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Padded encoded ULIDs to canonical length #11

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Merged
rkadaj merged 1 commit into from
Jun 4, 2026
Merged

Padded encoded ULIDs to canonical length #11

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5 changes: 1 addition & 4 deletions lib/ulid/generate.rb
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Original file line number Diff line number Diff line change
Expand Up @@ -19,10 +19,7 @@ def encode32
b32 = value.to_s(32)
b32.tr!(B32_RCF4648_FRAGMENT, B32_CROCKFORD_FRAGMENT)
b32.upcase!

return "0#{b32}" if b32.length == 25

b32
b32.rjust(26, "0")
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@martelogan martelogan Jun 4, 2026

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👍 , per discussion on slack, this should be fine as I believe the prior version was just a micro-optimization assuming a single leading zero for 25-char ULIDs generated using the shortest possible representation, but there should be no issue to replace with rjust(26, "0") to handle an arbitrary number of leading zeroes for alternative underlying representations

end

def encode16
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8 changes: 8 additions & 0 deletions spec/ulid_spec.rb
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Expand Up @@ -64,6 +64,10 @@
expect(ulid_string).to be_instance_of(String)
end

it 'generates the minimum ULID at the Unix epoch' do
expect(ULID.min_ulid_at(Time.at(0))).to eq("00000000000000000000000000")
end

it 'generates the lowest lexicographical ULID' do
expect(ulid_string).to match(/0000000000000000$/)
end
Expand Down Expand Up @@ -265,6 +269,10 @@
expect(other.bytes).to eq(first.bytes)
expect(other.time).to eq(first.time)
end

it 'pads the lowest possible encoded value to 26 characters' do
expect(ULID.new(0).ulid).to eq("00000000000000000000000000")
end
end

describe 'compared to other ULIDs' do
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