check-commit: support REVs as commandline arguments

usage:
* HG_NODE=REV check-commit
* hg export REV | check-commit
* check-commit REV ...

contrib/check-commit

@@ -1,66 +1,74 b''
 #!/usr/bin/env python
 #
 # Copyright 2014 Matt Mackall <[e-mail]>
 #
 # A tool/hook to run basic sanity checks on commits/patches for
 # submission to Mercurial. Install by adding the following to your
 # .hg/hgrc:
 #
 # [hooks]
 # pretxncommit = contrib/check-commit
 #
 # The hook can be temporarily bypassed with:
 #
 # $ BYPASS= hg commit
 #
 # See also: https://mercurial-scm.org/wiki/ContributingChanges
 
 import re, sys, os
 
 errors = [
     (r"[(]bc[)]", "(BC) needs to be uppercase"),
     (r"[(]issue \d\d\d", "no space allowed between issue and number"),
     (r"[(]bug(\d|\s)", "use (issueDDDD) instead of bug"),
     (r"^# User [^@\n]+$", "username is not an email address"),
     (r"^# .*\n(?!merge with )[^#]\S+[^:] ",
      "summary line doesn't start with 'topic: '"),
     (r"^# .*\n[A-Z][a-z]\S+", "don't capitalize summary lines"),
     (r"^# .*\n[^\n]*: *[A-Z][a-z]\S+", "don't capitalize summary lines"),
     (r"^# [^\n]*\n\S*[^A-Za-z0-9-]\S*: ",
      "summary keyword should be most user-relevant one-word command or topic"),
     (r"^# .*\n.*\.\s+$", "don't add trailing period on summary line"),
     (r"^# .*\n[^#].{78,}", "summary line too long (limit is 78)"),
     (r"^\+\n \n", "adds double empty line"),
     (r"^ \n\+\n", "adds double empty line"),
     (r"^\+[ \t]+def [a-z]+_[a-z]", "adds a function with foo_bar naming"),
 ]
 
-def checkcommit(commit):
+def checkcommit(commit, node = None):
     exitcode = 0
+    printed = node is None
     for exp, msg in errors:
         m = re.search(exp, commit, re.MULTILINE)
         if m:
             pos = 0
             for n, l in enumerate(commit.splitlines(True)):
                 pos += len(l)
                 if pos >= m.end():
+                    if not printed:
+                        printed = True
+                        print "node: %s" % node
                     print "%d: %s" % (n, msg)
                     print " %s" % l[:-1]
                     if "BYPASS" not in os.environ:
                         exitcode = 1
                     break
     return exitcode
 
 def readcommit(node):
     return os.popen("hg export %s" % node).read()
 
 if __name__ == "__main__":
+    exitcode = 0
     node = os.environ.get("HG_NODE")
 
     if node:
         commit = readcommit(node)
+        exitcode = checkcommit(commit)
+    elif sys.argv[1:]:
+        for node in sys.argv[1:]:
+            exitcode |= checkcommit(readcommit(node), node)
     else:
         commit = sys.stdin.read()
-
-    exitcode = checkcommit(commit)
+        exitcode = checkcommit(commit)
     sys.exit(exitcode)