Change package existence logic based on exist3nce of Dependencies.cma…

…ke file (trilinos/Trilinos#11976)

This fixes cases where a dirty/incomplete source directory for a package
remains but does not contain the Dependencies.cmake file.  This was a use case
I hit while experimenting with how to fix trilinos/Trilinos#11976.

This replaces a temp commit made to the Trilinos 'develop' branch.

test/core/ExamplesUnitTests/TribitsExampleProject_Tests.cmake

@@ -670,6 +670,12 @@ tribits_add_advanced_test( TribitsExampleProject_NoFortran_reduced_tarball
       -DTribitsExProj_ASSERT_DEFINED_DEPENDENCIES=OFF
       ../tribitsexproj-1.1-Source
     PASS_REGULAR_EXPRESSION_ALL
+      "CMake Warning at .*/tribits/core/package_arch/TribitsProcessPackagesAndDirsLists.cmake"
+      "MixedLang: Package base directory"
+      "'.*/tribitsexproj-1.1-Source/packages/mixed_lang'"
+      "exists but the dependencies file"
+      "'.*/tribitsexproj-1.1-Source/packages/mixed_lang/cmake/Dependencies.cmake'"
+      "does [*]NOT[*] exist. Package is being ignored anyway."
       "Final set of enabled top-level packages:  SimpleCxx WithSubpackages 2"
       "Final set of enabled packages:  SimpleCxx WithSubpackagesA WithSubpackagesB WithSubpackages 4"
       "Final set of non-enabled top-level packages:  0"
@@ -2783,7 +2789,7 @@ tribits_add_advanced_test( TribitsExampleProject_InsertedPkg
   XHOSTTYPE Darwin
 
   TEST_0
-    MESSAGE "Copy TribitsExampleProject so that we can copy in ExteranlPkg."
+    MESSAGE "Copy TribitsExampleProject so that we can copy in ExternalPkg."
     CMND cp
     ARGS -r ${${PROJECT_NAME}_TRIBITS_DIR}/examples/TribitsExampleProject .
 
@@ -2807,7 +2813,7 @@ tribits_add_advanced_test( TribitsExampleProject_InsertedPkg
       -DInsertedPkg_ALLOW_MISSING_EXTERNAL_PACKAGE=FALSE
       .
     PASS_REGULAR_EXPRESSION_ALL
-      "Error, the package InsertedPkg directory .+/TribitsExampleProject/InsertedPkg does not exist!"
+      "Error, the package InsertedPkg dependencies file '.+/TribitsExampleProject/InsertedPkg/cmake/Dependencies.cmake' does [*]NOT[*] exist!"
       "CMake Error at .+/TribitsProcessPackagesAndDirsLists.cmake:[0-9]+ [(]message[)]:"
       "Configuring incomplete, errors occurred!"
 

tribits/CHANGELOG.md

@@ -2,6 +2,18 @@
 ChangeLog for TriBITS
 ----------------------------------------
 
+## 2023-06-22:
+
+* **Added:** Packages are now determined to be missing if their dependencies
+  file `<packageDir>/cmake/Dependencies.cmake` is missing.  If the package
+  directory `<packageDir>` exists but the dependencies file is missing, the
+  package is determined to be missing but a warning is printed.  (This expands
+  behavior to gracefully deal with a situation where a package source
+  directory is only partially removed, such as with `git rm -r <packageDir>`,
+  but the base directory still exists.  Therefore, this allows the project to
+  gracefully configure with the package being considered missing and avoids a
+  fatal error in this case.)
+
 ## 2023-06-02:
 
 * **Added/Deprecated:** External packages/TPLs can now be (and should be)

tribits/core/package_arch/TribitsProcessPackagesAndDirsLists.cmake

@@ -535,7 +535,8 @@ macro(tribits_process_packages_and_dirs_lists  REPOSITORY_NAME  REPOSITORY_DIR)
 
       endif()
 
-      if (EXISTS ${PACKAGE_ABS_DIR})
+      set(packageDependenciesFile "${PACKAGE_ABS_DIR}/cmake/Dependencies.cmake")
+      if (EXISTS "${packageDependenciesFile}")
         set(PACKAGE_EXISTS TRUE)
       else()
         set(PACKAGE_EXISTS FALSE)
@@ -557,9 +558,14 @@ macro(tribits_process_packages_and_dirs_lists  REPOSITORY_NAME  REPOSITORY_DIR)
         )
         message(
           "\n***"
-          "\n*** Error, the package ${TRIBITS_PACKAGE} directory ${PACKAGE_ABS_DIR} does not exist!"
+          "\n*** Error, the package ${TRIBITS_PACKAGE} dependencies file"
+	    " '${packageDependenciesFile}' does *NOT* exist!"
           "\n***\n" )
         message(FATAL_ERROR "Stopping due to above error!")
+      elseif((NOT PACKAGE_EXISTS) AND (EXISTS "${PACKAGE_ABS_DIR}"))
+        message(WARNING "${TRIBITS_PACKAGE}: Package base directory '${PACKAGE_ABS_DIR}'"
+	  " exists but the dependencies file '${packageDependenciesFile}' does *NOT*"
+	  " exist!  Package is being ignored anyway!")
       endif()
 
       if (PACKAGE_EXISTS OR ${PROJECT_NAME}_IGNORE_PACKAGE_EXISTS_CHECK)

tribits/core/package_arch/TribitsReadDepsFilesCreateDepsGraph.cmake

@@ -182,8 +182,7 @@ macro(tribits_read_all_package_deps_files_create_deps_graph)
   set(${PROJECT_NAME}_DEFINED_INTERNAL_PACKAGES "") # Packages and subpackages
 
   foreach(TRIBITS_PACKAGE  IN LISTS ${PROJECT_NAME}_DEFINED_INTERNAL_TOPLEVEL_PACKAGES)
-    tribits_read_toplevel_package_deps_files_add_to_graph(${TRIBITS_PACKAGE}
-      ${${TRIBITS_PACKAGE}_REL_SOURCE_DIR})
+    tribits_read_toplevel_package_deps_files_add_to_graph(${TRIBITS_PACKAGE})
   endforeach()
 
   list(LENGTH ${PROJECT_NAME}_DEFINED_INTERNAL_PACKAGES