cmake: Replace old git tags if found.

Detect old badly formatted git tags we used in the user's git clone, and
if found delete all tags and fetch them from the origin.

Signed-off-by: Rafael Kitover <rkitover@gmail.com>

CMakeLists.txt

@@ -246,6 +246,46 @@ if(GIT_FOUND AND EXISTS "${CMAKE_SOURCE_DIR}/.git")
     # of files that depend on version.h
     include(GetGitRevisionDescription)
     get_git_head_revision(REFSPEC COMMITHASH)
+
+    # Make sure old tags are gone from all clones.
+    execute_process(
+        COMMAND ${GIT_EXECUTABLE} tag -l
+        OUTPUT_VARIABLE git_tags
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+        WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+    )
+
+    string(REGEX REPLACE ";"     "\\\\;" git_tags_lines "${git_tags}")
+    string(REGEX REPLACE "\r?\n" ";"     git_tags_lines "${git_tags_lines}")
+
+    set(found_old_tags FALSE)
+
+    foreach(tag ${git_tags_lines})
+        if(NOT tag MATCHES "^v[0-9]")
+            set(found_old_tags TRUE)
+            break()
+        endif()
+    endforeach()
+
+    if(found_old_tags)
+        # Delete all tags and fetch them from the origin.
+
+        foreach(tag ${git_tags_lines})
+            execute_process(
+                COMMAND ${GIT_EXECUTABLE} tag -d ${tag}
+                OUTPUT_QUIET
+                ERROR_QUIET
+                WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+            )
+        endforeach()
+
+        execute_process(
+            COMMAND ${GIT_EXECUTABLE} fetch --tags
+            OUTPUT_QUIET
+            ERROR_QUIET
+            WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+        )
+    endif()
 endif()
 
 # no git or no tags, use ChangeLog