From 87fe4286bdb3f4faffbc603697b4a6f3343fb4ec Mon Sep 17 00:00:00 2001
From: Alex Neundorf <neundorf@kde.org>
Date: Thu, 16 Aug 2012 22:46:33 +0200
Subject: fix #13474: also rescan dependencies if the depender does not exist

If the depender (e.g. foo.o) does not exist, also rescan dependencies if
one of the dependees (e.g. foo.cxx) is older than the already existing
depend.internal file, since this means it can be out of date.

Alex
---
 Source/cmDepends.cxx | 63 ++++++++++++++++++++++++++++++++++++++--------------
 Source/cmDepends.h   |  1 +
 2 files changed, 47 insertions(+), 17 deletions(-)

diff --git a/Source/cmDepends.cxx b/Source/cmDepends.cxx
index 545fe97..5a48f7f 100644
--- a/Source/cmDepends.cxx
+++ b/Source/cmDepends.cxx
@@ -98,7 +98,7 @@ bool cmDepends::Check(const char *makeFile, const char *internalFile,
   // Check whether dependencies must be regenerated.
   bool okay = true;
   std::ifstream fin(internalFile);
-  if(!(fin && this->CheckDependencies(fin, validDeps)))
+  if(!(fin && this->CheckDependencies(fin, internalFile, validDeps)))
     {
     // Clear all dependencies so they will be regenerated.
     this->Clear(makeFile);
@@ -143,6 +143,7 @@ bool cmDepends::WriteDependencies(const char*, const char*,
 
 //----------------------------------------------------------------------------
 bool cmDepends::CheckDependencies(std::istream& internalDepends,
+                                  const char* internalDependsFileName,
                             std::map<std::string, DependencyVector>& validDeps)
 {
   // Parse dependencies from the stream.  If any dependee is missing
@@ -186,8 +187,11 @@ bool cmDepends::CheckDependencies(std::istream& internalDepends,
       }
       */
 
-    // Dependencies must be regenerated if the dependee does not exist
-    // or if the depender exists and is older than the dependee.
+    // Dependencies must be regenerated
+    // * if the dependee does not exist
+    // * if the depender exists and is older than the dependee.
+    // * if the depender does not exist, but the dependee is newer than the
+    //   depends file
     bool regenerate = false;
     const char* dependee = this->Dependee+1;
     const char* depender = this->Depender;
@@ -211,24 +215,49 @@ bool cmDepends::CheckDependencies(std::istream& internalDepends,
         cmSystemTools::Stdout(msg.str().c_str());
         }
       }
-    else if(dependerExists)
+    else
       {
-      // The dependee and depender both exist.  Compare file times.
-      int result = 0;
-      if((!this->FileComparison->FileTimeCompare(depender, dependee,
-                                             &result) || result < 0))
+      if(dependerExists)
         {
-        // The depender is older than the dependee.
-        regenerate = true;
+        // The dependee and depender both exist.  Compare file times.
+        int result = 0;
+        if((!this->FileComparison->FileTimeCompare(depender, dependee,
+                                              &result) || result < 0))
+          {
+          // The depender is older than the dependee.
+          regenerate = true;
 
-        // Print verbose output.
-        if(this->Verbose)
+          // Print verbose output.
+          if(this->Verbose)
+            {
+            cmOStringStream msg;
+            msg << "Dependee \"" << dependee
+                << "\" is newer than depender \""
+                << depender << "\"." << std::endl;
+            cmSystemTools::Stdout(msg.str().c_str());
+            }
+          }
+        }
+      else
+        {
+        // The dependee exists, but the depender doesn't. Regenerate if the
+        // internalDepends file is older than the dependee.
+        int result = 0;
+        if((!this->FileComparison->FileTimeCompare(internalDependsFileName, dependee,
+                                              &result) || result < 0))
           {
-          cmOStringStream msg;
-          msg << "Dependee \"" << dependee
-              << "\" is newer than depender \""
-              << depender << "\"." << std::endl;
-          cmSystemTools::Stdout(msg.str().c_str());
+          // The depends-file is older than the dependee.
+          regenerate = true;
+
+          // Print verbose output.
+          if(this->Verbose)
+            {
+            cmOStringStream msg;
+            msg << "Dependee \"" << dependee
+                << "\" is newer than depends file \""
+                << internalDependsFileName << "\"." << std::endl;
+            cmSystemTools::Stdout(msg.str().c_str());
+            }
           }
         }
       }
diff --git a/Source/cmDepends.h b/Source/cmDepends.h
index 100e187..f7dc881 100644
--- a/Source/cmDepends.h
+++ b/Source/cmDepends.h
@@ -83,6 +83,7 @@ protected:
   // Return false if dependencies must be regenerated and true
   // otherwise.
   virtual bool CheckDependencies(std::istream& internalDepends,
+                                 const char* internalDependsFileName,
                            std::map<std::string, DependencyVector>& validDeps);
 
   // Finalize the dependency information for the target.
-- 
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