Forge 6.5.0 SDK won't install

[MultipleMonomials]

My users reported a crash bug in an ancient version of my mod (MC1.4.7, Forge 6.6.0.515) , but it's a version in active use in Tekkit Lite (?), so I'm trying to actually fix the issue.  I only became this mod's developer in MC 1.7.10, so I have very limited experience with the old Python-based build system.  I followed the standard instructions and ran install.cmd, but some of the patches failed to apply.  I fixed the compile errors and it recompiled the client, but it failed completely to decompile the server.  I tried with several 6.x and 6.5.x versions of forge, and the same thing happens. I realize that this is a legacy version, but I feel like it's a serious problem that the simplest use case fails for every old version.  Yes, I saw this thread, but this issue really deserves attention.  There is a good reason that we developers need the old SDKs to work. A log of the setup errors is here.  The important bit:

rc\minecraft\net\minecraft\client\renderer\entity\RenderPlayer.java:431: error: cannot find symbol
                for (var27 = 0; var27 < var21.getItem().getRenderPasses(var21.getItemDamage()); ++var27)
                                                                        ^

  symbol:   variable var21
  location: class RenderPlayer
src\minecraft\net\minecraft\client\renderer\entity\RenderPlayer.java:431: error: cannot find symbol
                for (var27 = 0; var27 < var21.getItem().getRenderPasses(var21.getItemDamage()); ++var27)
                                        ^

  symbol:   variable var21
  location: class RenderPlayer
src\minecraft\net\minecraft\src\ModLoader.java:638: warning: [deprecation] registerBlock(Block) in GameRegistry has been deprecated
        GameRegistry.registerBlock(block);
                    ^

src\minecraft\net\minecraft\src\ModLoader.java:649: warning: [deprecation] registerBlock(Block,Class<? extends ItemBlock>) in GameRegistry has been deprecated
        GameRegistry.registerBlock(block, itemclass);
                    ^

2 errors
10 warnings
==================

Client recompile failed, correct source then rerun updatemd5
=============================== Minecraft Forge Setup Finished =================================

<I fixed the compile errors manually.  It patched in var21 when it should have been var22>

updatemd5
== MCP 7.25 (data: 7.25, client: 1.4.6, server: 1.4.6) ==
WARNING:
The updatemd5 script is unsupported and should only be run in special
cases, such as if there were compile errors in the last decompile which
have now been corrected. It will reset the changed status of all classes
for reobfuscation, and only classes modified afterwards will end up in
the reobf directory.
Only use this script if you absolutely know what you are doing, or when a
MCP team member asks you to do so.
If you really want to update all classes, enter "Yes" yes
== Recompiling client ==
> Cleaning bin
> Recompiling
- Done in 19.15 seconds
> Generating client md5s
!! Can not find server sources, try decompiling !!

decompile
== MCP 7.25 (data: 7.25, client: 1.4.6, server: 1.4.6) ==
# found ff, ff patches, srgs, name csvs, doc csvs, param csvs, renumber csv, astyle, astyle config
> Creating Retroguard config files
!! Modified jar detected. Unpredictable results !!
!! client already decompiled. Run cleanup before decompiling again !!
!! Modified jar detected. Unpredictable results !!
== Decompiling server using fernflower ==
> Creating SRGs
> Applying Retroguard
'"C:\Program Files\Java\jdk1.8.0_66\bin\java" -cp "runtime\bin\retroguard.jar;lib;lib\*;jars\minecraf...' failed : 1

== ERRORS FOUND ==

Unrecoverable error during obfuscation, see log file for details.
RetroGuard error: COM.rl.obf.classfile.ClassFileException: ClassNotFound pl
==================

Decompile failed

 

This... should work, right?  It used to work!  What could have changed between now and a year or two ago that would make this fail?

 

EDIT 12/31/2016: The solution to this problem is to run MCP with Java 7.

[larsgerrits]

What? 1.4.7? That version is more than 3 years old! We don't provide help for any version besides the latest version [nobbc](1.[/nobbc] and the version before that (1.7).

 

If users are complaining about it, tell them they should move on to later versions. There's absolutely no reason the stay behing this far.