git-p4: use raw string literals for regular expressions

Fixes several Python diagnostics about invalid escape sequences. The
diagnostics appear for me in Python 3.12, and may appear in earlier
versions. The fix is to use raw string literals so that backslashes are
not interpreted as introducing escape sequences. Raw string literals
are already in use in this file, so adding more does not impact
toolchain compatibility.

Signed-off-by: James Touton <bekenn@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-p4.py

@@ -689,8 +689,8 @@ def setP4ExecBit(file, mode):
 
     if not isModeExec(mode):
         p4Type = getP4OpenedType(file)
-        p4Type = re.sub('^([cku]?)x(.*)', '\\1\\2', p4Type)
-        p4Type = re.sub('(.*?\+.*?)x(.*?)', '\\1\\2', p4Type)
+        p4Type = re.sub(r'^([cku]?)x(.*)', r'\1\2', p4Type)
+        p4Type = re.sub(r'(.*?\+.*?)x(.*?)', r'\1\2', p4Type)
         if p4Type[-1] == "+":
             p4Type = p4Type[0:-1]
 
@@ -701,7 +701,7 @@ def getP4OpenedType(file):
     """Returns the perforce file type for the given file."""
 
     result = p4_read_pipe(["opened", wildcard_encode(file)])
-    match = re.match(".*\((.+)\)( \*exclusive\*)?\r?$", result)
+    match = re.match(r".*\((.+)\)( \*exclusive\*)?\r?$", result)
     if match:
         return match.group(1)
     else:
@@ -757,7 +757,7 @@ def parseDiffTreeEntry(entry):
 
     global _diff_tree_pattern
     if not _diff_tree_pattern:
-        _diff_tree_pattern = re.compile(':(\d+) (\d+) (\w+) (\w+) ([A-Z])(\d+)?\t(.*?)((\t(.*))|$)')
+        _diff_tree_pattern = re.compile(r':(\d+) (\d+) (\w+) (\w+) ([A-Z])(\d+)?\t(.*?)((\t(.*))|$)')
 
     match = _diff_tree_pattern.match(entry)
     if match:
@@ -918,9 +918,9 @@ def p4CmdList(cmd, stdin=None, stdin_mode='w+b', cb=None, skip_info=False,
             if len(result) > 0:
                 data = result[0].get('data')
                 if data:
-                    m = re.search('Too many rows scanned \(over (\d+)\)', data)
+                    m = re.search(r'Too many rows scanned \(over (\d+)\)', data)
                     if not m:
-                        m = re.search('Request too large \(over (\d+)\)', data)
+                        m = re.search(r'Request too large \(over (\d+)\)', data)
 
                     if m:
                         limit = int(m.group(1))
@@ -1452,7 +1452,7 @@ def wildcard_encode(path):
 
 
 def wildcard_present(path):
-    m = re.search("[*#@%]", path)
+    m = re.search(r"[*#@%]", path)
     return m is not None
 
 
@@ -3048,7 +3048,7 @@ class P4Sync(Command, P4UserMap):
             # Preserve everything in relative path name except leading
             # //depot/; just look at first prefix as they all should
             # be in the same depot.
-            depot = re.sub("^(//[^/]+/).*", r'\1', prefixes[0])
+            depot = re.sub(r"^(//[^/]+/).*", r'\1', prefixes[0])
             if p4PathStartsWith(path, depot):
                 path = path[len(depot):]
 
@@ -3603,7 +3603,7 @@ class P4Sync(Command, P4UserMap):
                     commitFound = True
                 else:
                     gitCommit = read_pipe(["git", "rev-list", "--max-count=1",
-                        "--reverse", ":/\[git-p4:.*change = %d\]" % changelist], ignore_error=True)
+                        "--reverse", r":/\[git-p4:.*change = %d\]" % changelist], ignore_error=True)
                     if len(gitCommit) == 0:
                         print("importing label %s: could not find git commit for changelist %d" % (name, changelist))
                     else:
@@ -4182,7 +4182,7 @@ class P4Sync(Command, P4UserMap):
                 if len(self.changesFile) == 0:
                     revision = "#head"
 
-            p = re.sub("\.\.\.$", "", p)
+            p = re.sub(r"\.\.\.$", "", p)
             if not p.endswith("/"):
                 p += "/"
 
@@ -4291,7 +4291,7 @@ class P4Rebase(Command):
             die("Cannot find upstream branchpoint for rebase")
 
         # the branchpoint may be p4/foo~3, so strip off the parent
-        upstream = re.sub("~[0-9]+$", "", upstream)
+        upstream = re.sub(r"~[0-9]+$", "", upstream)
 
         print("Rebasing the current branch onto %s" % upstream)
         oldHead = read_pipe(["git", "rev-parse", "HEAD"]).strip()
@@ -4320,8 +4320,8 @@ class P4Clone(P4Sync):
     def defaultDestination(self, args):
         # TODO: use common prefix of args?
         depotPath = args[0]
-        depotDir = re.sub("(@[^@]*)$", "", depotPath)
-        depotDir = re.sub("(#[^#]*)$", "", depotDir)
+        depotDir = re.sub(r"(@[^@]*)$", "", depotPath)
+        depotDir = re.sub(r"(#[^#]*)$", "", depotDir)
         depotDir = re.sub(r"\.\.\.$", "", depotDir)
         depotDir = re.sub(r"/$", "", depotDir)
         return os.path.split(depotDir)[1]