Problem in Trial Balance report with stocks and multiple currencies

Sherlock Holmes sh025622 at gmail.com
Sun Aug 24 16:20:15 EDT 2025 

John,

Yes.  I have.  And I do think I understand both algorithms and their 
evolution.

Again, assuming the sign swap was necessary for "average cost", when the 
sign swap was first effectuated 17 years ago, it does not appear to have 
been applied on the first entry.   This code has been rewritten multiple 
times since then and the issue appears to have been replicated time 
after time.  I know it seems unlikely but have a look at the code.  What 
am I missing?

Regards,

Sherlock


On 8/24/25 12:43 PM, John Ralls wrote:
> Sherlock,
>
> Seems unlikely. Have you read through 
> https://bugs.gnucash.org/show_bug.cgi?id=797796, 
> https://bugs.gnucash.org/show_bug.cgi?id=775368, and 
> https://bugs.gnucash.org/show_bug.cgi?id=775368 (the latter two are 
> referenced in https://bugs.gnucash.org/show_bug.cgi?id=797796#c8) so 
> that you thoroughly understand the problem and the design of the 
> algorithm?
>
> Regards,
> John Ralls
>
>
>> On Aug 24, 2025, at 12:13, Sherlock Holmes <sh025622 at gmail.com> wrote:
>>
>> John,
>>
>> Here's where I'm at:  I suspect the initial "account" commodity list 
>> entry in the "average cost" algorithm has been a bit off since Oct 
>> 16, 2008.  It appears the share and value signs are supposed to be 
>> swapped on assignment to the "account" commodity list, but are not 
>> when the list is first created.  See the attached patch file.
>>
>> Thoughts?
>>
>> Regards,
>>
>> Sherlock
>>
>>
>> On 8/24/25 10:21 AM, Sherlock Holmes wrote:
>>>
>>> John,
>>>
>>> I'm still working it.  It appears to me that both algorithms may 
>>> have gone a bit awry sometime ago although the "average price" may 
>>> be okay. Specifically, the initial comm-list entry became an else 
>>> case which meant it needed to perform the assignments and, in the 
>>> "average cost", the sign handling doesn't
>>>
>>> My WAG was just that.  Just a quick check to see if I was in the 
>>> right area.
>>>
>>>
>>> Regards,
>>>
>>> Sherlock
>>>
>>>
>>> On 8/24/25 9:16 AM, John Ralls wrote:
>>>>  Sherlock,
>>>>
>>>> What’s this part for? It seems irrelevant to Chang Wang’s example 
>>>> as that doesn’t use trading accounts:
>>>> -
>>>> -       ;; However skip splits in trading accounts as these 
>>>> counterbalance
>>>> -       ;; the actual value and share amounts back to zero
>>>> -       ((eqv? (xaccAccountGetType (xaccSplitGetAccount (car 
>>>> comm-splits)))
>>>> -              ACCT-TYPE-TRADING)
>>>> -        (loop (cdr comm-splits)
>>>> -              sumlist))
>>>> I guess you did a bisect to arrive at the 2019 change date. There 
>>>> were 8 changes to gnc-commodity-utils.scm that day. Which one was 
>>>> the culprit?
>>>>
>>>> Regards,
>>>> John Ralls
>>>>
>>>>
>>>>> On Aug 23, 2025, at 20:18, Sherlock Holmes <sh025622 at gmail.com> wrote:
>>>>>
>>>>> I concur.
>>>>>
>>>>> There are significant differences in the implementation between 
>>>>> gnc:get-exchange-totals and gnc:get-exchange-cost-totals that I 
>>>>> believe are the root cause of the issue.  These differences appear 
>>>>> to date back to May 3, 2019.    As a WAG, I modified 
>>>>> gnc:get-exchange-cost-totals to match gnc:get-exchange-totals in 
>>>>> the attached patch and the issue you've raised appears to be 
>>>>> resolved.  I have not done any further testing,
>>>>>
>>>>> Regards,
>>>>>
>>>>> Sherlock
>>>>>
>>>>>
>>>>> On 8/23/25 2:20 PM, Chang Wang wrote:
>>>>>> Thanks for the reminder. I'll post to the user list in the future.
>>>>>> However, in the above example, there is no gain or loss due to 
>>>>>> currency exchange as the exchange rates are set to 1 so no 
>>>>>> currency gain/loss needs to be booked. And the price source is 
>>>>>> set to be Last up through report date instead of average cost. 
>>>>>> Therefore, I think these are different issues.
>>>>>>
>>>>>> On Sat, Aug 23, 2025 at 3:51 PM John Ralls <jralls at ceridwen.us> 
>>>>>> wrote:
>>>>>>
>>>>>>     Oddly I just told somebody on IRC the same answer:
>>>>>>     https://bugs.gnucash.org/show_bug.cgi?id=797796
>>>>>>
>>>>>>     Unless you’re willing to submit a PR, this is a user-list
>>>>>>     topic, so in the future please use gnucash-user instead of
>>>>>>     gnucash-devel.
>>>>>>
>>>>>>     Regards,
>>>>>>     John Ralls
>>>>>>
>>>>>>     > On Aug 23, 2025, at 1:43 PM, Chang Wang
>>>>>>     <wangchang327 at gmail.com> wrote:
>>>>>>     >
>>>>>>     > Hi all,
>>>>>>     > I noticed an issue with the Trial Balance report when using
>>>>>>     stock trading and multiple currencies. Even when transactions
>>>>>>     are balanced, the Trial Balance report appears to break due
>>>>>>     to incorrect calculation of unrealized gains.
>>>>>>     >
>>>>>>     > I've attached an uncompressed minimal example to illustrate
>>>>>>     the problem.
>>>>>>     >
>>>>>>     > Steps to reproduce:
>>>>>>     > Open the attached book.
>>>>>>     > Generate a Trial Balance report with reporting currency set
>>>>>>     to USD, price source set to Last up through report date, and
>>>>>>     enable Show Foreign Currencies and Exchange Rates.
>>>>>>     >
>>>>>>     > Observed behavior:
>>>>>>     > The report shows an Unrealized Gain of $20,800, which is
>>>>>>     incorrect.
>>>>>>     >
>>>>>>     > Expected behavior:
>>>>>>     > The Unrealized Gain should be $200.
>>>>>>     >
>>>>>>     > Explanation:
>>>>>>     > The example contains three transactions:
>>>>>>     > 1) 08/02/2025 - Buy one stock for 10,200 JPY.
>>>>>>     > 2) 08/03/2025 - Exchange 100,000 JPY for 100,000 USD.
>>>>>>     > 3) 08/04/2025 - Buy one stock for 10,400 JPY.
>>>>>>     >
>>>>>>     > The JPY/USD rate is fixed at 1 on all days, so there should
>>>>>>     be no realized or unrealized currency gains. Stock prices are
>>>>>>     set at 10X00 JPY on 08/0X/2025, where X = 1, 2, 3, 4.
>>>>>>     >
>>>>>>     > Therefore, in USD reporting currency, the Trial Balance
>>>>>>     should show unrealized gains as:
>>>>>>     > (10,400 * 2) - 10,200 - 10,400 = 200 JPY = 200 USD
>>>>>>     >
>>>>>>     > Notably, the Balance Sheet report does display the correct
>>>>>>     unrealized gain. And if transaction 3) or transaction 2) is
>>>>>>     removed, the Trial Balance turns out to be correct.
>>>>>>     >
>>>>>>     > I'm not familiar with Scheme, so I wasn't able to locate
>>>>>>     the problem in the source code. I also wasn't able to file a
>>>>>>     bug on Bugzilla, since the registration function appears to
>>>>>>     be broken.
>>>>>>     >
>>>>>>     > Thanks for your attention,
>>>>>>     > Chang
>>>>>>     > <tb.gnucash>_______________________________________________
>>>>>>
>>>>>>
>> <commodity-utilities.scm.patch>
>
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