BuildSystem: Add another revision.h setup "test-clause" (in case someone doesn't have a .hg dir or .hg_archival.txt)

- Set revision-ID to 0, and revision-hash to "Unknown archive", if an id/hash can not be properly detected.
  This should never happen unless the user has -deliberately deleted- the .hg directory and/or the .hg_archival.txt,
  or does not have the hg command in their command-path

--HG--
branch : trunk

1 files changed, 18 insertions, 7 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1311ca557ec..56c313c95e6 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -58,7 +58,6 @@ if( UNIX )
 endif()
 
 if(EXISTS ${CMAKE_SOURCE_DIR}/.hg_archival.txt)
-  set(hg_rev_id_str "Archive")
   file(READ
     ${CMAKE_SOURCE_DIR}/.hg_archival.txt hg_rev_hash_str
     LIMIT 10
@@ -67,9 +66,9 @@ if(EXISTS ${CMAKE_SOURCE_DIR}/.hg_archival.txt)
   )
   string(STRIP ${hg_rev_id_str} hg_rev_id_str)
   string(STRIP ${hg_rev_hash_str} hg_rev_hash_str)
+  set(hg_rev_id_str "Archive")
   set(hg_rev_id "0")
   set(hg_rev_hash ${hg_rev_hash_str})
-
 else()
   # Find revision ID and hash of the sourcetree
   execute_process(
@@ -77,20 +76,32 @@ else()
     WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
     OUTPUT_VARIABLE hg_rev_id_str
     OUTPUT_STRIP_TRAILING_WHITESPACE
-    ERROR_QUIET
   )
   execute_process(
     COMMAND hg id -i
     WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
     OUTPUT_VARIABLE hg_rev_hash_str
     OUTPUT_STRIP_TRAILING_WHITESPACE
-    ERROR_QUIET
   )
-  # Strip off excess strings (shows when the source is actually modified)
-  string(REPLACE "+" "" hg_rev_id ${hg_rev_id_str})
-  string(REPLACE "+" "" hg_rev_hash ${hg_rev_hash_str})
 endif()
 
+# Last minute check - ensure that we have a proper revision
+# If everything above fails (means the user has erased the mercurial revisional control directory, or runs archive and erased their .hg_archival.txt)
+if(NOT hg_rev_id_str)
+  message("")
+  message(STATUS "WARNING - No revision-information found - have you been tampering with the sources?")
+
+  # Ok, since we have no valid ways of finding/setting the revision, let's force some defaults
+  set(hg_rev_id_str "0")
+  set(hg_rev_id "0")
+  set(hg_rev_hash_str "Unknown archive")
+  set(hg_rev_hash "0")
+endif()
+
+# Strip off excess strings (shows when the source is actually modified)
+string(REPLACE "+" "" hg_rev_id ${hg_rev_id_str})
+string(REPLACE "+" "" hg_rev_hash ${hg_rev_hash_str})
+
 # Create the actual revision.h file from the above params
 configure_file(
   "${CMAKE_SOURCE_DIR}/revision.h.in.cmake"