doxygen x_noenv should always diff system-dependent settings

[ferdymercury]

Describe the bug
There are some settings in the Doxyfile that are system-dependent, like CASE_SENSE_NAMES. These are not properly identified when x_noenv is run.

Expected behavior
When doxygen -x_noenv is run, it should always print these values, whatever its value, as one is assuming no environment (in a broad sense, one does not want to be system-dependent). Or maybe print them under special section with asterisks, with a footnote that this might be a "system dependent diff".

The alternative would be that the default value of all variables are made always the same for all systems.

To Reproduce

doxygen -g
doxygen -x_noenv
CASE_SENSE_NAMES should appear there as 'diff'

Version
Doxyfile 1.9.4 (91095fb*)

Additional context
root-project/root#9966

[albert-github]

You wrote:

There are some settings in the Doxyfile that are system-dependent

Besides the CASE_SENSE_NAMES which other ones did you identify? I could only find the CASE_SENSE_NAMES.
Other system dependent values like NUM_PROC_THREADS are / should be "protected" by a 0 value (as the minval).

For the boolean value of CASE_SENSE_NAMES this is not possible as we have here only 2 possible values (false and true) and nothing to use as a flag. Furthermore the determination of the value to be used is set, by means of a function call, during the initialization of the config structure (though at that moment the value of the option is known). The mean problem remains that the bool value only has 2 possibilities, maybe we have to switch here as well to an enum value with the values NO, YES and SYSTEM, where SYSTEM determines the value at runtime.
(Note the current defval has no real meaning here as always the function is called).

[ferdymercury]

Besides the CASE_SENSE_NAMES which other ones did you identify? I could only find the CASE_SENSE_NAMES.

True, there is only this one.

For the boolean value of CASE_SENSE_NAMES this is not possible as we have here only 2 possible values

I think I did not explain it clearly. What I meant is that, when you run doxygen -x_noenv, it should always show the CASE_SENSE_NAMES boolean stored in the Doxyfile. Independently on whether its stored value matches or not the system-dependent default-value. To ensure that if I make a diff on Macos in a PR and you try it on Linux, we are using the same value, YES or NO. Otherwise, if I do not specify in my Doxyfile any CASE_SENSE_NAMES, we would be running our 'tests' effectively with different settings.

[ferdymercury]

To give an example, in our ROOT Doxyfile, we had CASE_SENSE_NAMES set to yes. When I run doxygen -x_noenv in Linux, it didn't appear in the diff, as it was thought to be the default value. Thus I wrote another Doxyfile only specifying the non-default values. Now I moved to macOS, and because its default value for this variable is different, doxygen was running with different settings. Thus, I think that:

• if CASE_SENSE_NAMES is defined in the Doxyfile, it should always print its value in the -x_noenv version
• if not defined, then it should not

I'd say we do not need a third SYSTEM option, as this would be the same as "leaving it out" of the Doxyfile ?

[albert-github]

The MacOS and Linux have different defaults (as far as I can see)
Form portable.cpp:

bool Portable::fileSystemIsCaseSensitive()
{
#if defined(_WIN32) || defined(macintosh) || defined(__MACOSX__) || defined(__APPLE__) || defined(__CYGWIN__)
  return FALSE;
#else
  return TRUE;
#endif
}

so for MacOS the default is FALSE (NO) and for Linux the default is TRUE (YES).

It might be that these definitions are outdated and the MacOS is case sensitive as well (like Linux).
In case MacOS is case sensitive now we might need to improve the default setting here.

Regarding:

if CASE_SENSE_NAMES is defined in the Doxyfile, it should always print its value in the -x_noenv version
if not defined, then it should not

this will be difficult as at the moment of printing it is not known anymore whether or not the value was in the used doxygen settings file or not.

[ferdymercury]

In case MacOS is case sensitive now we might need to improve the default setting here.

Sounds good.

this will be difficult as at the moment of printing it is not known anymore whether or not the value was in the used doxygen settings file or not.

oh, I see.

[albert-github]

Is MacOS currently case sensitive (I cannot test this as I don't have access to any MacOS system).

[ferdymercury]

I don't have access to it either. But I checked online and it seems it's by default not case sensitive, but it can be configured to be. So maybe the default doxygen setting should indeed not be changed.

[albert-github]

@doxygen what is your opinion?

(From: https://stackoverflow.com/a/56601467/1657886
One system can have multiple file systems, where some are case sensitive and some are not. )

[albert-github]

I've just pushed a proposed patch, pull request #9526

[ferdymercury]

Thanks!!

[albert-github]

Code has been integrated in master on GitHub (please don't close the issue as this will be done at the moment of an official release).