From 8a6b694108f41afd1e6cdba4c91481697f9b3004 Mon Sep 17 00:00:00 2001
From: Julian Andres Klode <julian.klode@canonical.com>
Date: Mon, 10 Mar 2025 22:05:52 +0100
Subject: solver3: Correctly determine 'same' or groups

We incorrectly used the DependencyData of the first or group
member, however that only checked that the first or group member
was the same and that both either had a next member or not.
---
 apt-pkg/solver3.cc | 38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

(limited to 'apt-pkg/solver3.cc')

diff --git a/apt-pkg/solver3.cc b/apt-pkg/solver3.cc
index fde1d192b..739309c59 100644
--- a/apt-pkg/solver3.cc
+++ b/apt-pkg/solver3.cc
@@ -634,6 +634,23 @@ bool APT::Solver::Propagate()
    return true;
 }
 
+static bool SameOrGroup(pkgCache::DepIterator a, pkgCache::DepIterator b)
+{
+   while (1)
+   {
+      if (a->DependencyData != b->DependencyData)
+	 return false;
+
+      // At least one has reached the end, break
+      if (not(a->CompareOp & pkgCache::Dep::Or) || not(b->CompareOp & pkgCache::Dep::Or))
+	 break;
+
+      ++a, ++b;
+   }
+   // Fully iterated over a and b
+   return not(a->CompareOp & pkgCache::Dep::Or) && not(b->CompareOp & pkgCache::Dep::Or);
+}
+
 const APT::Solver::Clause *APT::Solver::RegisterClause(Clause &&clause)
 {
    auto &clauses = (*this)[clause.reason].clauses;
@@ -701,8 +718,8 @@ void APT::Solver::Discover(Var var)
 
 	    // This dependency is shared across all versions, skip it.
 	    if (auto &pkgClauses = (*this)[Ver.ParentPkg()].clauses;
-		std::any_of(pkgClauses.begin(), pkgClauses.end(), [start](auto &c)
-			    { return c->dep && c->dep->DependencyData == start->DependencyData; }))
+		std::any_of(pkgClauses.begin(), pkgClauses.end(), [this, start](auto &c)
+			    { return c->dep && SameOrGroup(start, pkgCache::DepIterator(cache, c->dep)); }))
 	       continue;
 
 	    auto clause = TranslateOrGroup(start, end, Var(Ver));
@@ -723,18 +740,21 @@ void APT::Solver::RegisterCommonDependencies(pkgCache::PkgIterator Pkg)
 {
    for (auto dep = Pkg.VersionList().DependsList(); not dep.end();)
    {
-      pkgCache::DepIterator start;
-      pkgCache::DepIterator end;
+      pkgCache::DepIterator start, end;
       dep.GlobOr(start, end); // advances dep
 
       bool allHaveDep = true;
-      for (auto ver = Pkg.VersionList()++; not ver.end(); ver++)
+      for (auto ver = Pkg.VersionList()++; allHaveDep && not ver.end(); ver++)
       {
 	 bool haveDep = false;
-	 for (auto otherDep = ver.DependsList(); not haveDep && not otherDep.end(); otherDep++)
-	    haveDep = otherDep->DependencyData == start->DependencyData;
-	 if (!haveDep)
-	    allHaveDep = haveDep;
+	 for (auto otherDep = ver.DependsList(); not haveDep && not otherDep.end();)
+	 {
+	    pkgCache::DepIterator otherStart, otherEnd;
+	    otherDep.GlobOr(otherStart, otherEnd); // advances other dep
+	    haveDep = SameOrGroup(start, otherStart);
+	 }
+	 if (not haveDep)
+	    allHaveDep = false;
       }
       if (not allHaveDep)
 	 continue;
-- 
cgit v1.2.3-70-g09d2