From 6f2701abf60bc8c0aeed14e09adf28d59023da87 Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Tue, 10 Apr 2018 13:14:02 -0400
Subject: CPack: Fix crash on invalid generator name

In commit v3.11.0-rc1~68^2 (CPack: accept --trace and --trace-expand,
2017-12-09) a nullptr dereference was added that occurs when
`cpack -G NotAGenerator` is invoked.  Add the needed condition.

Fixes: #17900
---
 Source/CPack/cpack.cxx                                   |  8 ++++----
 Tests/RunCMake/CMakeLists.txt                            |  1 +
 Tests/RunCMake/CPackCommandLine/NotAGenerator-result.txt |  1 +
 Tests/RunCMake/CPackCommandLine/NotAGenerator-stderr.txt |  1 +
 Tests/RunCMake/CPackCommandLine/RunCMakeTest.cmake       | 10 ++++++++++
 5 files changed, 17 insertions(+), 4 deletions(-)
 create mode 100644 Tests/RunCMake/CPackCommandLine/NotAGenerator-result.txt
 create mode 100644 Tests/RunCMake/CPackCommandLine/NotAGenerator-stderr.txt
 create mode 100644 Tests/RunCMake/CPackCommandLine/RunCMakeTest.cmake

diff --git a/Source/CPack/cpack.cxx b/Source/CPack/cpack.cxx
index 507a10c..b6ff38b 100644
--- a/Source/CPack/cpack.cxx
+++ b/Source/CPack/cpack.cxx
@@ -350,16 +350,16 @@ int main(int argc, char const* const* argv)
         }
         if (parsed) {
           cpackGenerator = generators.NewGenerator(gen);
-          if (!cpackGenerator) {
+          if (cpackGenerator) {
+            cpackGenerator->SetTrace(trace);
+            cpackGenerator->SetTraceExpand(traceExpand);
+          } else {
             cmCPack_Log(&log, cmCPackLog::LOG_ERROR,
                         "Cannot initialize CPack generator: " << gen
                                                               << std::endl);
             parsed = 0;
           }
 
-          cpackGenerator->SetTrace(trace);
-          cpackGenerator->SetTraceExpand(traceExpand);
-
           if (parsed && !cpackGenerator->Initialize(gen, mf)) {
             cmCPack_Log(&log, cmCPackLog::LOG_ERROR,
                         "Cannot initialize the generator " << gen
diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index d5bd297..c52f44e 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -335,6 +335,7 @@ add_RunCMake_test(CommandLine -DCMAKE_SYSTEM_NAME=${CMAKE_SYSTEM_NAME})
 add_RunCMake_test(CommandLineTar)
 
 add_RunCMake_test(install)
+add_RunCMake_test(CPackCommandLine)
 add_RunCMake_test(CPackConfig)
 add_RunCMake_test(CPackInstallProperties)
 add_RunCMake_test(ExternalProject)
diff --git a/Tests/RunCMake/CPackCommandLine/NotAGenerator-result.txt b/Tests/RunCMake/CPackCommandLine/NotAGenerator-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/CPackCommandLine/NotAGenerator-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/CPackCommandLine/NotAGenerator-stderr.txt b/Tests/RunCMake/CPackCommandLine/NotAGenerator-stderr.txt
new file mode 100644
index 0000000..fe4e455
--- /dev/null
+++ b/Tests/RunCMake/CPackCommandLine/NotAGenerator-stderr.txt
@@ -0,0 +1 @@
+^CPack Error: Cannot initialize CPack generator: NotAGenerator
diff --git a/Tests/RunCMake/CPackCommandLine/RunCMakeTest.cmake b/Tests/RunCMake/CPackCommandLine/RunCMakeTest.cmake
new file mode 100644
index 0000000..991146c
--- /dev/null
+++ b/Tests/RunCMake/CPackCommandLine/RunCMakeTest.cmake
@@ -0,0 +1,10 @@
+include(RunCMake)
+set(RunCMake_TEST_TIMEOUT 60)
+
+file(WRITE "${RunCMake_BINARY_DIR}/NotAGenerator-build/CPackConfig.cmake" [[
+set(CPACK_PACKAGE_NAME "Test")
+set(CPACK_PACKAGE_VERSION "1")
+]])
+set(RunCMake_TEST_NO_CLEAN 1)
+run_cmake_command(NotAGenerator ${CMAKE_CPACK_COMMAND} -G NotAGenerator)
+unset(RunCMake_TEST_NO_CLEAN)
-- 
cgit v0.12