[PATCH 1 of 8] debugrevlog: document some of the variable used

[Boris Feld]

# HG changeset patch
# User Boris Feld <boris.feld at octobus.net>
# Date 1532681999 -7200
#      Fri Jul 27 10:59:59 2018 +0200
# Node ID 370c3f5021dedb80ded496d39f76f73facd6b7d3
# Parent  d99468d2b09acc8f5c6c5ce5c1b08b47a742841f
# EXP-Topic sparse-snapshot
# Available At https://bitbucket.org/octobus/mercurial-devel/
#              hg pull https://bitbucket.org/octobus/mercurial-devel/ -r 370c3f5021de
debugrevlog: document some of the variable used

This help to understand the code.

diff --git a/mercurial/debugcommands.py b/mercurial/debugcommands.py
--- a/mercurial/debugcommands.py
+++ b/mercurial/debugcommands.py
@@ -2083,18 +2083,30 @@ def debugrevlog(ui, repo, file_=None, **
     if not flags:
         flags = ['(none)']
 
+    ### tracks merge vs single parent
     nummerges = 0
+
+    ### tracks ways the "delta" are build
+    # full file content
     numfull = 0
+    # delta against previous revision
     numprev = 0
+    # delta against first or second parent (not prev)
     nump1 = 0
     nump2 = 0
+    # delta against neither prev nor parents
     numother = 0
+    # delta against prev that are also first or second parent
+    # (details of `numprev`)
     nump1prev = 0
     nump2prev = 0
+
+    # data about delta chain of each revs
     chainlengths = []
     chainbases = []
     chainspans = []
 
+    # data about each revision
     datasize = [None, 0, 0]
     fullsize = [None, 0, 0]
     deltasize = [None, 0, 0]