[file_selector] Android: uncaught NullPointerException on the main thread when openInputStream returns null in toFileResponse #191989

Steps to reproduce

1. On Android, call openFile() / openFiles() from file_selector.
2. Select a document whose content provider cannot serve its bytes when the result comes back: ContentResolver#openInputStream(uri) returns null (for example after the provider process crashed). The provider still answers the metadata query, so a size is known and the read is attempted.

Expected results

The call completes with the plugin's existing "Failed to read file: <uri>" error, and the app keeps running.

Actual results

FileSelectorApiImpl#toFileResponse opens the stream in a try-with-resources (a null resource is legal there) and hands it to DataInputStream#readFully, which dereferences it:

java.lang.NullPointerException
  at java.io.DataInputStream.readFully(...)
  at dev.flutter.packages.file_selector_android.FileSelectorApiImpl.toFileResponse(FileSelectorApiImpl.java:355)
  at dev.flutter.packages.file_selector_android.FileSelectorApiImpl$2.onResult(...)

Only IOException is caught there, and toFileResponse runs inside the onActivityResult listener — the main thread — so the NPE is uncaught and takes the process down. FileUtils.getPathFromCopyOfFileFromUri has the same unguarded copy(inputStream, …) one step later. This is the file_selector_android sibling of the image_picker_android null-stream crash (see #191988); #159568 covered the copy-failure case in the same callback but not a null stream.

Code sample

Any openFile() / openFiles() call; the trigger is the provider's behaviour, not app code.

Logs

Mechanism confirmed from the source on main (packages/file_selector/file_selector_android/android/src/main/java/dev/flutter/packages/file_selector_android/FileSelectorApiImpl.java, toFileResponse; FileUtils.java, getPathFromCopyOfFileFromUri).

Flutter Doctor output

Not environment-specific.