perf: use locally defined revlog option list for Mercurial earlier than 3.7

perf: use locally defined revlog option list for Mercurial earlier than 3.7

Before this patch, referring commands.debugrevlogopts prevents perf.py
from being loaded by Mercurial earlier than 3.7 (or 5606f7d0d063),
because it isn't available in such Mercurial, even though
cmdutil.openrevlog(), a user of these options, has been available
since 1.9 (or a79fea6b3e77).

In addition to it, there are some code paths for Mercurial earlier
than 3.7. For example, setting "_prereadsize" attribute in perfindex()
and perfnodelookup() is effective only with hg earlier than 1.8 (or
61c9bc3da402).

But just "using locally defined revlog option list" might cause
unexpected behavior at runtime. If --dir option is specified to
cmdutil.openrevlog() of Mercurial earlier than 3.5 (or 49c583ca48c4),
it is silently ignored without any warning or so.

  ============ ============ ===== ===============
                                  debugrevlogopts
  hg version   openrevlog() --dir of commands
  ============ ============ ===== ===============
  3.7 or later     o          o         o
  3.5 or later     o          o         x
  1.9 or later     o          x         x
  earlier          x          x         x
  ============ ============ ===== ===============

Therefore, this patch does:

  - use locally defined option list, if commands.debugrevlogopts isn't
    available (for Mercurial earlier than 3.7)

  - wrap cmdutil.openrevlog(), if it is ambiguous whether
    cmdutil.openrevlog() can recognize --dir option correctly
    (for Mercurial earlier than 3.5)

    This wrapper function aborts execution, if:
    - --dir option is specified, and
    - localrepository doesn't have "dirlog" attribute, which indicates
      that localrepository has a function for '--dir'

    BTW, extensions.wrapfunction() has been available since 1.1 (or
    0ab5f21c390b), and this seems old enough for "historical
    portability" of perf.py, which has been available since 1.1 (or
    eb240755386d).

--- a/contrib/perf.py	Tue Jul 05 07:25:51 2016 +0900
+++ b/contrib/perf.py	Tue Jul 05 07:25:51 2016 +0900
@@ -30,6 +30,7 @@
     commands,
     copies,
     error,
+    extensions,
     mdiff,
     merge,
     obsolete,
@@ -48,7 +49,17 @@
 setattr(util, 'safehasattr', safehasattr)
 
 formatteropts = commands.formatteropts
-revlogopts = commands.debugrevlogopts
+
+# for "historical portability":
+# use locally defined option list, if debugrevlogopts isn't available,
+# because commands.debugrevlogopts has been available since 3.7 (or
+# 5606f7d0d063), even though cmdutil.openrevlog() has been available
+# since 1.9 (or a79fea6b3e77).
+revlogopts = getattr(commands, "debugrevlogopts", [
+        ('c', 'changelog', False, ('open changelog')),
+        ('m', 'manifest', False, ('open manifest')),
+        ('', 'dir', False, ('open directory manifest')),
+        ])
 
 cmdtable = {}
 command = cmdutil.command(cmdtable)
@@ -821,3 +832,18 @@
         timer, fm = gettimer(ui, opts)
         timer(fn, title=title)
         fm.end()
+
+def uisetup(ui):
+    if (util.safehasattr(cmdutil, 'openrevlog') and
+        not util.safehasattr(commands, 'debugrevlogopts')):
+        # for "historical portability":
+        # In this case, Mercurial should be 1.9 (or a79fea6b3e77) -
+        # 3.7 (or 5606f7d0d063). Therefore, '--dir' option for
+        # openrevlog() should cause failure, because it has been
+        # available since 3.5 (or 49c583ca48c4).
+        def openrevlog(orig, repo, cmd, file_, opts):
+            if opts.get('dir') and not util.safehasattr(repo, 'dirlog'):
+                raise error.Abort("This version doesn't support --dir option",
+                                  hint="use 3.5 or later")
+            return orig(repo, cmd, file_, opts)
+        extensions.wrapfunction(cmdutil, 'openrevlog', openrevlog)