`custom_servers` has garbage value on empty config

[Omrifo4]

Which ISO version are you using?

"2024-12-01"

The installation log

I don't have one, noticed it by reading the code.

describe the problem

What's Wrong?

While parsing the pacman configuration in the installer (lib/installer.py) custom servers config is handled as follows:

# lib/installer.py, lines 540:545

custom_servers = mirror_config.custom_servers_config()
if custom_servers:
    debug(f"Custom servers:\n{custom_servers}")

    content = mirrorlist_config.read_text()
    mirrorlist_config.write_text(f"{custom_servers}\n\n{content}")

Note what happens inside mirror_config.custom_servers_config(), at lib/models/mirrors.py:

# lib/models/mirrors.py, lines 260-266
def custom_servers_config(self) -> str:
    config = "## Custom Servers\n"

    for server in self.custom_servers:
        config += f"Server = {server.url}\n"

    return config.strip()

The Possible Crash

Let's look again on the first code block above:

# lib/installer.py, lines 540:545

# empty config, so `custom_servers = "## Custom Servers\n"`
custom_servers = mirror_config.custom_servers_config()
if custom_servers:
    debug(f"Custom servers:\n{custom_servers}")

    # This will crash if there is no `mirrorlist_config` file!
    content = mirrorlist_config.read_text()
    mirrorlist_config.write_text(f"{custom_servers}\n\n{content}")

custom_servers will hold the (garbage) value ## Custom Servers\n, so we will enter the if clause.

If, for some reason, there is no mirrorlist_config file, the mirrorlist_config.read_text() will crash due to No such file or directory.

The solution is not generating this garbage value on an empty custom_servers config. I will post a fix right away.

[Torxed]

While we're at it, perhaps we shouldn't do return inside the loop.
This will not allow multiple custom mirrors.

Good catch!

[Omrifo4]

While we're at it, perhaps we shouldn't do return inside the loop. This will not allow multiple custom mirrors.

Good catch!

Oh, my bad! I copied the block incorrectly (and now fixed it).

You can see in the actual code the return statement is out of the for loop.

Thanks for noticing!

[Omrifo4]

I suggested a fix in #3498.

[Torxed]

Awesome, I'm on my phone so couldn't double check efficiently hehe.