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Fix Printf for typemin(<:Base.BitSigned) #42341

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merged 8 commits into from
Sep 27, 2021
Merged

Fix Printf for typemin(<:Base.BitSigned) #42341

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9f770e4
Fix Printf for typemin(<:Signed)
petvana Sep 22, 2021
a2acb03
Merge branch 'JuliaLang:master' into fix-printf
petvana Sep 22, 2021
871dd87
Enforce the unsigned type
petvana Sep 22, 2021
d104f5e
Simplify the code thanks to defined overflow behavior in Julia
petvana Sep 22, 2021
0262f4c
Update type check because BigInt (and maybe other user-defined types)…
petvana Sep 22, 2021
a8798a7
Use Base.BitSigned
petvana Sep 22, 2021
0b6b06c
Replace typeof(x) <: T by x isa T
petvana Sep 23, 2021
c128d04
Simplify to one-liner code using abs()
petvana Sep 23, 2021
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8 changes: 7 additions & 1 deletion stdlib/Printf/src/Printf.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -292,7 +292,13 @@ fmt(buf, pos, arg::AbstractFloat, spec::Spec{T}) where {T <: Ints} =
bs = base(T)
arg2 = toint(arg)
n = i = ndigits(arg2, base=bs, pad=1)
x, neg = arg2 < 0 ? (-arg2, true) : (arg2, false)
one = oneunit(arg2)
neg = arg2 < 0
if typeof(arg2) <: Signed && !(typeof(arg2) <: BigInt)
x = neg ? unsigned(-(arg2+one))+unsigned(one) : unsigned(arg2)
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What about x = unsigned(abs(arg2))? That fixes the problematic case and avoids any conversion problems, since the typemin is handled by unsigned and all other negative values are handled by abs (since they're guaranteed to still fit into the original type).

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Thanks for the comment, I have updated to x = unsigned(neg ? -arg2 : arg2) to be closer to the original code with the same meaning.

else
x = neg ? -arg2 : arg2
end
arglen = n + (neg || (plus | space)) +
(T == Val{'o'} && hash ? 1 : 0) +
(T == Val{'x'} && hash ? 2 : 0) + (T == Val{'X'} && hash ? 2 : 0)
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11 changes: 11 additions & 0 deletions stdlib/Printf/test/runtests.jl
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Expand Up @@ -762,6 +762,17 @@ end
@test Printf.@sprintf("%20.0X", UInt(3989525555)) == " EDCB5433"
@test Printf.@sprintf("%20.X", UInt(0)) == " 0"

# issue #41971
@test Printf.@sprintf("%4d", typemin(Int8)) == "-128"
@test Printf.@sprintf("%4d", typemax(Int8)) == " 127"
@test Printf.@sprintf("%6d", typemin(Int16)) == "-32768"
@test Printf.@sprintf("%6d", typemax(Int16)) == " 32767"
@test Printf.@sprintf("%11d", typemin(Int32)) == "-2147483648"
@test Printf.@sprintf("%11d", typemax(Int32)) == " 2147483647"
@test Printf.@sprintf("%20d", typemin(Int64)) == "-9223372036854775808"
@test Printf.@sprintf("%20d", typemax(Int64)) == " 9223372036854775807"
@test Printf.@sprintf("%40d", typemin(Int128)) == "-170141183460469231731687303715884105728"
@test Printf.@sprintf("%40d", typemax(Int128)) == " 170141183460469231731687303715884105727"
end

@testset "%n" begin
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