--only-matching only prints first match of matched line N times

[s3rb31]

Take this file as test data. If I do the following with good old grep:

grep -Po "\/get\/v\/\d*" fgi.txt

I get the following result:

/get/v/19670
/get/v/19637
/get/v/19632
/get/v/19600
/get/v/19598
/get/v/19574
/get/v/19523
/get/v/19521
/get/v/19463
/get/v/19457
/get/v/19433
/get/v/19425
/get/v/19392
/get/v/19390
/get/v/19363
/get/v/19358
/get/v/19337
/get/v/19317
/get/v/19295
/get/v/19278
/get/v/19243
/get/v/19241
/get/v/19208
/get/v/19186
/get/v/19128
/get/v/19126

But if I try to achive the same result with rg:

rg -o "/get/v/\d*" fgi.txt -N

/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670
/get/v/19670

I think that behaviour ist really odd and cannot be intended. If I am not mistaken this also violates the documentation (manpage):

-o, --only-matching
    Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line.

But it does not print all the parts. It just prints the first match N times, where N is actually the correct number of matched parts.

I hope this can get fixed. I may create a PR myself if it is not too complicated and someone can lead me the right direction.

Greetings

[bmalehorn]

Here's a much simpler example:

$ cat example.txt
1 2 3

$ grep -Po "[0-9]+" example.txt
1
2
3

$ rg -o "[0-9]+" example.txt -N
1
1
1

@s3rb31 if you want to take a stab it, I believe the bug is here: https://github.com/BurntSushi/ripgrep/blob/master/src/printer.rs#L311 Instead of running the regex again, it should use the original match data to get the start & end.

[kpp]

The column is ok, while data is not:

~/ripgrep$ cat tests/digits.txt 
1 2 3
~/ripgrep$ cargo run -- "\d" tests/digits.txt -o -n --column
    Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
     Running `target/debug/rg '\d' tests/digits.txt -o -n --column`
1:1:1
1:3:1
1:5:1

[kpp]

Sorry for the bug 😭

[s3rb31]

Oh, this was really quick. Thanks for the fix!

I compiled it and it performs well and solid until now. Will report back if I encounter more bugs.

Thanks again!