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fix: number.floor rounds toward -infinity (not toward zero) #5048

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fix: number.floor rounds toward -infinity (not toward zero) #5048

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28 changes: 24 additions & 4 deletions eo-runtime/src/main/eo/number.eo
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Original file line number Diff line number Diff line change
Expand Up @@ -112,8 +112,16 @@
# The object rounds down the original `number` to the nearest
# whole `number` that is less than or equal to it
# and returns the result as `org.eolang.number`.
# For non-finite inputs (NaN, ±infinity) the input is returned unchanged.
[] > floor
as-i64.as-number > @
if. > @
is-finite.not
$
if.
trunc.gt $
trunc.minus 1
trunc
as-i64.as-number > trunc
Comment on lines +115 to +124
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@coderabbitai coderabbitai Bot Apr 24, 2026

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⚠️ Potential issue | 🟠 Major

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# 1) Find any use of a bare `$` as a value inside method bodies in .eo files.
rg -nP --type-add 'eo:*.eo' --type=eo -C3 '^\s*\$\s*$|[^\w$]\$(\s|$)' eo-runtime/src/main/eo

# 2) Find uses of `^` (parent reference) to see the established idiom for
#    "refer to the enclosing object from inside a method body".
rg -nP --type-add 'eo:*.eo' --type=eo -C3 '(^|[^\w])\^(\.|\s|$)' eo-runtime/src/main/eo | head -n 200

# 3) Surface the exact test objects that rely on floor for non-finite inputs,
#    to confirm they actually invoke `.floor` (and are not shadowed by `.@`):
rg -nP --type-add 'eo:*.eo' --type=eo -C2 'floor' eo-runtime/src/main/eo/positive-infinity.eo eo-runtime/src/main/eo/negative-infinity.eo

Repository: objectionary/eo

Length of output: 23296

Verify that $ refers to the enclosing number, not to the floor method itself.

In EO, ^ is the established pattern for referencing the enclosing parent object in method bodies. The implementation at lines 119 and 121 uses bare $, which is not found elsewhere in the codebase in this style.

Two locations are affected:

  • Line 119 ($ as the non-finite branch result): if $ dataizes through floor.@, this creates a cycle.
  • Line 121 (trunc.gt $): comparing trunc against $ dataizes the floor method rather than the input number.

Tests for negative-infinity.floor and positive-infinity.floor exist (negative-infinity.eo:502–503, positive-infinity.eo:515–516), but they must be confirmed to exercise the floor method correctly. If $ is incorrect, replace it with ^ (or an explicit binding like as-bytes.as-number > original). Verify that nan.floor, positive-infinity.floor, and negative-infinity.floor evaluate correctly on both JVM and eo2js runtimes before merging.

🤖 Prompt for AI Agents 
Verify each finding against the current code and only fix it if needed.

In `@eo-runtime/src/main/eo/number.eo` around lines 115 - 124, The floor method is
incorrectly using bare `$` which refers to the method object dataization and can
create cycles; change those `$` references inside the floor body to reference
the enclosing number (use `^` or bind the input to a name like `original` before
transformations) so the non-finite branch returns the original numeric value and
the comparison `trunc.gt` compares against that original number; update
references in the floor implementation (symbols: floor, trunc, is-finite,
as-i64.as-number) and re-run nan.floor, positive-infinity.floor and
negative-infinity.floor tests on both JVM and eo2js to confirm correct behavior.


# Tests that less-than comparison returns true when first number is smaller.
[] +> tests-int-less-true
Expand Down Expand Up @@ -351,26 +359,38 @@
eq. > @
floor.
13.div -5
-2
-3

# Tests that floor of a positive fractional number truncates toward zero.
[] +> tests-floor-positive-fraction
eq. > @
3.7.floor
3

# Tests that floor of a negative fractional number truncates toward zero.
# Tests that floor of a negative fractional number rounds toward -infinity.
[] +> tests-floor-negative-fraction
eq. > @
-3.7.floor
-3
-4

# Tests that floor of a small negative fraction rounds toward -infinity, not zero.
[] +> tests-floor-small-negative-fraction
eq. > @
-0.1.floor
-1

# Tests that floor of a whole number returns the same number.
[] +> tests-floor-of-integer
eq. > @
42.floor
42

# Tests that floor of a negative whole number returns the same number.
[] +> tests-floor-of-negative-integer
eq. > @
-42.floor
-42

# Tests that division result can be less than one.
[] +> tests-div-less-than-one
lt. > @
Expand Down
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