Incorrect results when subtracting two long numbers

[dburkat]

Describe the bug
A bug when doing the subtraction math operations on long number (e.g. timestamps with nanosecond precision).

To Reproduce

$ echo '{"ts_1": 1701833040235520606, "ts_2": 1701833040235501418}' | jq '{difference: (.ts_1 - .ts_2)}'
{
  "difference": 19200
}

Expected behavior
The expected result is:
1701833040235520606 - 1701833040235501418 = 19188

I noticed that the actual result that we get matches up with:
1701833040235520600 - 1701833040235501400 = 19200
So the timestamps are truncated to the hundredths.

Environment (please complete the following information):

• macOS (Ventura 13.6.2)
• jq version 1.7.1

Additional context
I know that jq version 1.7 had a fix to display long numbers correctly. Before version 1.7 the nanoseconds timestamps would get displayed incorrectly . For example 1701833040235501418 would be displayed as 1701833040235501300.

[wader]

Hi, this is expected at the moment and and there is currently no plan on changing it. See #2962 for similar issue. Note that jq 1.7 an 1.7.1 truncates a bit differently. jq 1.7.1 was changed to truncate more similar to other language implementations:

$ node -p '1701833040235520606-1701833040235501418'
19200

If you want to use a jq implementation with big integer operator support you can try https://github.com/itchyny/gojq

[dburkat]

Thank you very much for the quick response.