[ HttpFoundation ] BinaryFileResponse sends empty file.

[j4nr6n]

Q	A
Branch?	3.4
Bug fix?	yes?
New feature?	no
BC breaks?	no
Deprecations?	no
Tests pass?	yes, with the exception of preexisting, unrelated failures
Fixed tickets	#28237
License	MIT
Doc PR

When you call BinaryFileResponse#sendContent() without first calling prepare() the response is sent but the contents are empty. prepare() properly initializes the $maxlen and $offset properties. However, sendContent() doesn't do any sanity checking, and so, uses the uninitialized properties. This causes stream_copy_to_stream() to copy empty contents and the file that is sent, to contain nothing.

This change initializes the properties at definition instead of in prepare().

Additionally:

• Bug fixes must be submitted against the lowest branch where they apply

I'm not sure how early this bug exists, or how far back to go. I'll check to see if 2.7 and 2.8 are affected and report back.

[j4nr6n]

Test app, for reference

[j4nr6n]

See #28278