Merge topic 'main_dependency_diagnostic'

242c3966 add_custom_command: Diagnose MAIN_DEPENDENCY limitation.

3 files changed, 34 insertions, 0 deletions

diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index ccfe2b1..6de1c61 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -985,6 +985,33 @@ cmMakefile::AddCustomCommandToOutput(const std::vector<std::string>& outputs,
         }
       else
         {
+        std::ostringstream e;
+        cmake::MessageType messageType = cmake::AUTHOR_WARNING;
+        bool issueMessage = false;
+
+        switch(this->GetPolicyStatus(cmPolicies::CMP0057))
+          {
+          case cmPolicies::WARN:
+            e << (this->GetPolicies()->
+              GetPolicyWarning(cmPolicies::CMP0057)) << "\n";
+            issueMessage = true;
+          case cmPolicies::OLD:
+            break;
+          case cmPolicies::NEW:
+          case cmPolicies::REQUIRED_IF_USED:
+          case cmPolicies::REQUIRED_ALWAYS:
+            issueMessage = true;
+            messageType = cmake::FATAL_ERROR;
+            break;
+          }
+
+        if(issueMessage)
+          {
+          e << "\"" << main_dependency << "\" can only be specified as a "
+            "custom command MAIN_DEPENDENCY once.";
+          IssueMessage(messageType, e.str());
+          }
+
         // The existing custom command is different.  We need to
         // generate a rule file for this new command.
         file = 0;
diff --git a/Source/cmPolicies.cxx b/Source/cmPolicies.cxx
index 3a48101..07e210e 100644
--- a/Source/cmPolicies.cxx
+++ b/Source/cmPolicies.cxx
@@ -374,6 +374,11 @@ cmPolicies::cmPolicies()
     CMP0056, "CMP0056",
     "Honor link flags in try_compile() source-file signature.",
     3,2,0, cmPolicies::WARN);
+
+  this->DefinePolicy(
+    CMP0057, "CMP0057",
+    "Disallow multiple MAIN_DEPENDENCY specifications for the same file.",
+    3,3,0, cmPolicies::WARN);
 }
 
 cmPolicies::~cmPolicies()
diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index c393c2f..854b132 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -113,6 +113,8 @@ public:
     /// or keywords when unquoted.
     CMP0055, ///< Strict checking for break() command.
     CMP0056, ///< Honor link flags in try_compile() source-file signature.
+    CMP0057, ///< Disallow multiple MAIN_DEPENDENCY specifications
+    /// for the same file.
 
     /** \brief Always the last entry.
      *