Bug#921814: lintian: spelling_exceptions() only considers binary packages

[Johannes 'josch' Schauer <josch@debian.org>]

Package: lintian
Version: 2.6.0
Severity: normal

Hi,

the function spelling_exceptions() only considers binary packages to add
exceptions to the spell checking. This leads to situation where tags
like spelling-error-in-patch-description are emitted depending on
whether a binary package was added to the lintian call. An example is
the src:alot package where we used to have an override for
spelling-error-in-patch-description but then discovered that lintian
will complain about an unused tag when we also add the binary package:

$ lintian --pedantic --display-info --display-experimental alot_0.8-1.dsc alot_0.8-1_amd64.changes
I: alot source: out-of-date-standards-version 4.2.1 (released 2018-08-25) (current is 4.3.0)
I: alot source: testsuite-autopkgtest-missing
X: alot source: upstream-metadata-file-is-missing
I: alot source: unused-override spelling-error-in-patch-description debian/patches/0003-alot-UnicodeEncodeError-for-search-queries-with-non-.patch alot a lot
N: 0 tags overridden; 1 unused override

$ lintian --pedantic --display-info --display-experimental alot_0.8-1.dsc
I: alot source: out-of-date-standards-version 4.2.1 (released 2018-08-25) (current is 4.3.0)
I: alot source: testsuite-autopkgtest-missing
X: alot source: upstream-metadata-file-is-missing
N: 1 tag overridden (1 warning)

I think what instead should happen is, that the function also considers
the source package, specifically the Source and Binary fields.

Thanks!

cheers, josch