Is this still a problem nowadays? Build commands will fail even if old source file is downloaded, because newer version of source file will be searched and then fail.

Probably a warning message could be printed if source files listed in sources are not present in SPEC.

Similar to: https://pagure.io/fedpkg/issue/34, which was closed. Resolve it here.

This issue has been unresolved for more than a year, and is going to be closed within a week if no further action is taken. If you feel this is in error, please contact me.
This is a cleaning process suggested by Jay Greguske. Copy of this ticket was already closed in JIRA tracker.

I think I'm in a similar situation and I'm confused.
My sources file is still showing an old version. Before upgrading it with fedpkg new-sources I must download the new source tarball. I've already upgraded the version in my .spec file and commited the changes. I would expect fedpkg sources to download the version specified in the .spec file instead of those in sources file.

I had to use spectool -g file.spec and then fedpkg new-sources file.tar.gz.

That expectation is not correct. Fedpkg never downloads upstream sources. It will simply downloads whatever was uploaded to lookaside cache and is listed in sources file.

To download from upstream, spectool should indeed be used.