers",
+    r"Jeremy Rubin",
 ]
 
 DOMINANT_STYLE_COMPILED = {}
@@ -329,7 +329,7 @@ def write_file_lines(filename, file_lines):
 # update header years execution
 ################################################################################
 
-COPYRIGHT = 'Copyright \(c\)'
+COPYRIGHT = r'Copyright \(c\)'
 YEAR = "20[0-9][0-9]"
 YEAR_RANGE = '(%s)(-%s)?' % (YEAR, YEAR)
 HOLDER = 'The Bitcoin Core developers'

contrib/devtools/symbol-check.py

@@ -141,7 +141,7 @@ def read_libraries(filename):
     for line in stdout.splitlines():
         tokens = line.split()
         if len(tokens)>2 and tokens[1] == '(NEEDED)':
-            match = re.match('^Shared library: \[(.*)\]$', ' '.join(tokens[2:]))
+            match = re.match(r'^Shared library: \[(.*)\]$', ' '.join(tokens[2:]))
             if match:
                 libraries.append(match.group(1))
             else:
@@ -171,5 +171,3 @@ if __name__ == '__main__':
                 retval = 1
 
     sys.exit(retval)
-
-