Allow pkgDepCache to be asked to check internal consistency

For speed reasons pkgDepCache initializes its state once and then has a
battery of update calls you have to invoke in the right order to update
the various states – all in the name of speed. In debug and/or
simulation mode we can sacrifice this speed for a bit of extra checking
though to verify that we haven't made some critical mistake like #961266.

3 files changed, 106 insertions, 5 deletions

diff --git a/apt-pkg/algorithms.cc b/apt-pkg/algorithms.cc
index f000b7f39..3fdb5116e 100644
--- a/apt-pkg/algorithms.cc
+++ b/apt-pkg/algorithms.cc
@@ -58,6 +58,8 @@ pkgSimulate::pkgSimulate(pkgDepCache *Cache) : pkgPackageManager(Cache),
    string Jnk = "SIMULATE";
    for (decltype(PackageCount) I = 0; I != PackageCount; ++I)
       FileNames[I] = Jnk;
+
+   Cache->CheckConsistency("simulate");
 }
 									/*}}}*/
 // Simulate::~Simulate - Destructor					/*{{{*/
@@ -721,6 +723,9 @@ bool pkgProblemResolver::ResolveInternal(bool const BrokenFix)
 {
    pkgDepCache::ActionGroup group(Cache);
 
+   if (Debug)
+      Cache.CheckConsistency("resolve start");
+
    // Record which packages are marked for install
    bool Again = false;
    do
@@ -1152,6 +1157,8 @@ bool pkgProblemResolver::ResolveInternal(bool const BrokenFix)
       }
    }
 
+   if (Debug)
+      Cache.CheckConsistency("resolve done");
 
    return true;
 }
@@ -1211,6 +1218,9 @@ bool pkgProblemResolver::ResolveByKeepInternal()
 {
    pkgDepCache::ActionGroup group(Cache);
 
+   if (Debug)
+      Cache.CheckConsistency("keep start");
+
    MakeScores();
 
    /* We have to order the packages so that the broken fixing pass 
@@ -1341,6 +1351,10 @@ bool pkgProblemResolver::ResolveByKeepInternal()
    }
 
    delete[] PList;
+
+   if (Debug)
+      Cache.CheckConsistency("keep done");
+
    return true;
 }
 									/*}}}*/
diff --git a/apt-pkg/depcache.cc b/apt-pkg/depcache.cc
index fa0bd8ed5..aa10d8282 100644
--- a/apt-pkg/depcache.cc
+++ b/apt-pkg/depcache.cc
@@ -118,6 +118,88 @@ pkgDepCache::~pkgDepCache()
    delete delLocalPolicy;
 }
 									/*}}}*/
+bool pkgDepCache::CheckConsistency(char const *const msgtag)		/*{{{*/
+{
+   auto const OrigPkgState = PkgState;
+   auto const OrigDepState = DepState;
+
+   PkgState = new StateCache[Head().PackageCount];
+   DepState = new unsigned char[Head().DependsCount];
+   memset(PkgState,0,sizeof(*PkgState)*Head().PackageCount);
+   memset(DepState,0,sizeof(*DepState)*Head().DependsCount);
+
+   auto const origUsrSize = iUsrSize;
+   auto const origDownloadSize = iDownloadSize;
+   auto const origInstCount = iInstCount;
+   auto const origDelCount = iDelCount;
+   auto const origKeepCount = iKeepCount;
+   auto const origBrokenCount = iBrokenCount;
+   auto const origPolicyBrokenCount = iPolicyBrokenCount;
+   auto const origBadCount = iBadCount;
+
+   for (PkgIterator I = PkgBegin(); not I.end(); ++I)
+   {
+      auto &State = PkgState[I->ID];
+      auto const &OrigState = OrigPkgState[I->ID];
+      State.iFlags = OrigState.iFlags;
+
+      State.CandidateVer = OrigState.CandidateVer;
+      State.InstallVer = OrigState.InstallVer;
+      State.Mode = OrigState.Mode;
+      State.Update(I,*this);
+      State.Status = OrigState.Status;
+   }
+   PerformDependencyPass(nullptr);
+
+   _error->PushToStack();
+#define APT_CONSISTENCY_CHECK(VAR,STR) \
+   if (orig##VAR != i##VAR) \
+      _error->Warning("Internal Inconsistency in pkgDepCache: " #VAR " " STR " vs " STR " (%s)", i##VAR, orig##VAR, msgtag)
+   APT_CONSISTENCY_CHECK(UsrSize, "%lld");
+   APT_CONSISTENCY_CHECK(DownloadSize, "%lld");
+   APT_CONSISTENCY_CHECK(InstCount, "%lu");
+   APT_CONSISTENCY_CHECK(DelCount, "%lu");
+   APT_CONSISTENCY_CHECK(KeepCount, "%lu");
+   APT_CONSISTENCY_CHECK(BrokenCount, "%lu");
+   APT_CONSISTENCY_CHECK(PolicyBrokenCount, "%lu");
+   APT_CONSISTENCY_CHECK(BadCount, "%lu");
+#undef APT_CONSISTENCY_CHECK
+
+   for (PkgIterator P = PkgBegin(); not P.end(); ++P)
+   {
+      auto const &State = PkgState[P->ID];
+      auto const &OrigState = OrigPkgState[P->ID];
+      if (State.Status != OrigState.Status)
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Status of %s is %d vs %d (%s)", P.FullName().c_str(), State.Status, OrigState.Status, msgtag);
+      if (State.NowBroken() != OrigState.NowBroken())
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Now broken for %s is %d vs %d (%s)", P.FullName().c_str(), static_cast<int>(State.DepState), static_cast<int>(OrigState.DepState), msgtag);
+      if (State.NowPolicyBroken() != OrigState.NowPolicyBroken())
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Now policy broken for %s is %d vs %d (%s)", P.FullName().c_str(), static_cast<int>(State.DepState), static_cast<int>(OrigState.DepState), msgtag);
+      if (State.InstBroken() != OrigState.InstBroken())
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Install broken for %s is %d vs %d (%s)", P.FullName().c_str(), static_cast<int>(State.DepState), static_cast<int>(OrigState.DepState), msgtag);
+      if (State.InstPolicyBroken() != OrigState.InstPolicyBroken())
+	 _error->Warning("Internal Inconsistency in pkgDepCache: Install broken for %s is %d vs %d (%s)", P.FullName().c_str(), static_cast<int>(State.DepState), static_cast<int>(OrigState.DepState), msgtag);
+   }
+
+   auto inconsistent = _error->PendingError();
+   _error->MergeWithStack();
+
+   delete[] PkgState;
+   delete[] DepState;
+   PkgState = OrigPkgState;
+   DepState = OrigDepState;
+   iUsrSize = origUsrSize;
+   iDownloadSize = origDownloadSize;
+   iInstCount = origInstCount;
+   iDelCount = origDelCount;
+   iKeepCount = origKeepCount;
+   iBrokenCount = origBrokenCount;
+   iPolicyBrokenCount = origPolicyBrokenCount;
+   iBadCount = origBadCount;
+
+   return not inconsistent;
+}
+									/*}}}*/
 // DepCache::Init - Generate the initial extra structures.		/*{{{*/
 // ---------------------------------------------------------------------
 /* This allocats the extension buffers and initializes them. */
@@ -655,8 +737,8 @@ void pkgDepCache::UpdateVerState(PkgIterator const &Pkg)
 // ---------------------------------------------------------------------
 /* This will figure out the state of all the packages and all the 
    dependencies based on the current policy. */
-void pkgDepCache::Update(OpProgress * const Prog)
-{   
+void pkgDepCache::PerformDependencyPass(OpProgress * const Prog)
+{
    iUsrSize = 0;
    iDownloadSize = 0;
    iInstCount = 0;
@@ -666,7 +748,6 @@ void pkgDepCache::Update(OpProgress * const Prog)
    iPolicyBrokenCount = 0;
    iBadCount = 0;
 
-   // Perform the depends pass
    int Done = 0;
    for (PkgIterator I = PkgBegin(); I.end() != true; ++I, ++Done)
    {
@@ -699,10 +780,12 @@ void pkgDepCache::Update(OpProgress * const Prog)
       UpdateVerState(I);
       AddStates(I);
    }
-
    if (Prog != 0)
       Prog->Progress(Done);
-
+}
+void pkgDepCache::Update(OpProgress * const Prog)
+{
+   PerformDependencyPass(Prog);
    readStateFile(Prog);
 }
 									/*}}}*/
diff --git a/apt-pkg/depcache.h b/apt-pkg/depcache.h
index ff1b37374..d9bb69a18 100644
--- a/apt-pkg/depcache.h
+++ b/apt-pkg/depcache.h
@@ -502,6 +502,8 @@ class APT_PUBLIC pkgDepCache : protected pkgCache::Namespace
    pkgDepCache(pkgCache * const Cache,Policy * const Plcy = 0);
    virtual ~pkgDepCache();
 
+   bool CheckConsistency(char const *const msgtag = "");
+
    protected:
    // methods call by IsInstallOk
    bool IsInstallOkMultiArchSameVersionSynced(PkgIterator const &Pkg,
@@ -521,6 +523,8 @@ class APT_PUBLIC pkgDepCache : protected pkgCache::Namespace
 
    APT_HIDDEN bool MarkInstall_StateChange(PkgIterator const &Pkg, bool AutoInst, bool FromUser);
    APT_HIDDEN bool MarkInstall_DiscardInstall(PkgIterator const &Pkg);
+
+   APT_HIDDEN void PerformDependencyPass(OpProgress * const Prog);
 };
 
 #endif