expand global table size

[ab9rf]

need to remember to check and update this with each release

[myk002]

is there a regression test we could add that will fail the build if it's wrong?

[ab9rf]

Probably could be done with a lua script at runtime: just start at global_table[0] and iterate forward until .address is null; that index is the terminator, which Toady has guaranteed us will be immediately after the last entry.

[myk002]

I'll see if I can write a test like that

[myk002]

testing this:

-- validates that the size in df.globals.xml is correct
function test.global_table_size()
    local elem_size = df.global_table_entry:sizeof()
    local declared_arr_size = df.global.global_table:sizeof() // elem_size
    for i=0,declared_arr_size-2 do
        expect.true_(df._displace(df.global.global_table[0], i, elem_size).address,
            'nil address found in middle of global_table')
    end
    expect.false_(df._displace(df.global.global_table[0], declared_arr_size-1, elem_size).address,
        'nil *not* found at end of declared global-table')
end

[myk002]

version 2 of the test:

-- validates that the size in df.globals.xml is correct
function test.global_table_size()
    local elem_size = df.global_table_entry:sizeof()
    local declared_arr_size = df.global.global_table:sizeof() // elem_size
    for i=0,declared_arr_size-1 do
        expect.true_(df._displace(df.global.global_table[0], i, elem_size).address,
            'nil address found in middle of global_table at idx ' .. i)
    end
    if df._displace(df.global.global_table[0], declared_arr_size, elem_size).address then
        local idx_of_nil
        for i=declared_arr_size+1,declared_arr_size*2 do
            if not df._displace(df.global.global_table[0], i, elem_size).address then
                idx_of_nil = i
                break
            end
        end
        expect.fail('nil *not* found at end of declared global-table (idx ' .. declared_arr_size .. '); table size should be: ' .. idx_of_nil)
    end
end

output:

Check failed! nil *not* found at end of declared global-table (idx 366); table size should be: 379
  at ...eamapps/common/Dwarf Fortress/hack/scripts/test/core.lua:58

test failed: core:global_table_size

[myk002]

need to remember to check and update this with each release

you know just how to push my buttons

[ab9rf]

I will point out that attempting to read past the actual last element is UB, and so it's probably safer to scan the table until you find the terminator. This will identify its actual length. Then compare with what is declared; if different, fail.

If the declared length is greater than the actual length, reading that element will read unspecified memory.

[myk002]

good point. will fix

[myk002]

ok, the test correctly fails in https://github.com/DFHack/dfhack/actions/runs/12076775793
and passes when the df-structures ref is updated in https://github.com/DFHack/dfhack/actions/runs/12076789083