I'm not a friend of creating a bunch of empty folders if I explicitly don't need them or don't want them. Simply remove the tag <inheritable>0</inheritable> in your manifest.

References:
#39329
But has been reverted: #39943

2. Question:
   If your solution is accepted. Will these folders automatically removed on uninstallation of the child template?

Install a child template without any media files.

This is not supported by Joomla, Joomla's own functionality WILL NEVER create a child without the expected folders. Instead of trying to bend Joomla to your way why not align your way to the Joomla's expectations?

1. Agree with empty folder comment.
   Don't know why relevant.

2. As I mentioned in the related issue, this may not be relevant in 'the real world'!

I suppose when removing 'mytemplate', for completness, the installer should remove everything in the following places regardless of what the manifest XML says ... it may already do that, I have not investigated!

templates/mytemplate
media/templates/site/mytemplate
language//mytemplate.ini
language//mytemplate.sys.ini

There might be other areas to which a similar installer 'for completeness' comment might apply!

Then why does Joomla allow me to install a template without media files?

Surely the template media files will only be relevant to the template or other template related extensions. That's an issue for template / extension developers to address.

Joomla should just allow the situation without confusing messages during template testing / development.

Also if you must do the magic creation either do it in the install or discover on the installer adapter:

I'm not a fan of code that does something different than what is defined in the XML...

Joomla should just allow the situation without confusing messages during template testing / development.

absolutely not. its not a confusing message it is the 100% correct message.

I agree a change to the installer adapter would avoid this situation happening - and would need further investigation.
This change addresses the situation after it has happened in a dev / test environment.

This change provides a safe display of an empty media location to which the admin can then add folders / files in the usual manner.

A better way might be to create an empty index.html file in that location - but that does not solve the problem as index.html is not a media file! See functions getDirectoryTree() and checkFormat() ... would need an empty file called 'empty.jpg' or similar.

Just discovered that if admin deletes all items under media/templates/site/mytemplate there is no way they can add something. They have to add what they want and then delete what they don't want! My solution solves that problem, although they may not want the css, images, js and sccs folders I created ,,, they still have to create what they want and delete what I created! At least they can create them.

The message has not changed. The code change only avoids the message when it is unnecessary.

This change addresses the situation after it has happened in a dev / test environment.

Again: Joomla's own functionality produces child templates with the expected structure. To get to a point where the structure is not the expected you, probably, tried to manually create a child but missed the media folders. Joomla is not broken.

This change provides a safe display of an empty media location to which the admin can then add folders / files in the usual manner.

Sorry this is kinda unacceptable (imho), the templates file manager is not supposed to correct faulty XML definitions, separation of concerns.

Maybe https://github.com/dgrammatiko/mod_child_export will help your situation (?).The way you produce the installable child templates is quite crucial!

This is not a faulty XML definition.
It is a valid child template manifest.

It is a valid child template manifest.

Can you post the XML?

BTW, the <media> section is required, so are the media folders. ie: Joomla will never create a child without the media section in the XML or missing the folders...

Refer to pull request #40665

Refer to pull request #40665

You know what? Enough time wasted here, do whatever you want. Unsubscribing

I agree with the above concerns that this PR is not the right way. But let's see if other opinions come it.

Better idea occurred to me avoiding the creation of dummy css, images, js and sccs folders. Appears to solve the problem and allows the site admin to add files / folders as needed.

The only correct fix as stated before is to include the media folders.

That implies that the installer needs to be changed so that it either:
(a) It prevents attempts to install a template without a media section in the manifest. But what if there is no media content? Maybe unlikely but sounds to me like this places an unnecessary restriction on template developers. Anyway there is currently nothing to prevent a site admin using the 'Templates: Customise' page to manually remove all template media content.
or (b) If there is no media section in the manifest it creates the folder media/templates/site/tpl_mytemplate anyway.

In both cases the changes in this pull request serve 3 useful purposes which obviate the need for the above installer changes.
(1) On entry to the 'Templates: Customise' page ensures the media/templates/site/tpl_mytemplate folder exists anyway.
(2) If the media/templates/site/tpl_mytemplate folder is empty (missing in manifest or otherwise purged in some way) allows the site admin to use the 'Templates: Customise' page to see that it is empty and (re-)add folders and files as required.
(3) Only display the non-writtable warning if the media/templates/site/tpl_mytemplate folder is genuinely non-writtable. Currently the message is displayed if the folder does not exist, which is confusing - being non-writtable and missing are not the same thing!

Thanks for your contribution.
But as already explained, you have to provide everything Joomla needs on installation and add it to the manifest.

I'm closing this since it does unexpected magic from my point of view. You can always open it again if you think it's needed.