instrumentation: Test shell redirection in instrumented custom commands

Issue: #27610

Tests/RunCMake/Instrumentation/RunCMakeTest.cmake

@@ -109,7 +109,7 @@ function(instrument test)
       "${RunCMake_TEST_BINARY_DIR}/cmake-command-workflow.cmake"
       @ONLY
     )
-    foreach(f IN ITEMS CMakeLists.txt main.cxx lib.cxx lib.h)
+    foreach(f IN ITEMS CMakeLists.txt main.cxx lib.cxx lib.h shell_redirect.txt)
       configure_file(
         "${RunCMake_TEST_SOURCE_DIR}/${f}"
         "${RunCMake_TEST_BINARY_DIR}/${f}"

Tests/RunCMake/Instrumentation/check-data-dir.cmake

@@ -88,7 +88,7 @@ foreach(snippet IN LISTS snippets)
       endif()
       json_missing_key("${snippet}" "${contents}" target)
     # unrecognized outputs
-    else()
+    elseif (NOT outputs MATCHES "shell_redirect\\.out")
       json_error("${snippet}" "Custom command has unexpected outputs\n${outputs}")
     endif()
   endif()
@@ -188,6 +188,10 @@ endif()
 if (ARGS_TEST AND NOT EXISTS ${RunCMake_TEST_BINARY_DIR}/Testing)
   add_error("ctest --instrument launcher failed to test the project")
 endif()
+# Ensure shell_redirect command ran successfully
+if (ARGS_BUILD AND NOT EXISTS ${RunCMake_TEST_BINARY_DIR}/shell_redirect.out)
+  add_error("custom command with shell redirection did not run")
+endif()
 
 # Look for build snippet, which may not appear immediately
 if (ARGS_BUILD_MAKE_PROGRAM)

Tests/RunCMake/Instrumentation/cmake-command-data-build-stdout.txt

@@ -0,0 +1 @@
+Redirect from shell in custom command

Tests/RunCMake/Instrumentation/project/CMakeLists.txt

@@ -15,10 +15,30 @@ add_custom_command(
   COMMAND ${CMAKE_COMMAND} -E true
   OUTPUT output1 output2
 )
+
+file(COPY_FILE shell_redirect.txt ${CMAKE_CURRENT_BINARY_DIR}/shell_redirect.in)
+if(CMAKE_GENERATOR STREQUAL "Watcom WMake")
+  # Watcom WMake does not seem to understand shell redirection.
+  add_custom_command(
+    OUTPUT shell_redirect.out
+    VERBATIM
+    COMMAND ${CMAKE_COMMAND} -E cat shell_redirect.in
+    COMMAND ${CMAKE_COMMAND} -E touch shell_redirect.out
+  )
+else()
+  add_custom_command(
+    OUTPUT shell_redirect.out
+    VERBATIM
+    COMMAND ${CMAKE_COMMAND} -E cat - < shell_redirect.in
+    COMMAND ${CMAKE_COMMAND} -E echo "> operator" > shell_redirect.out
+    COMMAND ${CMAKE_COMMAND} -E echo ">> operator" >> shell_redirect.out
+  )
+endif()
+
 set_property(SOURCE output1 output2 PROPERTY SYMBOLIC 1)
 add_custom_target(customTarget ALL
   COMMAND ${CMAKE_COMMAND} -E true
-  DEPENDS output1
+  DEPENDS output1 shell_redirect.out
 )
 add_test(NAME test COMMAND $<TARGET_FILE:main>)
 install(TARGETS main)

Tests/RunCMake/Instrumentation/project/shell_redirect.txt

@@ -0,0 +1 @@
+Redirect from shell in custom command