use __contains__, index or split instead of str.find

str.find return -1 when the substring is not found, -1 evaluate
to True and is a valid index, which can lead to bugs.
Using alternatives when possible makes the code clearer and less
prone to bugs. (and __contains__ is faster in microbenchmarks)

mercurial/commands.py

@@ -231,7 +231,7 b' def revrange(ui, repo, revs):'
     """Yield revision as strings from a list of revision specifications."""
     seen = {}
     for spec in revs:
-        if spec.find(revrangesep) >= 0:
+        if revrangesep in spec:
             start, end = spec.split(revrangesep, 1)
             start = revfix(repo, start, 0)
             end = revfix(repo, end, repo.changelog.count() - 1)
@@ -2742,7 +2742,7 b' def tag(ui, repo, name, rev_=None, **opt'
 
     disallowed = (revrangesep, '\r', '\n')
     for c in disallowed:
-        if name.find(c) >= 0:
+        if c in name:
             raise util.Abort(_("%s cannot be used in a tag name") % repr(c))
 
     repo.hook('pretag', throw=True, node=r, tag=name,

mercurial/filelog.py

@@ -34,14 +34,14 b' class filelog(revlog):'
         t = self.revision(node)
         if not t.startswith('\1\n'):
             return t
-        s = t.find('\1\n', 2)
+        s = t.index('\1\n', 2)
         return t[s+2:]
 
     def readmeta(self, node):
         t = self.revision(node)
         if not t.startswith('\1\n'):
             return {}
-        s = t.find('\1\n', 2)
+        s = t.index('\1\n', 2)
         mt = t[2:s]
         m = {}
         for l in mt.splitlines():

mercurial/hg.py

@@ -61,8 +61,7 b' def repository(ui, path=None, create=0):'
     if not path: path = ''
     scheme = path
     if scheme:
-        c = scheme.find(':')
-        scheme = c >= 0 and scheme[:c]
+        scheme = scheme.split(":", 1)[0]
     ctor = schemes.get(scheme) or schemes['file']
     if create:
         try:

mercurial/hgweb/hgweb_mod.py

@@ -462,7 +462,7 b' class hgweb(object):'
                 continue
             remain = f[l:]
             if "/" in remain:
-                short = remain[:remain.find("/") + 1] # bleah
+                short = remain[:remain.index("/") + 1] # bleah
                 files[short] = (f, None)
             else:
                 short = os.path.basename(remain)

mercurial/lock.py

@@ -85,14 +85,14 b' class lock(object):'
         # see if locker is alive.  if locker is on this machine but
         # not alive, we can safely break lock.
         locker = util.readlock(self.f)
-        c = locker.find(':')
-        if c == -1:
+        try:
+            host, pid = locker.split(":", 1)
+        except ValueError:
             return locker
-        host = locker[:c]
         if host != self.host:
             return locker
         try:
-            pid = int(locker[c+1:])
+            pid = int(pid)
         except:
             return locker
         if util.testpid(pid):

mercurial/ui.py

@@ -76,7 +76,7 b' class ui(object):'
         if root is None:
             root = os.path.expanduser('~')
         for name, path in self.configitems("paths"):
-            if path and path.find("://") == -1 and not os.path.isabs(path):
+            if path and "://" not in path and not os.path.isabs(path):
                 self.cdata.set("paths", name, os.path.join(root, path))
 
     def setconfig(self, section, name, val):
@@ -208,7 +208,7 b' class ui(object):'
 
     def expandpath(self, loc, default=None):
         """Return repository location relative to cwd or from [paths]"""
-        if loc.find("://") != -1 or os.path.exists(loc):
+        if "://" in loc or os.path.exists(loc):
             return loc
 
         path = self.config("paths", loc)

mercurial/util.py

@@ -620,7 +620,7 b' else:'
     def parse_patch_output(output_line):
         """parses the output produced by patch and returns the file name"""
         pf = output_line[14:]
-        if pf.startswith("'") and pf.endswith("'") and pf.find(" ") >= 0:
+        if pf.startswith("'") and pf.endswith("'") and " " in pf:
             pf = pf[1:-1] # Remove the quotes
         return pf