sanify API to get 'the' candidate version

This was discussed a while ago on #debian-apt and now that I see myself
making this mistake lets bite the bullet and fix it in the easy way out
version: Using a new name which fits with a similar named setter and
deprecate the old method instead of 'hostily' changing API.

Closes: #803471

apt-pkg/algorithms.cc

@@ -933,7 +933,7 @@ bool pkgProblemResolver::ResolveInternal(bool const BrokenFix)
 				 Start.TargetPkg()->CurrentVer == 0 &&
 				 Cache[Start.TargetPkg()].Delete() == false &&
 				 (Flags[Start.TargetPkg()->ID] & ToRemove) != ToRemove &&
-				 Cache.GetCandidateVer(Start.TargetPkg()).end() == false)
+				 Cache.GetCandidateVersion(Start.TargetPkg()).end() == false)
 			{
 			   /* Before removing or keeping the package with the broken dependency
 			      try instead to install the first not previously installed package

apt-pkg/deb/dpkgpm.cc

@@ -1718,11 +1718,11 @@ void pkgDPkgPM::WriteApportReport(const char *pkgpath, const char *errormsg)
    if(pos != string::npos)
       pkgname = pkgname.substr(0, pos);
 
-   // find the package versin and source package name
+   // find the package version and source package name
    pkgCache::PkgIterator Pkg = Cache.FindPkg(pkgname);
    if (Pkg.end() == true)
       return;
-   pkgCache::VerIterator Ver = Cache.GetCandidateVer(Pkg);
+   pkgCache::VerIterator Ver = Cache.GetCandidateVersion(Pkg);
    if (Ver.end() == true)
       return;
    pkgver = Ver.VerStr() == NULL ? "unknown" : Ver.VerStr();

apt-pkg/depcache.cc

@@ -153,7 +153,7 @@ bool pkgDepCache::Init(OpProgress * const Prog)
       State.iFlags = 0;
 
       // Figure out the install version
-      State.CandidateVer = GetCandidateVer(I);
+      State.CandidateVer = LocalPolicy->GetCandidateVer(I);
       State.InstallVer = I.CurrentVer();
       State.Mode = ModeKeep;
 
@@ -1467,6 +1467,11 @@ void pkgDepCache::SetReInstall(PkgIterator const &Pkg,bool To)
    }
 }
 									/*}}}*/
+pkgCache::VerIterator pkgDepCache::GetCandidateVersion(PkgIterator const &Pkg)/*{{{*/
+{
+   return PkgState[Pkg->ID].CandidateVerIter(*this);
+}
+									/*}}}*/
 // DepCache::SetCandidateVersion - Change the candidate version		/*{{{*/
 // ---------------------------------------------------------------------
 /* */

apt-pkg/depcache.h

@@ -360,9 +360,10 @@ class pkgDepCache : protected pkgCache::Namespace
 
    inline pkgCache &GetCache() {return *Cache;};
    inline pkgVersioningSystem &VS() {return *Cache->VS;};
-   
+
    // Policy implementation
-   inline VerIterator GetCandidateVer(PkgIterator const &Pkg) {return LocalPolicy->GetCandidateVer(Pkg);};
+   APT_DEPRECATED inline VerIterator GetCandidateVer(PkgIterator const &Pkg) {return /* GetCandidateVersion(Pkg); but for API compat: */ LocalPolicy->GetCandidateVer(Pkg);};
+
    inline bool IsImportantDep(DepIterator Dep) const {return LocalPolicy->IsImportantDep(Dep);};
    inline Policy &GetPolicy() {return *LocalPolicy;};
    
@@ -413,6 +414,16 @@ class pkgDepCache : protected pkgCache::Namespace
    void MarkProtected(PkgIterator const &Pkg) { PkgState[Pkg->ID].iFlags |= Protected; };
 
    void SetReInstall(PkgIterator const &Pkg,bool To);
+
+   /** @return 'the' candidate version of a package
+    *
+    * The version returned is the version previously set explicitly via
+    * SetCandidate* methods like #SetCandidateVersion or if there wasn't one
+    * set the version as choosen via #Policy.
+    *
+    * @param Pkg is the package to return the candidate for
+    */
+   pkgCache::VerIterator GetCandidateVersion(pkgCache::PkgIterator const &Pkg);
    void SetCandidateVersion(VerIterator TargetVer);
    bool SetCandidateRelease(pkgCache::VerIterator TargetVer,
 				std::string const &TargetRel);

apt-pkg/edsp.cc

@@ -84,7 +84,7 @@ static void WriteScenarioVersion(pkgDepCache &Cache, FILE* output, pkgCache::Pkg
 	   fprintf(output, " %s\n", R->c_str());
    }
    fprintf(output, "APT-Pin: %d\n", Pin);
-   if (Cache.GetCandidateVer(Pkg) == Ver)
+   if (Cache.GetCandidateVersion(Pkg) == Ver)
       fprintf(output, "APT-Candidate: yes\n");
    if ((Cache[Pkg].Flags & pkgCache::Flag::Auto) == pkgCache::Flag::Auto)
       fprintf(output, "APT-Automatic: yes\n");
@@ -510,9 +510,10 @@ bool EDSP::WriteSolution(pkgDepCache &Cache, FILE* output)
       }
       else if (Cache[Pkg].NewInstall() == true || Cache[Pkg].Upgrade() == true)
       {
-	 fprintf(output, "Install: %d\n", Cache.GetCandidateVer(Pkg)->ID);
+	 pkgCache::VerIterator const CandVer = Cache.GetCandidateVersion(Pkg);
+	 fprintf(output, "Install: %d\n", CandVer->ID);
 	 if (Debug == true)
-	    fprintf(output, "Package: %s\nVersion: %s\n", Pkg.FullName().c_str(), Cache.GetCandidateVer(Pkg).VerStr());
+	    fprintf(output, "Package: %s\nVersion: %s\n", Pkg.FullName().c_str(), CandVer.VerStr());
       }
       else if (Cache[Pkg].Garbage == true)
       {

apt-pkg/edsp/edsplistparser.cc

@@ -111,6 +111,15 @@ bool edspListParser::ParseStatus(pkgCache::PkgIterator &Pkg,
 	 return false;
    }
 
+   // FIXME: Using an overriding pin is wrong.
+   if (Section.FindB("APT-Candidate", false))
+   {
+      std::string out;
+      strprintf(out, "Package: %s\nPin: version %s\nPin-Priority: 9999\n\n", Pkg.FullName().c_str(), Ver.VerStr());
+      if (d->preferences.Write(out.c_str(), out.length()) == false)
+	 return false;
+   }
+
    signed short const pinvalue = Section.FindI("APT-Pin", 500);
    if (pinvalue != 500)
    {

apt-private/private-source.cc

@@ -245,8 +245,8 @@ static pkgSrcRecords::Parser *FindSrc(const char *Name,
 	 // choose a good candidate and proceed with that.
 	 // Maybe we will find a source later on with the right VerTag
 	 // or RelTag
-	 pkgCache::VerIterator Ver = Cache->GetCandidateVer(Pkg);
-	 if (Ver.end() == false) 
+	 pkgCache::VerIterator const Ver = Cache->GetCandidateVersion(Pkg);
+	 if (Ver.end() == false)
 	 {
 	    if (strcmp(Ver.SourcePkgName(),Ver.ParentPkg().Name()) != 0)
 	       Src = Ver.SourcePkgName();

test/integration/test-external-dependency-solver-protocol

@@ -62,6 +62,25 @@ The following NEW packages will be installed:
 Inst coolstuff (3 experimental [amd64])
 Conf coolstuff (3 experimental [amd64])' aptget install --solver apt coolstuff -s -t experimental
 
+testsuccessequal "Reading package lists...
+Building dependency tree...
+Selected version '3' (experimental [amd64]) for 'coolstuff'
+Execute external solver...
+The following NEW packages will be installed:
+  coolstuff
+0 upgraded, 1 newly installed, 0 to remove and 2 not upgraded.
+Inst coolstuff (3 experimental [amd64])
+Conf coolstuff (3 experimental [amd64])" aptget install --solver apt coolstuff/experimental -sq=0
+
+testsuccessequal 'Reading package lists...
+Building dependency tree...
+Execute external solver...
+The following NEW packages will be installed:
+  coolstuff
+0 upgraded, 1 newly installed, 0 to remove and 2 not upgraded.
+Inst coolstuff (3 experimental [amd64])
+Conf coolstuff (3 experimental [amd64])' aptget install --solver apt coolstuff=3 -sq=0
+
 testsuccessequal 'Reading package lists...
 Building dependency tree...
 Execute external solver...