set(CACHE): do not remove normal variable

Fixes: #22038

5 files changed, 50 insertions, 10 deletions

diff --git a/Source/cmFindBase.cxx b/Source/cmFindBase.cxx
index 6296d06..c1281e3 100644
--- a/Source/cmFindBase.cxx
+++ b/Source/cmFindBase.cxx
@@ -357,11 +357,17 @@ void cmFindBase::NormalizeFindResult()
       this->Makefile->GetCMakeInstance()->AddCacheEntry(
         this->VariableName, value.c_str(), this->VariableDocumentation.c_str(),
         this->VariableType);
-      // if there was a definition then remove it
-      // This is required to ensure same behavior as
-      // cmMakefile::AddCacheDefinition.
-      // See #22038 for problems raised by this behavior.
-      this->Makefile->RemoveDefinition(this->VariableName);
+      if (this->Makefile->GetPolicyStatus(cmPolicies::CMP0126) ==
+          cmPolicies::NEW) {
+        if (this->Makefile->IsNormalDefinitionSet(this->VariableName)) {
+          this->Makefile->AddDefinition(this->VariableName, value);
+        }
+      } else {
+        // if there was a definition then remove it
+        // This is required to ensure same behavior as
+        // cmMakefile::AddCacheDefinition.
+        this->Makefile->RemoveDefinition(this->VariableName);
+      }
     }
   } else {
     // If the user specifies the entry on the command line without a
@@ -371,6 +377,14 @@ void cmFindBase::NormalizeFindResult()
       this->Makefile->AddCacheDefinition(this->VariableName, "",
                                          this->VariableDocumentation.c_str(),
                                          this->VariableType);
+      if (this->Makefile->GetPolicyStatus(cmPolicies::CMP0126) ==
+            cmPolicies::NEW &&
+          this->Makefile->IsNormalDefinitionSet(this->VariableName)) {
+        this->Makefile->AddDefinition(
+          this->VariableName,
+          *this->Makefile->GetCMakeInstance()->GetCacheDefinition(
+            this->VariableName));
+      }
     }
   }
 }
@@ -379,17 +393,28 @@ void cmFindBase::StoreFindResult(const std::string& value)
 {
   bool force =
     this->Makefile->GetPolicyStatus(cmPolicies::CMP0125) == cmPolicies::NEW;
+  bool updateNormalVariable =
+    this->Makefile->GetPolicyStatus(cmPolicies::CMP0126) == cmPolicies::NEW;
 
   if (!value.empty()) {
     this->Makefile->AddCacheDefinition(this->VariableName, value,
                                        this->VariableDocumentation.c_str(),
                                        this->VariableType, force);
+    if (updateNormalVariable &&
+        this->Makefile->IsNormalDefinitionSet(this->VariableName)) {
+      this->Makefile->AddDefinition(this->VariableName, value);
+    }
     return;
   }
 
   this->Makefile->AddCacheDefinition(
     this->VariableName, cmStrCat(this->VariableName, "-NOTFOUND"),
     this->VariableDocumentation.c_str(), this->VariableType, force);
+  if (updateNormalVariable &&
+      this->Makefile->IsNormalDefinitionSet(this->VariableName)) {
+    this->Makefile->AddDefinition(this->VariableName,
+                                  cmStrCat(this->VariableName, "-NOTFOUND"));
+  }
 
   if (this->Required) {
     this->Makefile->IssueMessage(
diff --git a/Source/cmFindPackageCommand.cxx b/Source/cmFindPackageCommand.cxx
index 3719fe1..fba736e 100644
--- a/Source/cmFindPackageCommand.cxx
+++ b/Source/cmFindPackageCommand.cxx
@@ -1138,6 +1138,11 @@ bool cmFindPackageCommand::FindConfig()
   // We force the value since we do not get here if it was already set.
   this->Makefile->AddCacheDefinition(this->Variable, init, help.c_str(),
                                      cmStateEnums::PATH, true);
+  if (this->Makefile->GetPolicyStatus(cmPolicies::CMP0126) ==
+        cmPolicies::NEW &&
+      this->Makefile->IsNormalDefinitionSet(this->Variable)) {
+    this->Makefile->AddDefinition(this->Variable, init);
+  }
 
   return found;
 }
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 4ffd47b..d7987c2 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -1962,10 +1962,10 @@ void cmMakefile::AddCacheDefinition(const std::string& name, const char* value,
     }
   }
   this->GetCMakeInstance()->AddCacheEntry(name, value, doc, type);
-  // if there was a definition then remove it
-  // The method cmFindBase::NormalizeFindResult also apply same workflow.
-  // See #22038 for problems raised by this behavior.
-  this->StateSnapshot.RemoveDefinition(name);
+  if (this->GetPolicyStatus(cmPolicies::CMP0126) != cmPolicies::NEW) {
+    // if there was a definition then remove it
+    this->StateSnapshot.RemoveDefinition(name);
+  }
 }
 
 void cmMakefile::MarkVariableAsUsed(const std::string& var)
diff --git a/Source/cmOptionCommand.cxx b/Source/cmOptionCommand.cxx
index a58e2f8..bae67e0 100644
--- a/Source/cmOptionCommand.cxx
+++ b/Source/cmOptionCommand.cxx
@@ -68,6 +68,13 @@ bool cmOptionCommand(std::vector<std::string> const& args,
   bool init = cmIsOn(initialValue);
   status.GetMakefile().AddCacheDefinition(args[0], init ? "ON" : "OFF",
                                           args[1].c_str(), cmStateEnums::BOOL);
+  if (status.GetMakefile().GetPolicyStatus(cmPolicies::CMP0077) !=
+        cmPolicies::NEW &&
+      status.GetMakefile().GetPolicyStatus(cmPolicies::CMP0126) ==
+        cmPolicies::NEW) {
+    // if there was a definition then remove it
+    status.GetMakefile().GetStateSnapshot().RemoveDefinition(args[0]);
+  }
 
   if (checkAndWarn) {
     const auto* existsAfterSet =
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index 3ebb17d..f7c0d25 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -376,7 +376,10 @@ class cmMakefile;
   SELECT(POLICY, CMP0125,                                                     \
          "find_(path|file|library|program) have consistent behavior for "     \
          "cache variables.",                                                  \
-         3, 21, 0, cmPolicies::WARN)
+         3, 21, 0, cmPolicies::WARN)                                          \
+  SELECT(POLICY, CMP0126,                                                     \
+         "set(CACHE) does not remove a normal variable of the same name.", 3, \
+         21, 0, cmPolicies::WARN)
 
 #define CM_SELECT_ID(F, A1, A2, A3, A4, A5, A6) F(A1)
 #define CM_FOR_EACH_POLICY_ID(POLICY)                                         \