Trace: process else and elseif commands correctly

There have been two bugs reported about the `else` and `elseif`
commands in the context of the tracing functionality and the json-v1
format (#23191 #22315). In essence, the reported traces referred to
the layer of the stacktrace immediately on top of the expected ones.

This MR fixes both issues. My solution adds a new parameter to the
`PrintCommandTrace` function, `commandMissingFromStack`, that callers
can specify if the command they want to report a trace for is not a
regular part of the stack maintained in `cmMakefile`. This is only the
case for `else` and `elseif`. The other bug is fixed by having the
caller pass a `cmListFileBacktrace`, which helps in getting the right
lines, file names... for the reported command.

Fixes: #23191 #22315

3 files changed, 24 insertions, 14 deletions

diff --git a/Source/cmIfCommand.cxx b/Source/cmIfCommand.cxx
index 55f6453..9cd1943 100644
--- a/Source/cmIfCommand.cxx
+++ b/Source/cmIfCommand.cxx
@@ -73,11 +73,11 @@ bool cmIfFunctionBlocker::Replay(std::vector<cmListFileFunction> functions,
     }
     // watch for our state change
     if (scopeDepth == 0 && func.LowerCaseName() == "else") {
+      cmListFileBacktrace elseBT = mf.GetBacktrace().Push(
+        cmListFileContext{ func.OriginalName(),
+                           this->GetStartingContext().FilePath, func.Line() });
 
       if (this->ElseSeen) {
-        cmListFileBacktrace elseBT = mf.GetBacktrace().Push(cmListFileContext{
-          func.OriginalName(), this->GetStartingContext().FilePath,
-          func.Line() });
         mf.GetCMakeInstance()->IssueMessage(
           MessageType::FATAL_ERROR,
           "A duplicate ELSE command was found inside an IF block.", elseBT);
@@ -92,7 +92,8 @@ bool cmIfFunctionBlocker::Replay(std::vector<cmListFileFunction> functions,
       // if trace is enabled, print a (trivially) evaluated "else"
       // statement
       if (!this->IsBlocking && mf.GetCMakeInstance()->GetTrace()) {
-        mf.PrintCommandTrace(func);
+        mf.PrintCommandTrace(func, elseBT,
+                             cmMakefile::CommandMissingFromStack::Yes);
       }
     } else if (scopeDepth == 0 && func.LowerCaseName() == "elseif") {
       cmListFileBacktrace elseifBT = mf.GetBacktrace().Push(
@@ -111,7 +112,8 @@ bool cmIfFunctionBlocker::Replay(std::vector<cmListFileFunction> functions,
       } else {
         // if trace is enabled, print the evaluated "elseif" statement
         if (mf.GetCMakeInstance()->GetTrace()) {
-          mf.PrintCommandTrace(func);
+          mf.PrintCommandTrace(func, elseifBT,
+                               cmMakefile::CommandMissingFromStack::Yes);
         }
 
         std::string errorString;
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index f0a96a8..a781d59 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -241,14 +241,14 @@ cmListFileBacktrace cmMakefile::GetBacktrace() const
   return this->Backtrace;
 }
 
-void cmMakefile::PrintCommandTrace(
-  cmListFileFunction const& lff,
-  cm::optional<std::string> const& deferId) const
+void cmMakefile::PrintCommandTrace(cmListFileFunction const& lff,
+                                   cmListFileBacktrace const& bt,
+                                   CommandMissingFromStack missing) const
 {
   // Check if current file in the list of requested to trace...
   std::vector<std::string> const& trace_only_this_files =
     this->GetCMakeInstance()->GetTraceSources();
-  std::string const& full_path = this->GetBacktrace().Top().FilePath;
+  std::string const& full_path = bt.Top().FilePath;
   std::string const& only_filename = cmSystemTools::GetFilenameName(full_path);
   bool trace = trace_only_this_files.empty();
   if (!trace) {
@@ -282,6 +282,7 @@ void cmMakefile::PrintCommandTrace(
       args.push_back(arg.Value);
     }
   }
+  cm::optional<std::string> const& deferId = bt.Top().DeferId;
 
   switch (this->GetCMakeInstance()->GetTraceFormat()) {
     case cmake::TraceFormat::TRACE_JSON_V1: {
@@ -303,9 +304,9 @@ void cmMakefile::PrintCommandTrace(
         val["args"].append(arg);
       }
       val["time"] = cmSystemTools::GetTime();
-      val["frame"] =
+      val["frame"] = (missing == CommandMissingFromStack::Yes ? 1 : 0) +
         static_cast<Json::Value::UInt64>(this->ExecutionStatusStack.size());
-      val["global_frame"] =
+      val["global_frame"] = (missing == CommandMissingFromStack::Yes ? 1 : 0) +
         static_cast<Json::Value::UInt64>(this->RecursionDepth);
       msg << Json::writeString(builder, val);
 #endif
@@ -427,7 +428,7 @@ 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->Backtrace.Top().DeferId);
+        this->PrintCommandTrace(lff, this->Backtrace);
       }
       // Try invoking the command.
       bool invokeSucceeded = command(lff.Arguments(), status);
diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index 6d44e79..c8e1e83 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -674,11 +674,18 @@ public:
                     bool copyonly, bool atOnly, bool escapeQuotes,
                     mode_t permissions = 0, cmNewLineStyle = cmNewLineStyle());
 
+  enum class CommandMissingFromStack
+  {
+    No,
+    Yes,
+  };
+
   /**
    * Print a command's invocation
    */
-  void PrintCommandTrace(cmListFileFunction const& lff,
-                         cm::optional<std::string> const& deferId = {}) const;
+  void PrintCommandTrace(
+    cmListFileFunction const& lff, cmListFileBacktrace const& bt,
+    CommandMissingFromStack missing = CommandMissingFromStack::No) const;
 
   /**
    * Set a callback that is invoked whenever ExecuteCommand is called.