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fix: LCM panicked due to overflow #11131

Merged
merged 4 commits into from
Jun 27, 2024
Merged

fix: LCM panicked due to overflow #11131

merged 4 commits into from
Jun 27, 2024

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jonahgao
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Which issue does this PR close?

Closes #11104.

Rationale for this change

  • Use checked_mul to detect multiplication overflow.
  • This PR also fixed the issue of LCM potentially returning a negative result.
DataFusion CLI v39.0.0

> select lcm(1, -9223372036854775808);
+-------------------------------------------+
| lcm(Int64(1),Int64(-9223372036854775808)) |
+-------------------------------------------+
| -9223372036854775808                      |
+-------------------------------------------+
1 row(s) fetched.

What changes are included in this PR?

Are these changes tested?

Yes

Are there any user-facing changes?

No

@github-actions github-actions bot added the sqllogictest SQL Logic Tests (.slt) label Jun 26, 2024
jonahgao
jonahgao commented Jun 26, 2024
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datafusion/sqllogictest/test_files/scalar.slt
@@ -493,41 +493,6 @@ select gcd(a, b), gcd(c, d), gcd(e, f) from signed_integers;
2 1 1
NULL NULL NULL

## lcm
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The tests for lcm existed in two slts and have now been moved to math.slt.

alamb
alamb approved these changes Jun 26, 2024
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Thank you @jonahgao -- the code looks good to me as do the tests. Nice work

datafusion/functions/src/math/lcm.rs
let a = x.unsigned_abs();
let b = y.unsigned_abs();
let gcd = unsigned_gcd(a, b);
// gcd is not zero since both a and b are not zero, so the division is safe.
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👍

@jonahgao
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Thanks @alamb for the review. Merged it since future PRs might conflict on math.slt.

@jonahgao jonahgao merged commit 2d1e850 into apache:main Jun 27, 2024
23 checks passed
@jonahgao jonahgao deleted the fix_lcm branch June 27, 2024 03:15
findepi pushed a commit to findepi/datafusion that referenced this pull request Jul 16, 2024
@jonahgao @findepi
fix: LCM panicked due to overflow (apache#11131)
56381bf 
* fix: LCM panicked due to overflow

* add test

* fix comment
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@alamb alamb alamb approved these changes

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LCM panicked due to overflow
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@jonahgao @alamb