Better handling of existing files

[Gabbar-v7]

final resultPath = await FilePicker.platform.saveFile(
        fileName: "Ascent.bak",
        bytes: Uint8List.fromList(dbFileBytes),
        type: FileType.custom,
        allowedExtensions: ['bak'],
      );

The above line for android saves the file as Ascent.bak (1) if the file aready exists in the directory. It should use the name Ascent (1).bak if file already exists.

[NavaneethMv]

I may be wrong, The file renaming behavior when a conflicting name is found is determined by the Android System when using ACTION_CREATE_DOCUMENT, not by the flutter_file_picker plugin itself.

For known file types - Android strips the extension and if conflicting name is found bumps the number and rejoin and save it properly, while on the unknown types it fails to do so since it doesn't know if that's a file type (the .bak is only considered as the part of its file name)

This is a platform limitation of Android's ACTION_CREATE_DOCUMENT intent for generic or unknown file types. The plugin must include the extension in the title to ensure the file is saved correctly, which unfortunately leads to the filename.ext (1) naming convention when duplicates occur.

[REM-moe]

@Gabbar-v7 @NavaneethMv — We might think a simple check for an existing .ext would solve this, but the problem lies deeper. The file picker uses Tika for MIME type detection; when Tika fails to identify a specific type, it defaults to */* Because the Android system receives a generic / MIME type, it treats the entire string (including the extension) as the filename. Consequently, it simply appends the increment to the end, resulting in filename.ext (1) instead of filename (1).ext."

[Gabbar-v7]

Hey @REM-moe I tried to check what you've mentioned and right correct, I dug into Tika and in tika-mimetypes.xml there are definitions for a lot of file types. The one that I'm mainly interested is .sqlite from line 5161 to 5268. It mainly requires the sqlite header as below.

00000000: 5351 4c69 7465 2066 6f72 6d61 7420 3300  SQLite format 3.

I'm using sqlite and drift which have these header in the exported file im tring to save. But still its not able to detect the extension and has the same issue as mentioned above.

final resultPath = await FilePicker.platform.saveFile(
        fileName:
            "Mindful.sqlite",
        bytes: Uint8List.fromList(dbFileBytes),
      );

I understand I can use timestamp to ignore this but fixing this feels better to me. I still need to dig deeper to debug the exact issue.