no source format specified in debian/source/format
The file debian/source/format should always exist and indicate
the desired source format. For backwards compatibility, format
'1.0' is assumed when the file doesn't exist but you should not
rely on this: at some point in the future dpkg-source will be
modified to fail when that file doesn't exist.
The rationale is that format '1.0' is no longer the recommended
format, you should usually pick one of the newer formats ('3.0
(quilt)', '3.0 (native)') but dpkg-source will not do this
automatically for you. If you want to continue using the old
format, you should be explicit about it and put '1.0' in
debian/source/format.
the diff modifies the following upstream files
When using source format '1.0' it is usually a bad idea to modify
upstream files directly as the changes end up hidden and mostly
undocumented in the .diff.gz file. Instead you should store your
changes as patches in the debian directory and apply them at
build-time. To avoid this complexity you can also use the format
'3.0 (quilt)' that offers this natively.
cannot represent change to file
Changes to upstream sources are usually stored with patch files,
but not all changes can be represented with patches: they can
only alter the content of plain text files. If you try replacing
a file with something of a different type (for example replacing
a plain file with a symlink or a directory), you will get this
error message.
newly created empty file file will not be represented in diff
Empty files can't be created with patch files. Thus this change
is not recorded in the source package and you are warned about
it.
executable mode perms of file will not be represented in diff
Patch files do not record permissions of files and thus
executable permissions are not stored in the source package. This
warning reminds you of that fact.
special mode perms of file will not be represented in diff
Patch files do not record permissions of files and thus modified
permissions are not stored in the source package. This warning
reminds you of that fact.
