No error or dialog if filename has an incorrect character

[tobiasht]

I was trying to run the following code on Windows.

final String? outputFile = await FilePicker.platform.saveFile(
    dialogTitle: 'Save as:',
    fileName: "Exported: $deviceName.json"
    allowedExtensions: ["json"],
    type: FileType.custom,
  );

The dialog did not open and it only returned null. I figured out that it was because i was using ":" in the filename. This might be an invalid character and might be by design. Either way, I believe it should throw an error, to easily figure out the problem.

[philenius]

@tobiasht I'm sorry, but the use of a colon : in a file name is generally not allowed on Windows, as Microsoft officially states here:
https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file#naming-conventions

[...] except for the following:

• The following reserved characters:

  • < (less than)
  • > (greater than)
  • : (colon)
  • " (double quote)
  • / (forward slash)
  • \ (backslash)
  • | (vertical bar or pipe)
  • ? (question mark)
  • * (asterisk)

• Integer value zero, sometimes referred to as the ASCII NUL character.

• Characters whose integer representations are in the range from 1 through 31, except for alternate data streams where these characters are allowed. For more information about file streams, see File Streams.

• Any other character that the target file system does not allow.

Windows Explorer doesn't even allow you to type a colon in a file name:

[tobiasht]

Yeah i understand that, but it would be more helpful to raise an invalid character exception. If that is possible. It will save people a lot of troubleshooting in the future.

[github-actions]

This issue is stale because it has been open for 14 days with no activity.

[github-actions]

This issue is stale because it has been open for 14 days with no activity.

[miguelpruivo]

@philenius do you plan to do anything regarding this?

[philenius]

@miguelpruivo please excuse my late reply. Merge request #940 adds the requested exception.