[PATCH] Crash fix in add_single_dive. No writing to dive_table.dives[-1]

[Lubomir I. Ivanov]

On 25 November 2015 at 20:01, K. "pestophagous" Heller
<pestophagous at gmail.com> wrote:
> On Wed, Nov 25, 2015 at 6:53 AM, Lubomir I. Ivanov <neolit123 at gmail.com> wrote:
>>
>> currently add_single_dive() assumes a safe index.
>> i think that add_single_dive() should not be touched, but instead the
>> mobile app should be fixed (models bug?).
>>
>
> That sounds reasonable, but i would mention the following:
>
> 1. if add_single_dive is going to assume a safe index, then we should
> add an assert. an assertion failure would have been preferable to
> varied and mysterious crashes after the call.
>
> 2. the ability to call with -1 is also a feature. currently, if you
> want to add a dive to the *front* of the list, you pass 0.  But if you
> want to add it to the *end* of the list, you need to know the size of
> the table (so you can pass the table size as your targeted insertion
> point).  Passing 0 to mean "prepend" does not require knowledge of the
> current table size.  So, using -1 as a shorthand for "append" provides
> a similar feature, then. no need to know the table size.
>

it's probably better to have the feature, over the assert().
then the mobile app should make sure if it really wants to add to the
back of the list with a negative value.

lubomir
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