diff options
Diffstat (limited to 'Modules/ExternalProject.cmake')
| -rw-r--r-- | Modules/ExternalProject.cmake | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake index 4a9809b..987b69a 100644 --- a/Modules/ExternalProject.cmake +++ b/Modules/ExternalProject.cmake @@ -2579,11 +2579,24 @@ function(_ep_write_command_script endif() if(genex_supported) - # Only written at generation phase + # Only written at generation phase. This will only change the file's + # timestamp if the contents change. file(GENERATE OUTPUT "${script_filename}" CONTENT "${script_content}") else() - # Written immediately, needed if script has to be invoked in configure phase - file(WRITE "${script_filename}" "${script_content}") + # Update the file immediately, needed if script has to be invoked in the + # configure phase (e.g. via FetchContent). We need to be careful to avoid + # updating the timestamp if the file contents don't change. The file(WRITE) + # command always updates the file, so avoid it if we don't need to call it. + set(doWrite TRUE) + if(EXISTS "${script_filename}") + file(READ "${script_filename}" existing_content) + if(existing_content STREQUAL script_content) + set(doWrite FALSE) + endif() + endif() + if(doWrite) + file(WRITE "${script_filename}" "${script_content}") + endif() endif() endfunction() @@ -3916,7 +3929,12 @@ function(_ep_do_preconfigure_steps_now name) if(NOT need_to_run) foreach(dep_file ${script_file} ${_EPdepends_${STEP}}) - if(NOT EXISTS ${dep_file} OR ${dep_file} IS_NEWER_THAN ${stamp_file}) + # IS_NEWER_THAN is also true if the timestamps are the same. On some + # file systems, we only have second resolution timestamps and the + # likelihood of having the same timestamp is high. Use the negative + # form to ensure we actually get a true "is newer than" test. + if(NOT EXISTS ${dep_file} OR + NOT ${stamp_file} IS_NEWER_THAN ${dep_file}) set(need_to_run TRUE) break() endif() |