cmListCommand: Handle invalid FOR selector ranges Fixes crashes involving invalid ranges specified in list(TRANSFORM ... FOR ...) calls. * Report error when step is not positive * Report error when start is after stop Fixes: #22985

diff --git a/Source/cmListCommand.cxx b/Source/cmListCommand.cxx
index b358327..56345df 100644
--- a/Source/cmListCommand.cxx
+++ b/Source/cmListCommand.cxx

@@ -678,6 +678,14 @@
     this->Start = this->NormalizeIndex(this->Start, count);
     this->Stop = this->NormalizeIndex(this->Stop, count);
 
+    // Does stepping move us further from the end?
+    if (this->Start > this->Stop) {
+      throw transform_error(
+        cmStrCat("sub-command TRANSFORM, selector FOR "
+                 "expects <start> to be no greater than <stop> (",
+                 this->Start, " > ", this->Stop, ")"));
+    }
+
     // compute indexes
     auto size = (this->Stop - this->Start + 1) / this->Step;
     if ((this->Stop - this->Start + 1) % this->Step != 0) {
@@ -1026,9 +1034,10 @@
         }
       }
 
-      if (step < 0) {
+      if (step <= 0) {
         status.SetError("sub-command TRANSFORM, selector FOR expects "
-                        "non negative numeric value for <step>.");
+                        "positive numeric value for <step>.");
+        return false;
       }
 
       command.Selector =

diff --git a/Tests/RunCMake/list/RunCMakeTest.cmake b/Tests/RunCMake/list/RunCMakeTest.cmake
index c11891c..eb43ee0 100644
--- a/Tests/RunCMake/list/RunCMakeTest.cmake
+++ b/Tests/RunCMake/list/RunCMakeTest.cmake

@@ -77,6 +77,9 @@
 run_cmake(TRANSFORM-Selector-FOR-TooManyArguments)
 run_cmake(TRANSFORM-Selector-FOR-BadArgument)
 run_cmake(TRANSFORM-Selector-FOR-InvalidIndex)
+run_cmake(TRANSFORM-Selector-FOR-ZeroStepArgument)
+run_cmake(TRANSFORM-Selector-FOR-NegativeStepArgument)
+run_cmake(TRANSFORM-Selector-FOR-BackwardsRange)
 # 'output' oriented tests
 run_cmake(TRANSFORM-Output-OUTPUT_VARIABLE-NoArguments)
 run_cmake(TRANSFORM-Output-OUTPUT_VARIABLE-TooManyArguments)

diff --git a/Tests/RunCMake/list/TRANSFORM-Selector-FOR-BackwardsRange-result.txt b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-BackwardsRange-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-BackwardsRange-result.txt

@@ -0,0 +1 @@
+1

diff --git a/Tests/RunCMake/list/TRANSFORM-Selector-FOR-BackwardsRange-stderr.txt b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-BackwardsRange-stderr.txt
new file mode 100644
index 0000000..1acdc15
--- /dev/null
+++ b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-BackwardsRange-stderr.txt

@@ -0,0 +1,5 @@
+^CMake Error at TRANSFORM-Selector-FOR-BackwardsRange.cmake:2 \(list\):
+  list sub-command TRANSFORM, selector FOR expects <start> to be no greater
+  than <stop> \(2 > 1\)
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)$

diff --git a/Tests/RunCMake/list/TRANSFORM-Selector-FOR-BackwardsRange.cmake b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-BackwardsRange.cmake
new file mode 100644
index 0000000..761c187
--- /dev/null
+++ b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-BackwardsRange.cmake

@@ -0,0 +1,2 @@
+set(mylist alpha bravo charlie)
+list(TRANSFORM mylist TOUPPER FOR 2 1)

diff --git a/Tests/RunCMake/list/TRANSFORM-Selector-FOR-NegativeStepArgument-result.txt b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-NegativeStepArgument-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-NegativeStepArgument-result.txt

@@ -0,0 +1 @@
+1

diff --git a/Tests/RunCMake/list/TRANSFORM-Selector-FOR-NegativeStepArgument-stderr.txt b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-NegativeStepArgument-stderr.txt
new file mode 100644
index 0000000..b9845a7
--- /dev/null
+++ b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-NegativeStepArgument-stderr.txt

@@ -0,0 +1,5 @@
+^CMake Error at TRANSFORM-Selector-FOR-NegativeStepArgument.cmake:2 \(list\):
+  list sub-command TRANSFORM, selector FOR expects positive numeric value for
+  <step>.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)$

diff --git a/Tests/RunCMake/list/TRANSFORM-Selector-FOR-NegativeStepArgument.cmake b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-NegativeStepArgument.cmake
new file mode 100644
index 0000000..0876512
--- /dev/null
+++ b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-NegativeStepArgument.cmake

@@ -0,0 +1,2 @@
+set(mylist alpha bravo charlie)
+list(TRANSFORM mylist TOUPPER FOR 0 2 -1)

diff --git a/Tests/RunCMake/list/TRANSFORM-Selector-FOR-ZeroStepArgument-result.txt b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-ZeroStepArgument-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-ZeroStepArgument-result.txt

@@ -0,0 +1 @@
+1

diff --git a/Tests/RunCMake/list/TRANSFORM-Selector-FOR-ZeroStepArgument-stderr.txt b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-ZeroStepArgument-stderr.txt
new file mode 100644
index 0000000..e8be4f1
--- /dev/null
+++ b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-ZeroStepArgument-stderr.txt

@@ -0,0 +1,5 @@
+^CMake Error at TRANSFORM-Selector-FOR-ZeroStepArgument.cmake:2 \(list\):
+  list sub-command TRANSFORM, selector FOR expects positive numeric value for
+  <step>.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)$

diff --git a/Tests/RunCMake/list/TRANSFORM-Selector-FOR-ZeroStepArgument.cmake b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-ZeroStepArgument.cmake
new file mode 100644
index 0000000..7b14eb6
--- /dev/null
+++ b/Tests/RunCMake/list/TRANSFORM-Selector-FOR-ZeroStepArgument.cmake

@@ -0,0 +1,2 @@
+set(mylist alpha bravo charlie)
+list(TRANSFORM mylist TOUPPER FOR 0 2 0)