Move from go get to git clone for fyne get

[andydotxyz]

This clearly belongs on the new repo - but first I wanted to land it here to pick onto the release branch for quicker fix :)

Fixes #4684

Checklist:

• Tests included.
• Lint and formatter run with no errors.
• Tests all pass.

[Jacalz]

See note inline about importing a deprecated package. Maybe there is something better we can use?

[Jacalz]

This does not seem to clean up the temporary directory after installation. Trying to install twice (because I got an error the first time) results in this:

fatal: destination path '/tmp/v3' already exists and is not an empty directory.
exit status 128

I think you are missing a defer os.Remove() or similar.

I am not sure if this is due to this PR or not (my Go install did apparently not work at all with fyne get before this change) but I'm getting this error when trying to install Rymdport (fyne_demo works fine):

$ fyne get github.com/Jacalz/rymdport/v3

Cloning into '/tmp/v3'...
remote: Enumerating objects: 78, done.
remote: Counting objects: 100% (78/78), done.
remote: Compressing objects: 100% (75/75), done.
remote: Total 78 (delta 1), reused 39 (delta 1), pack-reused 0
Receiving objects: 100% (78/78), 170.37 KiB | 2.43 MiB/s, done.
Resolving deltas: 100% (1/1), done.

failed to set up installer: Missing application icon at "/tmp/v3/v3/Icon.png"

The error seems to be that the installer expects an Icon.png file and doesn't read FyneApp.toml? I'm quite sure that Rymdport used to work when installing through fyne get but the last time I tested was likely over a year ago (or more likely even longer).

[andydotxyz]

The error seems to be that the installer expects an Icon.png file and doesn't read
FyneApp.toml? I'm quite sure that Rymdport used to work when installing through fyne get
but the last time I tested was likely over a year ago (or more likely even longer)

This is not a regression, the icon handling is somewhat special for get but it should be resolved separately. You can pass "-icon" command to work around it for now.

[Jacalz]

Hmm. This just seems to get stuck after cloning the repository from what I can tell. It resolves the deltas and then just seems to do absolutely nothing when trying to download fyne_demo. I'm not sure what is going on.

[Jacalz]

Actually: It might just be my Go install being stupidly slow at compiling for some reason. Will test again tomorrow.