YQL-21401: Introduce AutoUseYqlLibs

#### Introduce AutoUseYqlLibs flag to automatically treat yql_libs files as libraries ✎

- Added a new flag `AutoUseYqlLibs` that automatically marks files with the `yql_libs/` prefix as libraries without requiring explicit configuration
- The feature is controlled via a new command-line option and can be enabled in various execution contexts
- Removed manual library marking logic from task processing, centralizing the behavior in the facade layer
- Updated internal logic to apply the library usage flag based on the new auto-detection mechanism

<a href="https://nda.ya.ru/t/qa0kX64r7DqvtN"><font size="2">Autodescription by Yandex Code Assistant</font></a>
commit_hash:4168a7b05ff2755093b9de0e43a3995ef2fe0290

4 files changed, 21 insertions, 1 deletions

diff --git a/yql/essentials/core/facade/yql_facade.cpp b/yql/essentials/core/facade/yql_facade.cpp
index 93f64023586..60595a52c1a 100644
--- a/yql/essentials/core/facade/yql_facade.cpp
+++ b/yql/essentials/core/facade/yql_facade.cpp
@@ -214,6 +214,10 @@ void TProgramFactory::EnableRangeComputeFor() {
     EnableRangeComputeFor_ = true;
 }
 
+void TProgramFactory::EnableAutoUseYqlLibs() {
+    AutoUseYqlLibs_ = true;
+}
+
 void TProgramFactory::SetIssueReportTarget(const TString& reportTarget) {
     IssueReportTarget_ = reportTarget;
 }
@@ -317,7 +321,7 @@ TProgramPtr TProgramFactory::Create(
     return new TProgram(IssueReportTarget_, FunctionRegistry_, randomProvider, timeProvider, NextUniqueId_, DataProvidersInit_,
                         LangVer_, MaxLangVer_, VolatileResults_, UserDataTable_, Credentials_, moduleResolver, urlListerManager,
                         udfResolver, udfIndex, udfIndexPackageSet, FileStorage_, UrlPreprocessing_,
-                        GatewaysConfig_, filename, sourceCode, sessionId, Runner_, EnableRangeComputeFor_, ArrowResolver_, hiddenMode,
+                        GatewaysConfig_, filename, sourceCode, sessionId, Runner_, EnableRangeComputeFor_, AutoUseYqlLibs_, ArrowResolver_, hiddenMode,
                         qContext, RemoteLayersProviders_);
 }
 
@@ -349,6 +353,7 @@ TProgram::TProgram(
     TString sessionId,
     const TString& runner,
     bool enableRangeComputeFor,
+    bool autoUseYqlLibs,
     IArrowResolver::TPtr arrowResolver,
     EHiddenMode hiddenMode,
     const TQContext& qContext,
@@ -441,6 +446,12 @@ TProgram::TProgram(
         }
     }
 
+    for (auto& [key, block] : SavedUserDataTable_) {
+        if (autoUseYqlLibs && key.Alias().StartsWith(NYql::GetDefaultFilePrefix() + "yql_libs/")) {
+            block.Usage.Set(EUserDataBlockUsage::Library, /*val=*/true); // See YQL-21401
+        }
+    }
+
     UserDataStorage_ = MakeIntrusive<TUserDataStorage>(fileStorage, SavedUserDataTable_, udfResolver, udfIndex);
     if (auto modules = dynamic_cast<TModuleResolver*>(Modules_.get())) {
         modules->AttachUserData(UserDataStorage_);
diff --git a/yql/essentials/core/facade/yql_facade.h b/yql/essentials/core/facade/yql_facade.h
index f4c0a4e1049..80635a8e9d4 100644
--- a/yql/essentials/core/facade/yql_facade.h
+++ b/yql/essentials/core/facade/yql_facade.h
@@ -64,6 +64,7 @@ public:
     void SetFileStorage(TFileStoragePtr fileStorage);
     void SetUrlPreprocessing(IUrlPreprocessing::TPtr urlPreprocessing);
     void EnableRangeComputeFor();
+    void EnableAutoUseYqlLibs();
     void SetArrowResolver(IArrowResolver::TPtr arrowResolver);
     void SetUdfResolverLogfile(const TString& path);
     void AddRemoteLayersProvider(const TString& alias, NLayers::IRemoteLayerProviderPtr provider);
@@ -104,6 +105,7 @@ private:
     IUrlPreprocessing::TPtr UrlPreprocessing_;
     TString Runner_;
     bool EnableRangeComputeFor_ = false;
+    bool AutoUseYqlLibs_ = false;
     IArrowResolver::TPtr ArrowResolver_;
     TMaybe<TString> UdfResolverLogfile_;
     THashMap<TString, NLayers::IRemoteLayerProviderPtr> RemoteLayersProviders_;
@@ -403,6 +405,7 @@ private:
         TString sessionId,
         const TString& runner,
         bool enableRangeComputeFor,
+        bool autoUseYqlLibs,
         IArrowResolver::TPtr arrowResolver,
         EHiddenMode hiddenMode,
         const TQContext& qContext,
diff --git a/yql/essentials/tools/yql_facade_run/yql_facade_run.cpp b/yql/essentials/tools/yql_facade_run/yql_facade_run.cpp
index 98b43d63c7c..6f55213a283 100644
--- a/yql/essentials/tools/yql_facade_run/yql_facade_run.cpp
+++ b/yql/essentials/tools/yql_facade_run/yql_facade_run.cpp
@@ -364,6 +364,7 @@ void TFacadeRunOptions::Parse(int argc, const char** argv) {
     opts.AddLongOption("sql-flags", "SQL translator pragma flags").SplitHandler(&sqlFlags, ',');
     opts.AddLongOption("syntax-version", "SQL syntax version").StoreResult(&SyntaxVersion).DefaultValue(1);
     opts.AddLongOption("ansi-lexer", "Use ansi lexer").NoArgument().SetFlag(&AnsiLexer);
+    opts.AddLongOption("auto-use-yql-libs", "Implicitly mark yql_libs/* files as libraries").NoArgument().SetFlag(&AutoUseYqlLibs);
     opts.AddLongOption("assume-ydb-on-slash", "Assume YDB provider if cluster name starts with '/'").NoArgument().SetFlag(&AssumeYdbOnClusterWithSlash);
 
     opts.AddLongOption("with-final-issues", "Include some final messages (like statistic) in issues").NoArgument().SetFlag(&WithFinalIssues);
@@ -787,6 +788,10 @@ int TFacadeRunner::DoMain(int argc, const char** argv) {
     factory.SetCredentials(RunOptions_.Credentials);
     factory.EnableRangeComputeFor();
 
+    if (RunOptions_.AutoUseYqlLibs) {
+        factory.EnableAutoUseYqlLibs();
+    }
+
     if (!urlListers.empty()) {
         factory.SetUrlListerManager(MakeUrlListerManager(urlListers));
     }
diff --git a/yql/essentials/tools/yql_facade_run/yql_facade_run.h b/yql/essentials/tools/yql_facade_run/yql_facade_run.h
index aea93600061..a960ffb3764 100644
--- a/yql/essentials/tools/yql_facade_run/yql_facade_run.h
+++ b/yql/essentials/tools/yql_facade_run/yql_facade_run.h
@@ -91,6 +91,7 @@ public:
     bool AnsiLexer = false;
     bool TestAntlr4 = false;
     bool AssumeYdbOnClusterWithSlash = false;
+    bool AutoUseYqlLibs = false;
     bool TestSqlFormat = false;
     bool TestLexers = false;
     bool TestComplete = false;