[TRACKER] Error macros with cryptic messages due to not having proper custom messages defined

[Calinou]

If you stumble upon difficult-to-understand error messages (regardless of your skill level with Godot), please report them here. In your comment, make sure to state:

• Your operating system and Godot version.
• What you were doing when you got the error message. Always include code samples!
• Ideally, a minimal reproduction project that returns the error message.

Note that this issue isn't about reporting bugs, but reporting cryptic error messages. This issue is about improving error messages so users can figure things out by themselves more easily. If you stumble upon a bug, please open a dedicated issue instead of commenting in this tracker issue.

See #24199 for background.

Issues

• Using GDNative, NativeScript::_update_placeholder: generates unhelpful error message about !script_data #42948
• File.eof_reached() causes infinite while-loop on Android when read/write permissions aren't set #42959 (Added a more descriptive error message for file operations in core_bind.cpp #43076)
• Non explicit error message when setting active a Viewport that is already active #50382
• [TRACKER] Error macros with cryptic messages due to not having proper custom messages defined #42719 (comment)
• Error message for reaching maximum number of concurrent DNS queries is not explicit. #60602
• Improve error message when WebP fails to load in exported project due to the module being disabled #62712
• Unhelpful error message when ArrayMesh has a shadow_mesh with a different number of surfaces #94705
• More helpful error message for Condition "!v.is_finite()" is true #97708

For contributors

Even if you're a beginner in C++, you should be able to add error macros.

To add error explanations to existing errors, search for their origin in the source code (by reading the automatically-generated error message), suffix the error macro with _MSG and add a parameter with a custom message at the end.

We recommend adding context (such as provided arguments versus expected ones) whenever possible. Some examples:

# Best, do this whenever possible:
"Can't listen server on port 420000. The port number must be between 1 and 65535."

# OK:
"Can't listen server on port 420000."

# Bad, this doesn't give much context:
"Can't listen server."

Here are some real-world examples of improving error explanations: https://github.com/godotengine/godot/pull/41352/files, https://github.com/godotengine/godot/pull/35862/files

See Error macros in the documentation for more information.

[theoway]

Add #41493 . I've also made a PR for the same

[Anutrix]

File.eof_reached()` causes infinite while-loop on Android when read/write permissions aren't set #42959

Any idea where the error macro call should be? Is it at

godot/core/bind/core_bind.cpp

Line 1374 in 6c173e2

ERR_FAIL_COND_V_MSG(!f, String(), "File must be opened before use.");

replaced by ERR_FAIL_COND_V_MSG(!f, String(), "File must be opened before use. In case you are on the Android, check if the app has file read-write permission.");.
Or should the error be somewhere in Android platform-specific part of codebase?

[Calinou]

@Anutrix Maybe we should change the error message with an #ifdef depending on the target platform?

[Anutrix]

What's the difference between __ANDROID__ or ANDROID_ENABLED? I'm assuming one of these must be used.

[Calinou]

@Anutrix We probably want to use ANDROID_ENABLED as we use <platform>_ENABLED for other platform defines.

[kyleguarco]

I would just like to point out that the links at the bottom of the error macros page in the master branch docs are dead as of #43385