But why would I get the warning if I build on Linux? The warning should
target the platform, not the entire build system.

You may use Linux to develop software that's intended to be used also on Mac and Windows. You can't expect developers to have build environment for every platform

That’s not a developer issue, it’s a packaging issue.

In D26752#596809, @tcanabrava wrote:

That’s not a developer issue, it’s a packaging issue.

AUTHOR_WARNING *is* for developers. If you want to hide these warnings, use -Wno-dev [1]

[1] https://cmake.org/cmake/help/latest/manual/cmake.1.html

I think we are misunderstanding eachother here.
If I'm developing the software and running cmake all the time, having a
warning that I can't fix (because it depends in another platform) is noise,
but still being a developer I don't want to run with -Wno-dev.
I do work in applications that targets more than one system (and they are
mac / windows / ios / android) I tend to use buildhosts, and those
buildhosts will tell me the warning - if any. But only if I'm targeting
them.

I don't see the gain on having a warning - in a windows system, about
missing mac icons if I'm not *deploying*.
nor I do see a warning on a linux system about windows or mac run time
issues (and missing icons is a run time issue).

In D26752#596949, @tcanabrava wrote:

I don't see the gain on having a warning - in a windows system, about
missing mac icons if I'm not *deploying*.

Then fix your code. ie only call ecm_add_app_icon on platforms you support (and leave the others broken, that's bad but you won't see the warning)

nor I do see a warning on a linux system about windows or mac run time
issues (and missing icons is a run time issue).

This is not a runtime issue. On Windows at least, the application icon is embedded in the executable.

These warnings are real issues.

Hi @cgiboudeaux and @bcooksley, there is a reason of why this patch is valid. Have you read the commit message ?

In Kirogi we provide a valid icon (svg) with a valid prefix (sc), as you probably know *sc* stands for for scalable (SVG) files.

As I said in the commit body, "KSVG2ICNS will not exist if the program is not being compiled to APPLE"
You'll probably say: "Well, so the developer should install this program."
Nops, if you take a look in kiconthemes: https://github.com/KDE/kiconthemes/blob/3e668c7fba9fda7469a75247e0926530cdd1eb29/src/CMakeLists.txt#L3
You'll see that KDE only provides such binary if APPLE is true.
Why such binary is important ? As you can see in ECMAddAppIcon: https://github.com/KDE/extra-cmake-modules/blob/master/modules/ECMAddAppIcon.cmake#L117
There is a APPLE check to convert the SVG binaries to mac valid icons.
Well, if KSVG2ICNS is only build to APPLE.
ECMAddAppIcon only looks for KSVG2ICNS with APPLE.
Why should ECMAddAppIcon provide such warning if KDE ECM andkiconthemes only do such thing for APPLE ?
There is no logic reason for this warning if everything else only works with APPLE.
If the developer wants to cross build for APPLE he should set APPLE and build everything to APPLE, this warning is still not valid with the logic present in this comment.
I did point using the code and the workflow of the ECM files why this patch is valid.

In D26752#597149, @patrickelectric wrote:

Hi @cgiboudeaux and @bcooksley, there is a reason of why this patch is valid. Have you read the commit message ?

In Kirogi we provide a valid icon (svg) with a valid prefix (sc), as you probably know *sc* stands for for scalable (SVG) files.

As expected, the problem is in the kirogi code. Read the ECMAddAppIcon doc:

# The given icons, whose names must match the pattern::
#
#   <size>-<other_text>.png

and now look at the kirogi code:

file(GLOB ICONS_SRCS "${CMAKE_CURRENT_SOURCE_DIR}/../data/icons/*apps-kirogi.svg")
ecm_add_app_icon(kirogi_SRCS ICONS ${ICONS_SRCS})

The warning about Windows is expected.

Now about Apple: if a .svg or .svgz is passed to ecm_add_app_icon, ksvg2icns (if found) will create the icons bundle.

The solution is not hiding the warning when the macro is called on different platform but fixing the condition.

Suggestion: After landing D26751, add a else() block to if (NOT (ext STREQUAL "svg" OR ext STREQUAL "svgz")) where you set(_ecm_add_app_icon_svg_icons TRUE)
and change:

if (NOT (mac_icons OR mac_sidebar_icons))

to:

if (NOT (mac_icons OR mac_sidebar_icons) AND NOT _ecm_add_app_icon_svg_icons)

Since ksvg2ico doesn't create the sidebar icons it can be further improved but at least you won't see a warning if you call ecm_add_app_icon with only svg files.

You will only get the warning about the broken behaviour on Windows.

Now another note: kirogi doesn't provide any png icon, this is also bad on Linux. Please create png icons and install them in the hicolor namespace.
See https://specifications.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html#install_icons

Hi @cgiboudeaux, thanks for the explanation, I'll take a look and get back here.