simple mercurial tricks

[Tom Rodriguez]

I just figured out a couple simple mercurial tricks that I thought I'd  
share.  The first is using the mercurial tags to figure out which  
hotspot build went into a particular jdk build.  The basic form is this:

hg cat -r tag make/hotspot_version | grep HS_

where tag is one of the jdk7-b* tags that RE puts on the build.  For  
instance

% hg cat -r jdk7-b39 make/hotspot_version | grep HS_
HS_MAJOR_VER=14
HS_MINOR_VER=0
HS_BUILD_NUMBER=06

So jdk7-b39 has hs14.0-b06 in it.

You can do something similar with the web interface using URLs like  
this:

http://hg.openjdk.java.net/jdk7/hotspot/hotspot/file/jdk7-b39/make/hotspot_version

Obviously the hotspot_version file contents are only meaningful at the  
pointer the promotion was made so you can't get a direct mapping from  
a changeset to the particular build it went into.

The other trick requires a mercurial extension called nearest from http://freehg.org/u/morisgi/nearest 
. Basically it finds the immediately dominating tag for a particular  
revision.  It can also find the post dominating tag, which lets you  
directly query which jdk build a particular fix went into.

% hg log -r 8261ee795323
changeset:   333:8261ee795323
user:        rasbold
date:        Wed Sep 17 08:29:17 2008 -0700
summary:     6711100: 64bit fastdebug server vm crashes with  
assert(_base == Int,"Not an Int")

% hg nearest --contains  
8261ee795323 
                                                                              jdk7 
-b39-21

So 8261ee795323 is 21 changesets before the changeset tagged with jdk7- 
b39, so 6711100 was fixed in hs14-b06 which is in jdk7-b39.  There are  
other ways to find the answer to these questions but I think asking  
the repo directly is more reliable and often more convenient.  I've  
only played with the nearest extensions lightly but I didn't see any  
way to ask this question with existing commands and it seems to work ok.

tom