cmake_language: Add signature to DEFER calls to later times

Fixes: #19575

1 files changed, 179 insertions, 11 deletions

diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 896839b0f1..ac3a1934cc 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -16,6 +16,7 @@
 #include <cm/iterator>
 #include <cm/memory>
 #include <cm/optional>
+#include <cm/type_traits> // IWYU pragma: keep
 #include <cm/vector>
 #include <cmext/algorithm>
 #include <cmext/string_view>
@@ -274,7 +275,9 @@ cmListFileBacktrace cmMakefile::GetBacktrace() const
   return this->Backtrace;
 }
 
-void cmMakefile::PrintCommandTrace(const cmListFileFunction& lff) const
+void cmMakefile::PrintCommandTrace(
+  cmListFileFunction const& lff,
+  cm::optional<std::string> const& deferId) const
 {
   // Check if current file in the list of requested to trace...
   std::vector<std::string> const& trace_only_this_files =
@@ -322,6 +325,9 @@ void cmMakefile::PrintCommandTrace(const cmListFileFunction& lff) const
       builder["indentation"] = "";
       val["file"] = full_path;
       val["line"] = static_cast<Json::Value::Int64>(lff.Line);
+      if (deferId) {
+        val["defer"] = *deferId;
+      }
       val["cmd"] = lff.Name.Original;
       val["args"] = Json::Value(Json::arrayValue);
       for (std::string const& arg : args) {
@@ -335,8 +341,11 @@ void cmMakefile::PrintCommandTrace(const cmListFileFunction& lff) const
       break;
     }
     case cmake::TraceFormat::TRACE_HUMAN:
-      msg << full_path << "(" << lff.Line << "):  ";
-      msg << lff.Name.Original << "(";
+      msg << full_path << "(" << lff.Line << "):";
+      if (deferId) {
+        msg << "DEFERRED:" << *deferId << ":";
+      }
+      msg << "  " << lff.Name.Original << "(";
 
       for (std::string const& arg : args) {
         msg << arg << " ";
@@ -361,11 +370,12 @@ class cmMakefileCall
 {
 public:
   cmMakefileCall(cmMakefile* mf, cmListFileFunction const& lff,
-                 cmExecutionStatus& status)
+                 cm::optional<std::string> deferId, cmExecutionStatus& status)
     : Makefile(mf)
   {
     cmListFileContext const& lfc = cmListFileContext::FromCommandContext(
-      lff, this->Makefile->StateSnapshot.GetExecutionListFile());
+      lff, this->Makefile->StateSnapshot.GetExecutionListFile(),
+      std::move(deferId));
     this->Makefile->Backtrace = this->Makefile->Backtrace.Push(lfc);
     ++this->Makefile->RecursionDepth;
     this->Makefile->ExecutionStatusStack.push_back(&status);
@@ -402,7 +412,8 @@ void cmMakefile::OnExecuteCommand(std::function<void()> callback)
 }
 
 bool cmMakefile::ExecuteCommand(const cmListFileFunction& lff,
-                                cmExecutionStatus& status)
+                                cmExecutionStatus& status,
+                                cm::optional<std::string> deferId)
 {
   bool result = true;
 
@@ -417,7 +428,7 @@ bool cmMakefile::ExecuteCommand(const cmListFileFunction& lff,
   }
 
   // Place this call on the call stack.
-  cmMakefileCall stack_manager(this, lff, status);
+  cmMakefileCall stack_manager(this, lff, std::move(deferId), status);
   static_cast<void>(stack_manager);
 
   // Check for maximum recursion depth.
@@ -445,7 +456,7 @@ bool cmMakefile::ExecuteCommand(const cmListFileFunction& lff,
     if (!cmSystemTools::GetFatalErrorOccured()) {
       // if trace is enabled, print out invoke information
       if (this->GetCMakeInstance()->GetTrace()) {
-        this->PrintCommandTrace(lff);
+        this->PrintCommandTrace(lff, this->Backtrace.Top().DeferId);
       }
       // Try invoking the command.
       bool invokeSucceeded = command(lff.Arguments, status);
@@ -663,6 +674,53 @@ private:
   bool ReportError;
 };
 
+class cmMakefile::DeferScope
+{
+public:
+  DeferScope(cmMakefile* mf, std::string const& deferredInFile)
+    : Makefile(mf)
+  {
+    cmListFileContext lfc;
+    lfc.Line = cmListFileContext::DeferPlaceholderLine;
+    lfc.FilePath = deferredInFile;
+    this->Makefile->Backtrace = this->Makefile->Backtrace.Push(lfc);
+    this->Makefile->DeferRunning = true;
+  }
+
+  ~DeferScope()
+  {
+    this->Makefile->DeferRunning = false;
+    this->Makefile->Backtrace = this->Makefile->Backtrace.Pop();
+  }
+
+  DeferScope(const DeferScope&) = delete;
+  DeferScope& operator=(const DeferScope&) = delete;
+
+private:
+  cmMakefile* Makefile;
+};
+
+class cmMakefile::DeferCallScope
+{
+public:
+  DeferCallScope(cmMakefile* mf, std::string const& deferredFromFile)
+    : Makefile(mf)
+  {
+    this->Makefile->StateSnapshot =
+      this->Makefile->GetState()->CreateDeferCallSnapshot(
+        this->Makefile->StateSnapshot, deferredFromFile);
+    assert(this->Makefile->StateSnapshot.IsValid());
+  }
+
+  ~DeferCallScope() { this->Makefile->PopSnapshot(); }
+
+  DeferCallScope(const DeferCallScope&) = delete;
+  DeferCallScope& operator=(const DeferCallScope&) = delete;
+
+private:
+  cmMakefile* Makefile;
+};
+
 bool cmMakefile::ReadListFile(const std::string& filename)
 {
   std::string filenametoread = cmSystemTools::CollapseFullPath(
@@ -705,7 +763,8 @@ bool cmMakefile::ReadListFileAsString(const std::string& content,
 }
 
 void cmMakefile::RunListFile(cmListFile const& listFile,
-                             std::string const& filenametoread)
+                             std::string const& filenametoread,
+                             DeferCommands* defer)
 {
   // add this list file to the list of dependencies
   this->ListFiles.push_back(filenametoread);
@@ -736,6 +795,33 @@ void cmMakefile::RunListFile(cmListFile const& listFile,
     }
   }
 
+  // Run any deferred commands.
+  if (defer) {
+    // Add a backtrace level indicating calls are deferred.
+    DeferScope scope(this, filenametoread);
+
+    // Iterate by index in case one deferred call schedules another.
+    // NOLINTNEXTLINE(modernize-loop-convert)
+    for (size_t i = 0; i < defer->Commands.size(); ++i) {
+      DeferCommand& d = defer->Commands[i];
+      if (d.Id.empty()) {
+        // Cancelled.
+        continue;
+      }
+      // Mark as executed.
+      std::string id = std::move(d.Id);
+
+      // The deferred call may have come from another file.
+      DeferCallScope callScope(this, d.FilePath);
+
+      cmExecutionStatus status(*this);
+      this->ExecuteCommand(d.Command, status, std::move(id));
+      if (cmSystemTools::GetFatalErrorOccured()) {
+        break;
+      }
+    }
+  }
+
   this->AddDefinition("CMAKE_PARENT_LIST_FILE", currentParentFile);
   this->AddDefinition("CMAKE_CURRENT_LIST_FILE", currentFile);
   this->AddDefinition("CMAKE_CURRENT_LIST_DIR",
@@ -1678,7 +1764,9 @@ void cmMakefile::Configure()
     }
   }
 
-  this->RunListFile(listFile, currentStart);
+  this->Defer = cm::make_unique<DeferCommands>();
+  this->RunListFile(listFile, currentStart, this->Defer.get());
+  this->Defer.reset();
   if (cmSystemTools::GetFatalErrorOccured()) {
     scope.Quiet();
   }
@@ -1753,6 +1841,13 @@ void cmMakefile::AddSubDirectory(const std::string& srcPath,
                                  const std::string& binPath,
                                  bool excludeFromAll, bool immediate)
 {
+  if (this->DeferRunning) {
+    this->IssueMessage(
+      MessageType::FATAL_ERROR,
+      "Subdirectories may not be created during deferred execution.");
+    return;
+  }
+
   // Make sure the binary directory is unique.
   if (!this->EnforceUniqueDir(srcPath, binPath)) {
     return;
@@ -2960,6 +3055,68 @@ void cmMakefile::SetRecursionDepth(int recursionDepth)
   this->RecursionDepth = recursionDepth;
 }
 
+std::string cmMakefile::NewDeferId()
+{
+  return this->GetGlobalGenerator()->NewDeferId();
+}
+
+bool cmMakefile::DeferCall(std::string id, std::string file,
+                           cmListFileFunction lff)
+{
+  if (!this->Defer) {
+    return false;
+  }
+  this->Defer->Commands.emplace_back(
+    DeferCommand{ std::move(id), std::move(file), std::move(lff) });
+  return true;
+}
+
+bool cmMakefile::DeferCancelCall(std::string const& id)
+{
+  if (!this->Defer) {
+    return false;
+  }
+  for (DeferCommand& dc : this->Defer->Commands) {
+    if (dc.Id == id) {
+      dc.Id.clear();
+    }
+  }
+  return true;
+}
+
+cm::optional<std::string> cmMakefile::DeferGetCallIds() const
+{
+  cm::optional<std::string> ids;
+  if (this->Defer) {
+    ids = cmJoin(
+      cmMakeRange(this->Defer->Commands)
+        .filter([](DeferCommand const& dc) -> bool { return !dc.Id.empty(); })
+        .transform(
+          [](DeferCommand const& dc) -> std::string const& { return dc.Id; }),
+      ";");
+  }
+  return ids;
+}
+
+cm::optional<std::string> cmMakefile::DeferGetCall(std::string const& id) const
+{
+  cm::optional<std::string> call;
+  if (this->Defer) {
+    std::string tmp;
+    for (DeferCommand const& dc : this->Defer->Commands) {
+      if (dc.Id == id) {
+        tmp = dc.Command.Name.Original;
+        for (cmListFileArgument const& arg : dc.Command.Arguments) {
+          tmp = cmStrCat(tmp, ';', arg.Value);
+        }
+        break;
+      }
+    }
+    call = std::move(tmp);
+  }
+  return call;
+}
+
 MessageType cmMakefile::ExpandVariablesInStringNew(
   std::string& errorstr, std::string& source, bool escapeQuotes,
   bool noEscapes, bool atOnly, const char* filename, long line,
@@ -2997,7 +3154,12 @@ MessageType cmMakefile::ExpandVariablesInStringNew(
           switch (var.domain) {
             case NORMAL:
               if (filename && lookup == lineVar) {
-                varresult = std::to_string(line);
+                cmListFileContext const& top = this->Backtrace.Top();
+                if (top.DeferId) {
+                  varresult = cmStrCat("DEFERRED:"_s, *top.DeferId);
+                } else {
+                  varresult = std::to_string(line);
+                }
               } else {
                 value = this->GetDefinition(lookup);
               }
@@ -3561,6 +3723,12 @@ void cmMakefile::AddTargetObject(std::string const& tgtName,
 void cmMakefile::EnableLanguage(std::vector<std::string> const& lang,
                                 bool optional)
 {
+  if (this->DeferRunning) {
+    this->IssueMessage(
+      MessageType::FATAL_ERROR,
+      "Languages may not be enabled during deferred execution.");
+    return;
+  }
   if (const char* def = this->GetGlobalGenerator()->GetCMakeCFGIntDir()) {
     this->AddDefinition("CMAKE_CFG_INTDIR", def);
   }