CPack: look for makensis in the PATH (#8210)

Previously, we would search in the Windows registry for the path
to makensis, and fail immediately if we could not read the registry
value, assuming that it was simply not installed.

This change looks for makensis in the PATH even if the registry value
is not there, enabling the scenario where makensis is installed without
admin privileges and never even touches HKEY_LOCAL_MACHINE during the
non-admin install.

1 files changed, 23 insertions, 9 deletions

diff --git a/Source/CPack/cmCPackNSISGenerator.cxx b/Source/CPack/cmCPackNSISGenerator.cxx
index d0eda81..f25866c 100644
--- a/Source/CPack/cmCPackNSISGenerator.cxx
+++ b/Source/CPack/cmCPackNSISGenerator.cxx
@@ -337,6 +337,7 @@ int cmCPackNSISGenerator::InitializeInternal()
     << std::endl);
   std::vector<std::string> path;
   std::string nsisPath;
+  bool gotRegValue = true;
 
 #ifdef _WIN32
   if ( !cmsys::SystemTools::ReadRegistryValue(
@@ -346,24 +347,37 @@ int cmCPackNSISGenerator::InitializeInternal()
     if ( !cmsys::SystemTools::ReadRegistryValue(
         "HKEY_LOCAL_MACHINE\\SOFTWARE\\NSIS", nsisPath) )
       {
-      cmCPackLogger
-        (cmCPackLog::LOG_ERROR,
-         "Cannot find NSIS registry value. This is usually caused by NSIS "
-         "not being installed. Please install NSIS from "
-         "http://nsis.sourceforge.net"
-         << std::endl);
-      return 0;
+      gotRegValue = false;
       }
     }
-  path.push_back(nsisPath);
+
+  if (gotRegValue)
+    {
+    path.push_back(nsisPath);
+    }
 #endif
+
   nsisPath = cmSystemTools::FindProgram("makensis", path, false);
+
   if ( nsisPath.empty() )
     {
-    cmCPackLogger(cmCPackLog::LOG_ERROR, "Cannot find NSIS compiler"
+    cmCPackLogger(cmCPackLog::LOG_ERROR,
+      "Cannot find NSIS compiler makensis: likely it is not installed, "
+      "or not in your PATH"
       << std::endl);
+
+    if (!gotRegValue)
+      {
+      cmCPackLogger(cmCPackLog::LOG_ERROR,
+         "Could not read NSIS registry value. This is usually caused by "
+         "NSIS not being installed. Please install NSIS from "
+         "http://nsis.sourceforge.net"
+         << std::endl);
+      }
+
     return 0;
     }
+
   std::string nsisCmd = "\"" + nsisPath + "\" " NSIS_OPT "VERSION";
   cmCPackLogger(cmCPackLog::LOG_VERBOSE, "Test NSIS version: "
     << nsisCmd.c_str() << std::endl);