To reproduce this bug:
In a new spreadsheet, start the numbers in a column as follows: 1.0, 1.1, 1.2, 1.3 and then select all of them and drag so as to autofill the rows after the last number. As expected, Calc autofills them as 1.4, 1.5, 1.6, 1.7, etc.
Now, try the exact same thing but starting with a number other than 1. Say, 3.0, 3.1, 3.2, 3.3, etc. Calc does not autofill the column as 3.4, 3.5, 3.6, etc. Instead, it fills as 4.0, 4.1, 4.2, 4.3, 5.0, 5.1, 5.2, 5.3, 6.0, etc.
[Reproducible] with "LibreOffice 3.4.0RC1 – WIN7 Home Premium (64bit) German UI [OOO340m1 (Build:11)]"
Seems to be a very old bug, I also see it in OOo 1.1.4, 3.1.1, 3.4dev
I also see some curious side effects, pls. see attached spreadsheet. Numbers until row 10 are source, starting with 11 is result of auto fill using fill handle with all cells containing numbers marked when starting auto fill.
Blue numbers have been created by manual input (color added after autofill), black numbers in rows with row number smaller than 11 have been created by a calculation.
Column A is expected behavior
Column B shows wrong behavior due to report
Column D: I typed 3.1, 3.2 into D7:D8, then I used autofill handle to fill
D9:D10. Now D7:D10 looks as B7:B10, but result is completely
different, here autofill works as expected with autofill D7:D10 using
handle to fill to D11:D14
Please feel free to reassign if it's not your area!
Created attachment 46969 [details]
Sample Document, see Comment 1
Solved it by allowing the autofill increment calculation to have a bit more tolerance when checking that the increment between each cells is the same.
This has been a pure floating point problem.
Markus Mohrhard committed a patch related to this issue.
It has been pushed to "master":
autofill increment needs a bit more tolerance, fdo#37424