Fixes#223. Very simple reproduction
```
cd diffutils
mkdir a
touch a/alef a/alefn a/alef_ a/alefx a/alefr a/fuzz.file
cargo test
```
=> fail
https://www.gnu.org/software/diffutils/manual/html_node/Multiple-Patches.html
states that the "old" file name has precedence over the "new" filename.
I hit this problem because some other (and unfortunately: unknown for
now) test issue left bogus `a/alef*` file(s) behind in my workspace. I
didn't bother cleaning them up because I assumed some test would keep
recreating them and that cost me a lot of time.
This issue seems to have existed since the very first commit.
Interestingly, there as a previous attempt in 2024 to fix this in commit
a3a372ff36 ! So I was apparently not the only affected. BUT that
fix was immediately reverted by commit ba7cb0aef9 in the same
PR. Admittedly, that fix seemed somewhat off-topic in
https://github.com/uutils/diffutils/pull/33. So here it is again.
Create the diff -y utility, this time introducing tests and changes focused
mainly on the construction of the utility and issues related to alignment
and response tabulation. New parameters were introduced such as the size
of the total width of the output in the parameters. A new calculation was
introduced to determine the size of the output columns and the maximum
total column size. The tab and spacing mechanism has the same behavior
as the original diff, with tabs and spaces formatted in the same way.
- Introducing tests for the diff 'main' function
- Introducing fuzzing for side diff utility
- Introducing tests for internal mechanisms
- Modular functions that allow consistent changes across the entire project
The utility should support all the arguments supported by GNU cmp and
perform slightly better.
On a "bad" scenario, ~36M files which are completely different, our
version runs in ~72% of the time of the original on my M1 Max:
> hyperfine --warmup 1 -i --output=pipe \
'cmp -l huge huge.3'
Benchmark 1: cmp -l huge huge.3
Time (mean ± σ): 3.237 s ± 0.014 s [User: 2.891 s, System: 0.341 s]
Range (min … max): 3.221 s … 3.271 s 10 runs
Warning: Ignoring non-zero exit code.
> hyperfine --warmup 1 -i --output=pipe \
'../target/release/diffutils cmp -l huge huge.3'
Benchmark 1: ../target/release/diffutils cmp -l huge huge.3
Time (mean ± σ): 2.392 s ± 0.009 s [User: 1.978 s, System: 0.406 s]
Range (min … max): 2.378 s … 2.406 s 10 runs
Warning: Ignoring non-zero exit code.
Our cmp runs in ~116% of the time when comparing libxul.so to the
chromium-browser binary with -l and -b. In a best case scenario of
comparing 2 files which are the same except for the last byte, our
tool is slightly faster.
Daniel Hofstetter
Marc Herbert
pocopepe
xtqqczze
Gunter Schmidt
renovate[bot]
Sylvestre Ledru
Sami Daniel (Tsoi)
Gustavo Noronha Silva
Olivier Tilloy
hanbings
Michael Howell