[kdevelop/kdevelop] kdevplatform/language/duchain: DUChain: Do not randomly discard top-contextes on shutdown

Git commit ec0dd0d8a91b29e194c9676aa9d57a21dacc5713 by Jarmo Tiitto.
Committed on 02/08/2026 at 13:13.
Pushed by jatothrim into branch 'master'.

DUChain: Do not randomly discard top-contextes on shutdown

Reviewing the DUChainPrivate::cleanupTopContexts() reveals an
astonishing fact: we are selecting a random set of top-contextes to be
discarded on DUChain::shutdown(). The discarded data will be recreated
on the session's next launch causing a large amount of wasted work to be
done.

Get rid of the cleanupTopContexts() step since it is actively harmful
on loading the session the next time.

M  +0    -8    kdevplatform/language/duchain/duchain.cpp
M  +0    -88   kdevplatform/language/duchain/duchainprivate.cpp
M  +0    -9    kdevplatform/language/duchain/duchainprivate.h

https://invent.kde.org/kdevelop/kdevelop/-/commit/ec0dd0d8a91b29e194c9676aa9d57a21dacc5713

diff --git a/kdevplatform/language/duchain/duchain.cpp b/kdevplatform/language/duchain/duchain.cpp
index 3a9f5fdcfd..3ea70bde0b 100644
--- a/kdevplatform/language/duchain/duchain.cpp
+++ b/kdevplatform/language/duchain/duchain.cpp
@@ -574,14 +574,6 @@ void DUChain::shutdown()
 
     QMutexLocker lock(&sdDUChainPrivate->cleanupMutex());
 
-    {
-        //Acquire write-lock of the repository, so when kdevelop crashes in that process, the repository is discarded
-        //Crashes here may happen in an inconsistent state, thus this makes sense, to protect the user from more crashes
-        globalItemRepositoryRegistry().lockForWriting();
-        sdDUChainPrivate->cleanupTopContexts();
-        globalItemRepositoryRegistry().unlockForWriting();
-    }
-
     sdDUChainPrivate->doMoreCleanup(); //Must be done _before_ finalCleanup, else we may be deleting yet needed data
 
     sdDUChainPrivate->m_openDocumentContexts.clear();
diff --git a/kdevplatform/language/duchain/duchainprivate.cpp b/kdevplatform/language/duchain/duchainprivate.cpp
index 82886ccf5d..2dc0de55d1 100644
--- a/kdevplatform/language/duchain/duchainprivate.cpp
+++ b/kdevplatform/language/duchain/duchainprivate.cpp
@@ -744,94 +744,6 @@ unloadContexts:
         return ret;
     }
 
-    struct CleanupListVisitor
-    {
-        QList<uint> checkContexts;
-        bool operator()(const EnvironmentInformationItem* item)
-        {
-            checkContexts << item->m_topContext;
-            return true;
-        }
-    };
-
-    ///Will check a selection of all top-contexts for up-to-date ness, and remove them if out of date
-    void DUChainPrivate::cleanupTopContexts()
-    {
-        DUChainWriteLocker lock(DUChain::lock());
-        qCDebug(LANGUAGE) << "cleaning top-contexts";
-        CleanupListVisitor visitor;
-        uint startPos = 0;
-        LockedItemRepository::write<EnvironmentInformation>([&visitor](EnvironmentInformationRepo& repo) {
-            repo.visitAllItems(visitor);
-        });
-
-        int checkContextsCount = maxFinalCleanupCheckContexts;
-        int percentageOfContexts = (visitor.checkContexts.size() * 100) / minimumFinalCleanupCheckContextsPercentage;
-
-        if (checkContextsCount < percentageOfContexts)
-            checkContextsCount = percentageOfContexts;
-
-        if (visitor.checkContexts.size() > (int)checkContextsCount)
-            startPos = QRandomGenerator::global()->bounded(visitor.checkContexts.size() - checkContextsCount);
-
-        int endPos = startPos + maxFinalCleanupCheckContexts;
-        if (endPos > visitor.checkContexts.size())
-            endPos = visitor.checkContexts.size();
-        QSet<uint> check;
-        for (int a = startPos; a < endPos && check.size() < checkContextsCount; ++a)
-            if (check.size() < checkContextsCount)
-                addContextsForRemoval(check, IndexedTopDUContext(visitor.checkContexts[a]));
-
-        for (uint topIndex : std::as_const(check)) {
-            IndexedTopDUContext top(topIndex);
-            if (top.data()) {
-                qCDebug(LANGUAGE) << "removing top-context for" << top.data()->url().str() <<
-                    "because it is out of date";
-                instance->removeDocumentChain(top.data());
-            }
-        }
-
-        qCDebug(LANGUAGE) << "check ready";
-    }
-
-    void DUChainPrivate::addContextsForRemoval(QSet<uint>& topContexts, IndexedTopDUContext top)
-    {
-        if (topContexts.contains(top.index()))
-            return;
-
-        QExplicitlySharedDataPointer<ParsingEnvironmentFile> info(instance->environmentFileForDocument(top));
-        ///@todo Also check if the context is "useful"(Not a duplicate context, imported by a useful one, ...)
-        if (info && info->needsUpdate()) {
-            //This context will be removed
-        } else {
-            return;
-        }
-
-        topContexts.insert(top.index());
-
-        if (info) {
-            //Check whether importers need to be removed as well
-            const QList<QExplicitlySharedDataPointer<ParsingEnvironmentFile>> importers = info->importers();
-
-            QSet<QExplicitlySharedDataPointer<ParsingEnvironmentFile>> checkNext;
-
-            //Do breadth first search, so less imports/importers have to be loaded, and a lower depth is reached
-
-            for (auto& importer : importers) {
-                IndexedTopDUContext c = importer->indexedTopContext();
-                // Prevent useless recursion
-                if (Algorithm::insert(topContexts, c.index()).inserted) {
-                    checkNext.insert(importer);
-                }
-            }
-
-            for (auto& parsingEnvFile : std::as_const(checkNext)) {
-                topContexts.remove(parsingEnvFile->indexedTopContext().index()); // Enable full check again
-                addContextsForRemoval(topContexts, parsingEnvFile->indexedTopContext());
-            }
-        }
-    }
-
     ///Stores the environment-information for the given url
     void DUChainPrivate::storeInformationList(const IndexedString& url)
     {
diff --git a/kdevplatform/language/duchain/duchainprivate.h b/kdevplatform/language/duchain/duchainprivate.h
index ef5a9f0e9d..13dcd1aead 100644
--- a/kdevplatform/language/duchain/duchainprivate.h
+++ b/kdevplatform/language/duchain/duchainprivate.h
@@ -67,10 +67,6 @@ const int SOFT_CLEANUP_STEPS = 1;
 
 // seconds to wait before trying to cleanup the DUChain
 const uint cleanupEverySeconds = 200;
-
-///Approximate maximum count of top-contexts that are checked during final cleanup
-const uint maxFinalCleanupCheckContexts = 2000;
-const uint minimumFinalCleanupCheckContextsPercentage = 10; //Check at least n% of all top-contexts during cleanup
 }
 
 namespace KDevelop {
@@ -462,13 +458,8 @@ public:
     ///@warning no other mutexes should be locked, as that may lead to a dedalock
     ParsingEnvironmentFile* loadInformation(uint topContextIndex);
 
-    ///Will check a selection of all top-contexts for up-to-date ness, and remove them if out of date
-    void cleanupTopContexts();
-
 private:
 
-    void addContextsForRemoval(QSet<uint>& topContexts, IndexedTopDUContext top);
-
     ///Stores the environment-information for the given url
     void storeInformationList(const IndexedString& url);