Merge topic 'ExternalData-repeat-file'

f9973166 ExternalData: Tolerate files duplicated across multiple targets

Modules/ExternalData.cmake

@@ -86,6 +86,10 @@ Module Functions
   in one of the paths specified in the ``ExternalData_OBJECT_STORES``
   variable.
 
+  Typically only one target is needed to manage all external data within
+  a project.  Call this function once at the end of configuration after
+  all data references have been processed.
+
 Module Variables
 ^^^^^^^^^^^^^^^^
 
@@ -394,8 +398,14 @@ function(ExternalData_add_target target)
 
   set(files "")
 
-  # Set "_ExternalData_FILE_${file}" for each output file to avoid duplicate
-  # rules.  Use local data first to prefer real files over content links.
+  # Set a "_ExternalData_FILE_${file}" variable for each output file to avoid
+  # duplicate entries within this target.  Set a directory property of the same
+  # name to avoid repeating custom commands with the same output in this directory.
+  # Repeating custom commands with the same output across directories or across
+  # targets in the same directory may be a race, but this is likely okay because
+  # we use atomic replacement of output files.
+  #
+  # Use local data first to prefer real files over content links.
 
   # Custom commands to copy or link local data.
   get_property(data_local GLOBAL PROPERTY _ExternalData_${target}_LOCAL)
@@ -405,6 +415,9 @@ function(ExternalData_add_target target)
     list(GET tuple 1 name)
     if(NOT DEFINED "_ExternalData_FILE_${file}")
       set("_ExternalData_FILE_${file}" 1)
+      get_property(added DIRECTORY PROPERTY "_ExternalData_FILE_${file}")
+      if(NOT added)
+        set_property(DIRECTORY PROPERTY "_ExternalData_FILE_${file}" 1)
         add_custom_command(
           COMMENT "Generating ${file}"
           OUTPUT "${file}"
@@ -415,6 +428,7 @@ function(ExternalData_add_target target)
                                    -P ${_ExternalData_SELF}
           MAIN_DEPENDENCY "${name}"
           )
+      endif()
       list(APPEND files "${file}")
     endif()
   endforeach()
@@ -429,6 +443,9 @@ function(ExternalData_add_target target)
     set(stamp "${ext}-stamp")
     if(NOT DEFINED "_ExternalData_FILE_${file}")
       set("_ExternalData_FILE_${file}" 1)
+      get_property(added DIRECTORY PROPERTY "_ExternalData_FILE_${file}")
+      if(NOT added)
+        set_property(DIRECTORY PROPERTY "_ExternalData_FILE_${file}" 1)
         add_custom_command(
           # Users care about the data file, so hide the hash/timestamp file.
           COMMENT "Generating ${file}"
@@ -446,6 +463,7 @@ function(ExternalData_add_target target)
           # Update whenever the object hash changes.
           MAIN_DEPENDENCY "${name}${ext}"
           )
+      endif()
       list(APPEND files "${file}${stamp}")
     endif()
   endforeach()

Tests/Module/ExternalData/CMakeLists.txt

@@ -53,4 +53,5 @@ ExternalData_Add_Target(Data1)
 add_subdirectory(Data2)
 add_subdirectory(Data3)
 add_subdirectory(Data4)
+add_subdirectory(Data5)
 add_subdirectory(DataNoSymlinks)

Tests/Module/ExternalData/Data5/CMakeLists.txt

@@ -0,0 +1,22 @@
+# Test adding the same data file in multiple tests
+ExternalData_Add_Test(Data5.A
+  NAME Data5Check.A
+  COMMAND ${CMAKE_COMMAND}
+    -D Data5=DATA{../Data.dat}
+    -P ${CMAKE_CURRENT_SOURCE_DIR}/Data5Check.cmake
+  )
+ExternalData_Add_Target(Data5.A)
+ExternalData_Add_Test(Data5.B
+  NAME Data5Check.B
+  COMMAND ${CMAKE_COMMAND}
+    -D Data5=DATA{../Data.dat}
+    -P ${CMAKE_CURRENT_SOURCE_DIR}/Data5Check.cmake
+  )
+ExternalData_Add_Target(Data5.B)
+ExternalData_Add_Test(Data5.C
+  NAME Data5Check.C
+  COMMAND ${CMAKE_COMMAND}
+    -D Data5=DATA{../Data.dat}
+    -P ${CMAKE_CURRENT_SOURCE_DIR}/Data5Check.cmake
+  )
+ExternalData_Add_Target(Data5.C)

Tests/Module/ExternalData/Data5/Data5Check.cmake

@@ -0,0 +1,4 @@
+file(STRINGS "${Data5}" lines LIMIT_INPUT 1024)
+if(NOT "x${lines}" STREQUAL "xInput file already transformed.")
+  message(SEND_ERROR "Input file:\n  ${Data5}\ndoes not have expected content, but [[${lines}]]")
+endif()