@infograf768 please don't re introduce the remove folder button. We can do this step automatically. I'll post some code in a bit

Try these:
default.php.v2.txt
remove.js.v2.txt

My understanding of what you want to do is, when version is Stable, to automatically delete the Installation folder as soon as one clicks on one of the buttons Complete and open ...

I tested your files without installing extra languages and setting version.php to stable
It does not work

Uncaught TypeError: document.querySelectorAll(...).map is not a function remove.js:33:56

I can’t work in rn but this or as is shouldn’t be merged as it messes up ux. You don’t need extra button for normal installations they are confusing just use the 2 existing ones

Setting this to WIP as the part concerning

Preventing installing languages after "installation" folder is deleted.
Display "Congratulations! Your Joomla site is ready." after installing and set languages after deleting installation folder.

is still correct.

@dgrammatiko

You don’t need extra button for normal installations they are confusing just use the 2 existing ones

I am sure you understand that this j4 installation code has been failing on many points since the beginning as it is extremely complex for little gain vs j3.
I am willing to help correct obvious bugs, but learning only at this stage that your original intention was to get rid of the "red" button when the version is stable is extremely frustrating as I have no crystal ball (understatement).

@infograf768 I haven't tested the change but look like there is a small bug in the propose code by @dgrammatiko. Could you please try to replace the code:

document.querySelectorAll('.removeInstallationFolder').map(function(el) {

with

[].slice.call(document.querySelectorAll('.removeInstallationFolder')).forEach(function (el) {

I think it will fix the error you mentioned.

@joomdonation
testing now.

works without installing languages :)
Now testing with languages and will modify my pr.

If version is stable, then It works, but if version is dev (even when not installing languages), the Remove installation folder button has no effect and I can't see any error in console.

Maybe we need to add back the old code as a supplement to the modified one to take care of that aspect?
What do you think?

I mean adding back this deleted part

-if (document.getElementById('removeInstallationFolder')) {
-	document.getElementById('removeInstallationFolder')
-		.addEventListener('click', function (e) {
-			e.preventDefault();
-			let confirm = window.confirm(Joomla.Text._('INSTL_REMOVE_INST_FOLDER').replace('%s', 'installation'));
-			if (confirm) {
-				Joomla.request({
-					method: "POST",
-					url: Joomla.installationBaseUrl + '?task=installation.removeFolder&format=json',
-					perform: true,
-					token: true,
-					headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
-					onSuccess: function () {
-						const customInstallation = document.getElementById('customInstallation');
-						customInstallation.parentNode.removeChild(customInstallation);
-						const removeInstallationTab = document.getElementById('removeInstallationTab');
-						removeInstallationTab.parentNode.removeChild(removeInstallationTab);
-					},
-					onError: function (xhr) {
-            Joomla.renderMessages({ error: [xhr] }, '#system-message-container');
-					}
-					}
-				);
-			}
-		}
-		);
-}

EDIT:
in fact looks like new code is confusing as it uses
if (e.target.dataset.isDev) { return; }

It works if I do

[].slice.call(document.querySelectorAll('.removeInstallationFolder')).forEach(function (el) {
  el.addEventListener('click', function (e) {
      e.preventDefault();
      // We skip removing data for dev setups on the redirect buttons, unless someone clicks on the extra red button
      if (e.target.dataset.isDev) {
      	let confirm = window.confirm(Joomla.Text._('INSTL_REMOVE_INST_FOLDER').replace('%s', 'installation'));
      	if (confirm) {
      		Joomla.request({
					method: "POST",
					url: Joomla.installationBaseUrl + '?task=installation.removeFolder&format=json',
					perform: true,
					token: true,
					headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
					onSuccess: function () {
						const customInstallation = document.getElementById('customInstallation');
						customInstallation.parentNode.removeChild(customInstallation);
						const removeInstallationTab = document.getElementById('removeInstallationTab');
						removeInstallationTab.parentNode.removeChild(removeInstallationTab);
					},
					onError: function (xhr) {
						Joomla.renderMessages({ error: [xhr] }, '#system-message-container');
					}
					}
				);
			}
		 } else {
        Joomla.request({
            method: "POST",
            url: Joomla.installationBaseUrl + '?task=installation.removeFolder&format=json',
            perform: true,
            token: true,
            headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
            onSuccess: function () {
              const customInstallation = document.getElementById('customInstallation');
              customInstallation.parentNode.removeChild(customInstallation);
              const removeInstallationTab = document.getElementById('removeInstallationTab');
              removeInstallationTab.parentNode.removeChild(removeInstallationTab);
              window.location.href = e.target.dataset.redirectTo;
            },
            onError: function (xhr) {
              Joomla.renderMessages({ error: [xhr] }, '#system-message-container');
            }
          }
        );
      }
    }
  );
});

@joomdonation @dgrammatiko

Are you OK with this? If yes I can correct tabs/dots and other cs and modify my PR or make a new one.

@infograf768 You don't need the extra if/lse with the same code could be :

[].slice.call(document.querySelectorAll('.removeInstallationFolder')).forEach(function (el) {
  el.addEventListener('click', function (e) {
      e.preventDefault();
        Joomla.request({
            method: "POST",
            url: Joomla.installationBaseUrl + '?task=installation.removeFolder&format=json',
            perform: true,
            token: true,
            headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
            onSuccess: function () {
              const customInstallation = document.getElementById('customInstallation');
              customInstallation.parentNode.removeChild(customInstallation);
              const removeInstallationTab = document.getElementById('removeInstallationTab');
              removeInstallationTab.parentNode.removeChild(removeInstallationTab);
      // We skip removing data for dev setups on the redirect buttons, unless someone clicks on the extra red button
              let confirm =(e.target.dataset.isDev) ? window.confirm(Joomla.Text._('INSTL_REMOVE_INST_FOLDER').replace('%s', 'installation')) : undefined;
              if (!confirm) { window.location.href = e.target.dataset.redirectTo; }
            },
            onError: function (xhr) {
              Joomla.renderMessages({ error: [xhr] }, '#system-message-container');
            }
      });
    }
  });
});

Uncaught SyntaxError: missing ) after argument list 56:2

here is line 56

@infograf768 my bad remove the } on line 55

not there yet.
Status: development
The alert is displayed after clicking on the Complete & Open... when not using the delete folder button although the installation folder is already deleted.

html code is

Also, if I use the Remove folder button and then click on cancel, it deletes the installation and open admin login...

Also, if I use the Remove folder button and then click on cancel, it deletes the installation and open admin login...

Where is this cancel button?

html code is

			<div class="alert flex-column mb-1" id="removeInstallationTab">
				<?php if ($this->development) : ?>
					<span class="mb-1 font-weight-bold"><?php echo Text::sprintf('INSTL_SITE_DEVMODE_LABEL', 'installation'); ?></span>
					<button class="btn btn-danger mb-1 removeInstallationFolder" data-is-dev="false" data-redirect-to="<?php echo Uri::root(); ?>administrator"><?php echo Text::sprintf('INSTL_COMPLETE_REMOVE_FOLDER', 'installation'); ?></button>
				<?php endif; ?>
			</div>
			<?php echo HTMLHelper::_('form.token'); ?>

			<div class="form-group j-install-last-step d-grid gap-2">
				<button class="btn btn-primary w-100 removeInstallationFolder" data-is-dev="<?php echo (bool) $this->development; ?>" data-redirect-to="<?php echo Uri::root(); ?>"><span class="icon-eye" aria-hidden="true"></span> <?php echo Text::_('INSTL_COMPLETE_SITE_BTN'); ?></button>
				<button class="btn btn-primary w-100 removeInstallationFolder" data-is-dev="<?php echo (bool) $this->development; ?>" data-redirect-to="<?php echo Uri::root(); ?>administrator"><span class="icon-lock" aria-hidden="true"></span> <?php echo Text::_('INSTL_COMPLETE_ADMIN_BTN'); ?></button>
			</div>

The js alert to confirm deleting the folder

Why do you get an alert in the first place? This seems wrong

can you add console.log(xhr) and share the data? You shouldn't have an error there

INSTL_REMOVE_INST_FOLDER="Are you sure you want to delete? Confirming will permanently delete the \"%s\" folder."

where do you want me to add console.log(xhr)?

No result using
console.log(xhr);
Installation folder is immediately deleted before clicking on OK. Evidently Cancel is no use.

@infograf768 who added this confirm thing? This is totally wrong

Edit: I see, you did that, please remove it. You don't have to ask, the installation folder NEEDS to be removed on the normal installations and for devs there's an extra button saying Remove Installation folder. It's obvious what will happen if you press the button no need for confirmation. Please don't add friction on the UX, do what needs to be done with sensible defaults

Edit: I see, you did that, please remove it.

You are joking I hope!! It was you, before and after your proposal above.

and it was there before you posted
#32601 (comment)

and it was working before as you deleted the old code

-if (document.getElementById('removeInstallationFolder')) {
-	document.getElementById('removeInstallationFolder')
-		.addEventListener('click', function (e) {
-			e.preventDefault();
-			let confirm = window.confirm(Joomla.Text._('INSTL_REMOVE_INST_FOLDER').replace('%s', 'installation'));
-			if (confirm) {
-				Joomla.request({
-					method: "POST",
-					url: Joomla.installationBaseUrl + '?task=installation.removeFolder&format=json',
-					perform: true,
-					token: true,
-					headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
-					onSuccess: function () {
-						const customInstallation = document.getElementById('customInstallation');
-						customInstallation.parentNode.removeChild(customInstallation);
-						const removeInstallationTab = document.getElementById('removeInstallationTab');
-						removeInstallationTab.parentNode.removeChild(removeInstallationTab);
-					},
-					onError: function (xhr) {
-            Joomla.renderMessages({ error: [xhr] }, '#system-message-container');
-					}
-					}
-				);
-			}
-		}
-		);
-}

I just copy/pasted the thing you provided that was repeating 20 lines of code for no reason. I didn't really process your code!!!

This is what we have now in 4.0-dev. No comment. it is obvioulsy NOT my code.

Correct, also it was you that introduced this crap: 7162ed4

Please remove it, you're adding friction whenever you ask users anything. Just do the right thing, by default! Also for dev env, you don't even need a button, just say Hey you're on dev, we are no deleting the installation folder. There's no dev out there that cannot delete a folder manually if they need to (although if you're in dev mode you never need to do so). In short, you're massively complicating what should be a straight forward behaviour

What I added concerned the string itself and has no impact on your failing code. That's where is the main "crap" as you nicely say.
The button is very useful for people who test on remote. I guess that's the reason you added it originally.
I close this PR as obviously the installation code is a full failure. I quit trying to help on this.

Do we need an issue for the remaining things? As I remember we had only a comment in #32516 .

@richard67 Just look at the description of this PR and you will see what I tried to correct., specially the part concerning the languages.

@infograf768 Instead of closing the PR, maybe leave it as how it is and let us know the bugs which need to be fixed so that we can try to get it sorted?

The button is very useful for people who test on remote. I guess that's the reason you added it originally.

@infograf768 I never implemented the removal of the installation, it was done here: #26276

So I apologise for the crap as it wasn't really you!

That said the whole concept I had for the installation was simplification, ask only what needs to be answered. The way the removal of the installation was implemented is totally against that idea and frankly unacceptable. You don;t need to ask obvious things...

There is no major bug in the PR itself except the will to suddenly change the way to delete the installation folder directly using the "complete & open...' buttons when version is stable.
In that case, as it modifies the js drastically and we still have a Delete folder button to obviously add security when people test on remote, the proposal above #32601 (comment) (corrected) just fails and its failure prevents the other stuff I was trying to solve to be solved.

I totally disagree with the statement "You don't need to ask obvious things..."
It is only obvious for matured code people.

It is only obvious for matured code people.

A dev using the git version of Joomla needs to answer a question if they are sure that they want to delete the installation folder?

Well, obviously, we see the world from different lenses

We do NOT have only matured devs testing. Many testers use the patched ready to go install pack provided when a PR is ready. These people do not use git or ide.

These people do not use git or ide.

Even so, what are the expectation when clicking on the button Remove Installation Folder? To order coffee from Starbucks?
Let's be realistic here, a red BIG button with a very clearly defined message is enough. Anyways since this thing is only affecting the dev I guess you can make their life more miserable by asking one more question. Do it your way

@dgrammatiko Please remember that you are debating with someone who believes that.... Oh forget it. Not worth the aggro

Relax there is a lot of stress because it is urgent to launch Joomla 4, it is years behind schedule and the worst thing is that the community is weakening because it already seems like a utopia to think that it will be released.
The worst mistake has been the philosophy of saying it will be ready when it is ready. People are abandoning the project.
If the basics are released people will quickly switch to Joomla 4 and cheer up or contribute or else Joomla could become a wasteland.

@Quy
afaik, this is still a release blocker as no solution is provided when installing a non-beta version and we still have issue concerning preventing installing languages after "installation" folder is deleted. Thus why @wilsonge tagged it as release blocker.

@infograf768 I assume that @Quy removed the release blocker tag because this is closed. Probably best to create a new issue outlining the problems (again) and then tagging that as a release blocker.

(far too many release blockers have simply been resolved by removing the tag ? )