The CMake language implicitly flattens lists so a ";" in a list element
must be escaped with a backslash. List expansion removes backslashes
escaping semicolons to leave raw semicolons in the values. Teach
ExternalData_Add_Test and ExternalData_Expand_Arguments to re-escape
semicolons found in list elements so the resulting argument lists work
as if constructed directly by the set() command.
For example:
ExternalData_Add_Test(Data NAME test1 COMMAND ... "a\\;b")
ExternalData_Expand_Arguments(Data args2 "c\\;d")
add_test(NAME test2 COMMAND ... ${args2})
should be equivalent to
set(args1 "a\\;b")
add_test(NAME test1 COMMAND ... ${args1})
set(args2 "c\\;d")
add_test(NAME test2 COMMAND ... ${args2})
which is equivalent to
add_test(NAME test1 COMMAND ... "a;b")
add_test(NAME test2 COMMAND ... "c;d")
Note that it is not possible to make ExternalData_Add_Test act exactly
like add_test when quoted arguments contain semicolons because the CMake
language flattens lists when constructing function ARGN values. This
re-escape approach at least allows test arguments to have semicolons.
While at it, teach ExternalData APIs to not transform "DATA{...;...}"
arguments because the contained semicolons are non-sensical.
Suggested-by: Jean-Christophe Fillion-Robin <jchris.fillionr@kitware.com>
Brad King