uutils / uutils/coreutils

bug(printf): %.a with hex large values lead to output mismatch between gnu and uu

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U - printf
Dominant language
Rust
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Description

Hi, uutils mainteners

we confirmed that when testing printf here is how can be reproduced

relunsec@relunsec:~/software/coreutils/target/debug$ ./printf %.a 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
0x1p+216relunsec@relunsec:~/software/coreutils/target/debug$ 
relunsec@relunsec:~/software/coreutils/target/debug$ gnuprintf %.a 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF
0x8p+213relunsec@relunsec:~/software/coreutils/target/debug$ 

as you can see there was a big difference in the output

Contributor guide

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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by locating the printf implementation and reproduce the reported %.a case with the large hexadecimal value shown in the issue. Compare the output with GNU printf and inspect the relevant floating-point parsing or formatting path. Done means the uutils printf output matches GNU for this case, with regression coverage if the existing tests provide a suitable place.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
cli
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Active
Clarity
Mostly clear
Newbie friendliness
66/100

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