Proxy port 80 not working

[lokomiro]

Describe the problem

Users may access the Internet via a proxy server. Arduino IDE can be configured for this use case via the "Network" tab of the "Preferences" dialog.

🐛 When the "Port number" preference is set to 80, the proxy configuration is not correctly handled by the IDE, with two distinct symptoms:

A. The IDE is not able to connect to the network (lower left corner of IDE reports "Offline", libraries etc. are not accessible).
B. The "Port number" preference is blank.

To reproduce

The following demonstrates the '"Port number" preference is blank' fault:

1. Select File > Preferences... from the Arduino IDE menus.
   The "Preferences" dialog will open
2. Select the "Network" tab in the dialog.
3. Select the "Manual proxy configuration" radio button.
4. Configure proxy as follows:
   • Select the "HTTP" radio button.
   • Set "Host name" to example.com
   • Set "Port number" to 80
   • Set "Username" to foo
   • Set "Password" to bar
5. Click the "OK" button.
6. Select File > Preferences... from the Arduino IDE menus.
7. Click the "Network" tab.
   🙂 The proxy configuration is as you specified at step (4).
8. Click the "OK" button.
9. Select File > Quit (or Arduino > Quit Arduino for macOS users) from the Arduino IDE menus.
   All Arduino IDE windows will close.
10. Start Arduino IDE.
11. Select File > Preferences... from the Arduino IDE menus.
12. Click the "Network" tab.

🐛 The "Port number" preference is blank.

Expected behavior

• The IDE is able to access the Internet through the proxy server when it uses port 80.
• The preferences shows the configured port number when the preference is set to 80.

Arduino IDE version

Original report

2.2.2-nightly-20240119

Last verified with

2.3.4

Operating system

Windows

Operating system version

• Windows 10 Home 10.10.19045
• Windows 11

Additional context

The fault does not occur with other port number values.

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I can see that the port number is set to 80 in the arduino-cli.yaml configuration file (even though it is not shown in the Preferences dialog):

Issue checklist

• I searched for previous reports in the issue tracker
• I verified the problem still occurs when using the latest nightly build
• My report contains all necessary details