CPack: Restore support for custom package configuration templates

Refactoring in commit 98617f1be0 (Refactor: Move CPack internal files to
`Internal/CPack/` directory, 2019-07-09, v3.16.0-rc1~449^2) accidentally
changed the public-facing names of the templates.  The name passed to
`FindTemplate` is searched in `CMAKE_MODULE_PATH` and should not change.
Remove the `Internal/CPack/` prefix on the names added by that commit.
Teach `FindTemplate` to use our builtin default directly when the
public-facing name is not found in `CMAKE_MODULE_PATH`.

Fixes: #19979

6 files changed, 18 insertions, 9 deletions

diff --git a/Source/CPack/WiX/cmCPackWIXGenerator.cxx b/Source/CPack/WiX/cmCPackWIXGenerator.cxx
index 5fdbeab..e71a38f 100644
--- a/Source/CPack/WiX/cmCPackWIXGenerator.cxx
+++ b/Source/CPack/WiX/cmCPackWIXGenerator.cxx
@@ -610,7 +610,7 @@ std::string cmCPackWIXGenerator::GetRootFolderId() const
 
 bool cmCPackWIXGenerator::GenerateMainSourceFileFromTemplate()
 {
-  std::string wixTemplate = FindTemplate("Internal/CPack/WIX.template.in");
+  std::string wixTemplate = FindTemplate("WIX.template.in");
   if (GetOption("CPACK_WIX_TEMPLATE") != 0) {
     wixTemplate = GetOption("CPACK_WIX_TEMPLATE");
   }
diff --git a/Source/CPack/cmCPackGenerator.cxx b/Source/CPack/cmCPackGenerator.cxx
index 153f328..b7342fb 100644
--- a/Source/CPack/cmCPackGenerator.cxx
+++ b/Source/CPack/cmCPackGenerator.cxx
@@ -23,6 +23,7 @@
 #include "cmState.h"
 #include "cmStateSnapshot.h"
 #include "cmStringAlgorithms.h"
+#include "cmSystemTools.h"
 #include "cmVersion.h"
 #include "cmWorkingDirectory.h"
 #include "cmXMLSafe.h"
@@ -1262,7 +1263,17 @@ std::string cmCPackGenerator::FindTemplate(const char* name)
   cmCPackLogger(cmCPackLog::LOG_DEBUG,
                 "Look for template: " << (name ? name : "(NULL)")
                                       << std::endl);
+  // Search CMAKE_MODULE_PATH for a custom template.
   std::string ffile = this->MakefileMap->GetModulesFile(name);
+  if (ffile.empty()) {
+    // Fall back to our internal builtin default.
+    ffile = cmStrCat(cmSystemTools::GetCMakeRoot(), "/Modules/Internal/CPack/",
+                     name);
+    cmSystemTools::ConvertToUnixSlashes(ffile);
+    if (!cmSystemTools::FileExists(ffile)) {
+      ffile.clear();
+    }
+  }
   cmCPackLogger(cmCPackLog::LOG_DEBUG,
                 "Found template: " << ffile << std::endl);
   return ffile;
diff --git a/Source/CPack/cmCPackNSISGenerator.cxx b/Source/CPack/cmCPackNSISGenerator.cxx
index adea8ec..9bf72df 100644
--- a/Source/CPack/cmCPackNSISGenerator.cxx
+++ b/Source/CPack/cmCPackNSISGenerator.cxx
@@ -39,8 +39,7 @@ int cmCPackNSISGenerator::PackageFiles()
 {
   // TODO: Fix nsis to force out file name
 
-  std::string nsisInFileName =
-    this->FindTemplate("Internal/CPack/NSIS.template.in");
+  std::string nsisInFileName = this->FindTemplate("NSIS.template.in");
   if (nsisInFileName.empty()) {
     cmCPackLogger(cmCPackLog::LOG_ERROR,
                   "CPack error: Could not find NSIS installer template file."
@@ -48,7 +47,7 @@ int cmCPackNSISGenerator::PackageFiles()
     return false;
   }
   std::string nsisInInstallOptions =
-    this->FindTemplate("Internal/CPack/NSIS.InstallOptions.ini.in");
+    this->FindTemplate("NSIS.InstallOptions.ini.in");
   if (nsisInInstallOptions.empty()) {
     cmCPackLogger(cmCPackLog::LOG_ERROR,
                   "CPack error: Could not find NSIS installer options file."
diff --git a/Source/CPack/cmCPackOSXX11Generator.cxx b/Source/CPack/cmCPackOSXX11Generator.cxx
index cd65694..951c65f 100644
--- a/Source/CPack/cmCPackOSXX11Generator.cxx
+++ b/Source/CPack/cmCPackOSXX11Generator.cxx
@@ -240,7 +240,7 @@ bool cmCPackOSXX11Generator::CopyResourcePlistFile(
   const std::string& name, const std::string& dir,
   const char* outputFileName /* = 0 */, bool copyOnly /* = false */)
 {
-  std::string inFName = cmStrCat("Internal/CPack/CPack.", name, ".in");
+  std::string inFName = cmStrCat("CPack.", name, ".in");
   std::string inFileName = this->FindTemplate(inFName.c_str());
   if (inFileName.empty()) {
     cmCPackLogger(cmCPackLog::LOG_ERROR,
diff --git a/Source/CPack/cmCPackPKGGenerator.cxx b/Source/CPack/cmCPackPKGGenerator.cxx
index 3e1a51b..dae5ec9 100644
--- a/Source/CPack/cmCPackPKGGenerator.cxx
+++ b/Source/CPack/cmCPackPKGGenerator.cxx
@@ -49,7 +49,7 @@ std::string cmCPackPKGGenerator::GetPackageName(
 void cmCPackPKGGenerator::WriteDistributionFile(const char* metapackageFile)
 {
   std::string distributionTemplate =
-    this->FindTemplate("Internal/CPack/CPack.distribution.dist.in");
+    this->FindTemplate("CPack.distribution.dist.in");
   if (distributionTemplate.empty()) {
     cmCPackLogger(cmCPackLog::LOG_ERROR,
                   "Cannot find input file: " << distributionTemplate
@@ -300,7 +300,7 @@ bool cmCPackPKGGenerator::CopyResourcePlistFile(const std::string& name,
     outName = name.c_str();
   }
 
-  std::string inFName = cmStrCat("Internal/CPack/CPack.", name, ".in");
+  std::string inFName = cmStrCat("CPack.", name, ".in");
   std::string inFileName = this->FindTemplate(inFName.c_str());
   if (inFileName.empty()) {
     cmCPackLogger(cmCPackLog::LOG_ERROR,
diff --git a/Source/CPack/cmCPackSTGZGenerator.cxx b/Source/CPack/cmCPackSTGZGenerator.cxx
index bb0ed4f..a4a5e6f 100644
--- a/Source/CPack/cmCPackSTGZGenerator.cxx
+++ b/Source/CPack/cmCPackSTGZGenerator.cxx
@@ -27,8 +27,7 @@ int cmCPackSTGZGenerator::InitializeInternal()
 {
   this->SetOptionIfNotSet("CPACK_INCLUDE_TOPLEVEL_DIRECTORY", "0");
 
-  std::string inFile =
-    this->FindTemplate("Internal/CPack/CPack.STGZ_Header.sh.in");
+  std::string inFile = this->FindTemplate("CPack.STGZ_Header.sh.in");
   if (inFile.empty()) {
     cmCPackLogger(cmCPackLog::LOG_ERROR,
                   "Cannot find template file: " << inFile << std::endl);