Merge pull request #5 from PlasmaFAIR/bugfix/type-of-zero-length-arrays

Error on creating fixed zero-length dimensions

CMakeLists.txt

@@ -73,6 +73,16 @@ neasy-f, then disable source generation with NEASYF_GENERATE_SOURCE=off.")
     )
 endif()
 
+# Add some extra flags when compiling in debug mode
+target_compile_options(neasyf PRIVATE
+  $<$<CONFIG:Debug>:
+    $<$<Fortran_COMPILER_ID:GNU>:
+      -g -Wall -fimplicit-none -fbounds-check >
+    $<$<Fortran_COMPILER_ID:Intel>:
+      -g -implicitnone -warn all -nogen-interfaces -CB -traceback >
+    >
+  )
+
 ##################################################
 # Dependencies
 

README.md

@@ -68,6 +68,17 @@ netCDF4 files, and so requires netCDF to have been built with HDF5.
 
 Tested with gfortran 11 and netCDF-Fortran 4.5.3.
 
+Known Issues
+------------
+
+- gfortran has a bug when passing slices of arrays of derived types:
+  trying to write `some_array%member` will result in the wrong values
+  getting written. To workaround this, copy `some_array%member` into a
+  temporary variable and pass that to `neasyf_write`
+
+- Creating fixed zero-length variables or dimensions is not possible,
+  as netCDF uses `size = 0` to represent unlimited dimensions
+
 Compilation
 -----------
 

src/neasyf.f90

@@ -763,7 +763,7 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
     !> NetCDF ID of the parent group/file
     integer, intent(in) :: parent_id
     !> Coordinate values
-    class(*), dimension(:), optional, intent(in) :: values
+    class(*), dimension(:), optional, target, intent(in) :: values
     !> Size of the dimension if values isn't specified
     integer, optional, intent(in) :: dim_size
     !> NetCDF ID of the dimension
@@ -777,12 +777,11 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
     !> Is this dimension unlimited?
     logical, optional, intent(in) :: unlimited
 
-    integer(nf_kind) :: nf_type
     integer :: status
     integer(nf_kind) :: dim_id, var_id
     integer :: i
     integer :: local_size
-    integer, dimension(:), allocatable :: local_values
+    class(*), dimension(:), pointer :: local_values
     logical :: local_unlimited
 
     if (present(values) .and. present(dim_size)) then
@@ -821,12 +820,10 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
     ! initial size of the dimension
     if (present(values)) then
       local_size = size(values)
-      nf_type = neasyf_type(values)
-      ! TODO: check if nf_type indicates a derived type
+      local_values => values
     else if (present(dim_size)) then
       local_size = dim_size
-      local_values = [(i, i=1, dim_size)]
-      nf_type = neasyf_type(local_values)
+      allocate(local_values, source=[(i, i=1, dim_size)])
     end if
 
     ! Setting the dimension to be unlimited overrides the size
@@ -842,6 +839,11 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
            &Either pass one of 'values' or 'dim_size', or set 'unlimited=.true.'"
     end if
 
+    if (local_size == 0 .and. .not. local_unlimited) then
+      error stop "neasyf_dim: Dimension does not exist, and initial size is 0. &
+           &If you're trying to create an unlimited dimension, pass 'unlimited=.true.' instead"
+    end if
+
     status = nf90_def_dim(parent_id, name, local_size, dim_id)
     call neasyf_error(status, dim=name, dimid=dim_id, message="creating dimension")
 
@@ -858,16 +860,15 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
       return
     end if
 
-    ! We could avoid the duplicated call here by copying the values into an allocatable class(*)
-    if (present(values)) then
-      call neasyf_write(parent_id, name, values, dim_ids=[dim_id], units=units, long_name=long_name, varid=var_id)
-    else
-      call neasyf_write(parent_id, name, local_values, dim_ids=[dim_id], units=units, long_name=long_name, varid=var_id)
-    end if
+    call neasyf_write(parent_id, name, local_values, dim_ids=[dim_id], units=units, long_name=long_name, varid=var_id)
 
     if (present(varid)) then
       varid = var_id
     end if
+
+    ! If we allocated local_values, best free the memory. Note that
+    ! `allocated(local_values)` doesn't work here, because Fortran.
+    if (.not. present(values) .and. present(dim_size)) deallocate(local_values)
   end subroutine neasyf_dim
 
   subroutine neasyf_write_scalar(parent_id, name, values, dim_ids, dim_names, units, long_name, start)

src/neasyf.in.f90

@@ -323,7 +323,7 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
     !> NetCDF ID of the parent group/file
     integer, intent(in) :: parent_id
     !> Coordinate values
-    class(*), dimension(:), optional, intent(in) :: values
+    class(*), dimension(:), optional, target, intent(in) :: values
     !> Size of the dimension if values isn't specified
     integer, optional, intent(in) :: dim_size
     !> NetCDF ID of the dimension
@@ -337,12 +337,11 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
     !> Is this dimension unlimited?
     logical, optional, intent(in) :: unlimited
 
-    integer(nf_kind) :: nf_type
     integer :: status
     integer(nf_kind) :: dim_id, var_id
     integer :: i
     integer :: local_size
-    integer, dimension(:), allocatable :: local_values
+    class(*), dimension(:), pointer :: local_values
     logical :: local_unlimited
 
     if (present(values) .and. present(dim_size)) then
@@ -381,12 +380,10 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
     ! initial size of the dimension
     if (present(values)) then
       local_size = size(values)
-      nf_type = neasyf_type(values)
-      ! TODO: check if nf_type indicates a derived type
+      local_values => values
     else if (present(dim_size)) then
       local_size = dim_size
-      local_values = [(i, i=1, dim_size)]
-      nf_type = neasyf_type(local_values)
+      allocate(local_values, source=[(i, i=1, dim_size)])
     end if
 
     ! Setting the dimension to be unlimited overrides the size
@@ -402,6 +399,11 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
            &Either pass one of 'values' or 'dim_size', or set 'unlimited=.true.'"
     end if
 
+    if (local_size == 0 .and. .not. local_unlimited) then
+      error stop "neasyf_dim: Dimension does not exist, and initial size is 0. &
+           &If you're trying to create an unlimited dimension, pass 'unlimited=.true.' instead"
+    end if
+
     status = nf90_def_dim(parent_id, name, local_size, dim_id)
     call neasyf_error(status, dim=name, dimid=dim_id, message="creating dimension")
 
@@ -418,16 +420,15 @@ subroutine neasyf_dim(parent_id, name, values, dim_size, dimid, varid, units, lo
       return
     end if
 
-    ! We could avoid the duplicated call here by copying the values into an allocatable class(*)
-    if (present(values)) then
-      call neasyf_write(parent_id, name, values, dim_ids=[dim_id], units=units, long_name=long_name, varid=var_id)
-    else
-      call neasyf_write(parent_id, name, local_values, dim_ids=[dim_id], units=units, long_name=long_name, varid=var_id)
-    end if
+    call neasyf_write(parent_id, name, local_values, dim_ids=[dim_id], units=units, long_name=long_name, varid=var_id)
 
     if (present(varid)) then
       varid = var_id
     end if
+
+    ! If we allocated local_values, best free the memory. Note that
+    ! `allocated(local_values)` doesn't work here, because Fortran.
+    if (.not. present(values) .and. present(dim_size)) deallocate(local_values)
   end subroutine neasyf_dim
 
   subroutine neasyf_write_scalar(parent_id, name, values, dim_ids, dim_names, units, long_name, start)