On Mon, 2 Feb 2026 14:41:35 GMT, Erik Joelsson <[email protected]> wrote:

>> Allow conversion warnings in subsets of the code base. By allowing this, we 
>> can improve the code base in parts, and see that those parts do not regress 
>> in the future.
>> 
>> My approach to implement this is by adding support to our make system to 
>> recognise and handle "variable packs". A "variable pack" is a list of quoted 
>> variable "appendings". It will be picked up by `NamedParamsMacroTemplate` 
>> and there recognised by the lack of an assignment operator that is always 
>> used when sending variables to macros today. To support sending lists of 
>> "variable appendings", the appendings must quote assignment, spaces and 
>> quotes. This would be cleanest to implement by hex or base64 encode the 
>> string. However, this is extremely hard to do in make, and I prefer not 
>> calling the likes of `od` or `base64` to make the code portable and fast.
>> 
>> With this infrastructure I implement a simple recursive utility to find all 
>> files matching a pattern in a folder; I then transform that list to variable 
>> assignments that will add compiler warnings for those files.
>> 
>> This approach is extremely flexible. I can for example combine many calls to 
>> the `overrideFlags` macro with different source directories and different 
>> patterns.
>> 
>> The macro will expand to something like (depending on compiler): 
>> `module_file1.cpp_CXXFLAGS+=-Wconversion`
>> `module_file2.cpp_CXXFLAGS+=-Wconversion`
>> 
>> this can flexibly be combined with other flags to overlap: 
>> `module_file2.cpp_CXXFLAGS+=$(SPACE)-Wotherflag`
>> `module_file3.cpp_CXXFLAGS+=$(SPACE)-Wotherflag`
>> 
>> (note the overlapping sets of flags `file1 -Wconversion`, `file2 
>> -Wconversion -Wotherflag`, `file3 -Wotherflag`)
>
> make/common/MakeBase.gmk line 144:
> 
>> 142: $(eval $(call SetupLogging))
>> 143: 
>> 144: 
>> ################################################################################
> 
> Could you add a description of what this section tries to do and how to use 
> it here? Something similar to the PR comment.

Yes.

> make/common/MakeBase.gmk line 180:
> 
>> 178: 
>> 179: # $(call overrideFlags,dir,%.cpp,_CXXFLAGS,-Wconversion) -> 
>> file1.cpp_CXXFLAGS#+-Wconversion file2.cpp_CXXFLAGS#+-Wconversion
>> 180: overrideFlags = $(foreach file,$(call filterFiles,$1,$2,),$(call 
>> quoteAppend,$(file)$3,$4))
> 
> I think this is the only macro here that is meant to be called by users. It 
> would help if you could move it to either the top or the bottom and give it a 
> proper description on now it is expected to be used.

I will do so. I think `quoteAppend` might also be useful as a general way to 
send "variable packs" or "varargs" and possibly used by others.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/29523#discussion_r2755409462
PR Review Comment: https://git.openjdk.org/jdk/pull/29523#discussion_r2755405721

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