Deal with protected solution providers first

For positive dependencies this isn't giving much as the dependency
should already be satisfied by such a provider if its protectiveness
would help, but it doesn't hurt to check them first and for negative
dependencies it means that we check those first which are the most
likely to fail to be removed – which is a good idea.

1 files changed, 6 insertions, 3 deletions

diff --git a/apt-pkg/depcache.cc b/apt-pkg/depcache.cc
index eb0a02f8f..393c9977a 100644
--- a/apt-pkg/depcache.cc
+++ b/apt-pkg/depcache.cc
@@ -983,13 +983,16 @@ bool pkgDepCache::IsModeChangeOk(ModeList const mode, PkgIterator const &Pkg,
 									/*}}}*/
 struct CompareProviders							/*{{{*/
 {
+   pkgDepCache const &Cache;
    pkgCache::PkgIterator const Pkg;
-   explicit CompareProviders(pkgCache::DepIterator const &Dep) : Pkg(Dep.TargetPkg()) {};
-   //bool operator() (APT::VersionList::iterator const &AV, APT::VersionList::iterator const &BV)
+   explicit CompareProviders(pkgDepCache const &pCache, pkgCache::DepIterator const &Dep) : Cache{pCache}, Pkg{Dep.TargetPkg()} {}
    bool operator() (pkgCache::VerIterator const &AV, pkgCache::VerIterator const &BV)
    {
       pkgCache::PkgIterator const A = AV.ParentPkg();
       pkgCache::PkgIterator const B = BV.ParentPkg();
+      // Deal with protected first as if they don't work we usually have a problem
+      if (Cache[A].Protect() != Cache[B].Protect())
+	 return Cache[A].Protect();
       // Prefer MA:same packages if other architectures for it are installed
       if ((AV->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same ||
 	  (BV->MultiArch & pkgCache::Version::Same) == pkgCache::Version::Same)
@@ -1298,7 +1301,7 @@ static bool MarkInstall_InstallDependencies(pkgDepCache &Cache, bool const Debug
 	    continue;
 
 	 APT::VersionVector verlist = APT::VersionVector::FromDependency(CacheFile, Start, APT::CacheSetHelper::CANDIDATE);
-	 std::sort(verlist.begin(), verlist.end(), CompareProviders{Start});
+	 std::sort(verlist.begin(), verlist.end(), CompareProviders{Cache, Start});
 	 for (auto const &Ver : verlist)
 	 {
 	    auto P = Ver.ParentPkg();