RFR: 8066821(S) Enhance command line processing to manage deprecating and obsoleting -XX command line arguments

[Karen Kinnear]

Derek,

Many thanks for the latest changes. And thank you for the verify_special_jvm_flags -- that will remind us to
clean up the flags when the version number changes. So the expired_in information is for internal use only - we
don't print that information for users, we simply tell them "in a future release".

Looks good. No need for my further code review.

Minor comments:
1. arguments.hpp
line 421 "In the case" -> "In this case"

2. arguments.cpp comments

I love the high level comments - could you possibly update them?
   - e.g. they still talk about the deprecated_jvm_flags and obsolete_jvm_flags tables.
   - e.g. expired and obsolete options should have their global variable definitions and
     related implementations removed ...

comment line 2119 - extra spaces at the front? (or webrev artifact?)

thanks very much,
Karen




On Aug 24, 2015, at 1:27 PM, Derek White wrote:

> RFR:
> 
> This version incorporates Dave and Karen's suggestions to automatically handle deprecated-> obsolete transitions. This is implemented with a unified table of deprecated and obsolete options ("special_jvm_flags").
> 
> Karen also suggested (offline) that it would be good to verify that obsolete and expired options no longer have a "globals" variable defined. This revision adds debug checking of the special_jvm_flags table to check a bunch of constraints, such as deprecated version must be < obsolete version < expired version, and checks for duplicate table entries as well as looking for left-over "globals" variables.
> 
> http://cr.openjdk.java.net/~drwhite/8066821/webrev.08
> https://bugs.openjdk.java.net/browse/JDK-8066821
> 
> I also have a webrev of webrev.07 vs. webrev.08:
> http://cr.openjdk.java.net/~drwhite/8066821/webrev.7.v.8
> 
> Thanks for looking!
> 
> - Derek
> 
> On 8/11/15 3:33 PM, Derek White wrote:
>> Hi Karen,
>> 
>> As much as I want to get this RFE over and out, I see your and David H's point :-)
>> 
>> I'll spin another rev...
>> 
>> - Derek
>> 
>> On 8/10/15 6:07 PM, Karen Kinnear wrote:
>>> Derek,
>>> 
>>> Thank you for all of your work on this and responses to suggestions.
>>> 
>>> I had a couple of questions/comments:
>>> 
>>> I appreciate that you have created mechanisms to allow:
>>> 1. 2 step obsolete: obsolete_jvm_flags
>>>     - step 1: obsolete: warn and ignore
>>>     - step 2: expire
>>>     - and I expect we will use this for most -XX flags, especially develop flags
>>> 
>>> 2. 2 step deprecate: deprecated_jvm_flags
>>>     - step 1: deprecate: warn and handle
>>>     - step 2: expire
>>> 
>>> I see this approach as useful for aliasing and for a few other flags, but not
>>> the common path.
>>> 
>>> My concerns:
>>> 
>>> With my understanding of how this is set up today, for the flags that are most exposed to
>>> customers, which would want the 3 step deprecation, it would be too easy for an engineer
>>> to add the flag to the deprecated_jvm_flags and forget to add it to the obsolete_jvm_flags,
>>> as the comments under deprecated_jvm_flags suggest.  And we don't want folks to have
>>> to go back and do a second step later for flags if they could do it all at once.
>>> 
>>> I think it would be confusing to add a flag to both deprecated_jvm_flags and obsolete_jvm_flags
>>> at the same time, since then the expiration release is not clear.
>>> 
>>> 3. For product non-XX, commercial and common -XX flags what I would like to see is
>>> a three-step table which I would have called deprecated_jvm_flags, which did
>>>     - step 1: deprecate: warn and handle
>>>     - step 2: obsolete: warn and ignore
>>>     - step 3: expire: unrecognized error
>>> 
>>> Would you be willing to add a table like that which is the recommended approach
>>> for external supported flags?
>>> 
>>> So one way to do this would be to change the current deprecated_jvm_flags to have
>>> three fields, so that the usual path would be to have three releases listed, and
>>> for aliased flags leave the middle field with the undefined version.
>>> 
>>> Another approach would be to have the three fields and have it used by
>>> all three approaches, just fill in the steps that are appropriate.
>>> 
>>> minor comment:
>>> 
>>> 
>>> 1. arguments.hpp
>>> Could you possibly change the comments from "and has expired (should be ignored)" to
>>> "and has expired (unrecognized error)"
>>> 
>>> unless what you mean really is should be ignored, which is not the same expired.
>>> 
>>> thanks,
>>> Karen
>>> 
>>> 
>>> 
>>> On Aug 10, 2015, at 12:41 PM, Derek White wrote:
>>> 
>>>> Thanks David!
>>>> 
>>>> - Derek
>>>> 
>>>> On 8/10/15 1:53 AM, David Holmes wrote:
>>>>> Hi Derek,
>>>>> 
>>>>> I don't have any further comments.
>>>>> 
>>>>> Thanks,
>>>>> David
>>>>> 
>>>>> On 7/08/2015 12:46 PM, Derek White wrote:
>>>>>> Another RFR.
>>>>>> 
>>>>>> I've updated based on David and Kim's last comments.
>>>>>> 
>>>>>> http://cr.openjdk.java.net/~drwhite/8066821/webrev.07/
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8066821
>>>>>> 
>>>>>> I also have a webrev of webrev.06 vs. webrev.07:
>>>>>> http://cr.openjdk.java.net/~drwhite/8066821/webrev.6.v.7/
>>>>>> 
>>>>>> [This webrev is confused about CommandLineOptionTest.java. I
>>>>>> double-checked with a recursive diff and the only differences are in
>>>>>> arguments.cpp and arguments.hpp.]
>>>>>> 
>>>>>> Thanks for looking!
>>>>>> 
>>>>>>  - Derek
>>>>>> ....
>> 
>