from ssv is unable to detect empty columns

[waldyrious]

Describe the bug

Using the example output from the docker ps documentation:

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
673394ef1d4c        busybox             "top"               47 seconds ago      Up 45 seconds                           nostalgic_shockley
d85756f57265        busybox             "top"               52 seconds ago      Up 51 seconds                           high_albattani

Here's how from ssv parses it:

> cat ~/docker-ps.txt | from ssv
───┬──────────────┬─────────┬─────────┬────────────────┬───────────────┬────────────────────
 # │ CONTAINER ID │  IMAGE  │ COMMAND │    CREATED     │    STATUS     │       PORTS        
───┼──────────────┼─────────┼─────────┼────────────────┼───────────────┼────────────────────
 0 │ 673394ef1d4c │ busybox │ "top"   │ 47 seconds ago │ Up 45 seconds │ nostalgic_shockley 
 1 │ d85756f57265 │ busybox │ "top"   │ 52 seconds ago │ Up 51 seconds │ high_albattani     
───┴──────────────┴─────────┴─────────┴────────────────┴───────────────┴────────────────────

Note how the contents of the NAMES column were pulled into the PORTS column, which should be empty, and the NAMES column header doesn't even appear.

How to reproduce

1. Create a ~/docker-ps.txt file with the contents indicated above
2. Run ~/docker-ps.txt | from ssv

Expected behavior

The correct output should be:

> cat ~/docker-ps.txt | from ssv
───┬──────────────┬─────────┬─────────┬────────────────┬───────────────┬───────┬────────────────────
 # │ CONTAINER ID │  IMAGE  │ COMMAND │    CREATED     │    STATUS     │ PORTS │       NAMES        
───┼──────────────┼─────────┼─────────┼────────────────┼───────────────┼───────┼────────────────────
 0 │ 673394ef1d4c │ busybox │ "top"   │ 47 seconds ago │ Up 45 seconds │       │ nostalgic_shockley 
 1 │ d85756f57265 │ busybox │ "top"   │ 52 seconds ago │ Up 51 seconds │       │ high_albattani     
───┴──────────────┴─────────┴─────────┴────────────────┴───────────────┴───────┴────────────────────

Screenshots

No response

Configuration

key	value
version	0.40.0
build_os	linux-x86_64
rust_version	rustc 1.56.1
cargo_version	cargo 1.56.0
pkg_version	0.40.0
build_time	1980-01-01 00:00:00 +00:00
build_rust_channel	release
features	clipboard-cli, ctrlc, dataframe, default, rustyline, term, trash, uuid, which, zip
installed_plugins	binaryview, chart bar, chart line, fetch, from bson, from sqlite, inc, match, post, ps, query json, s3, selector, start, sys, textview, to bson, to sqlite, tree, xpath

Additional context

If it helps, detect columns is able to identify the empty column:

> cat ~/docker-ps.txt | detect columns
───┬──────────────┬──────────────┬─────────┬─────────┬─────────┬─────────┬───────┬────────────────────
 # │  CONTAINER   │      ID      │  IMAGE  │ COMMAND │ CREATED │ STATUS  │ PORTS │       NAMES        
───┼──────────────┼──────────────┼─────────┼─────────┼─────────┼─────────┼───────┼────────────────────
 0 │ 673394ef1d4c │ 673394ef1d4c │ busybox │ "top"   │ seconds │ seconds │       │ nostalgic_shockley 
 1 │ d85756f57265 │ d85756f57265 │ busybox │ "top"   │ seconds │ seconds │       │ high_albattani     
───┴──────────────┴──────────────┴─────────┴─────────┴─────────┴─────────┴───────┴────────────────────

(There are other bugs in this output, but I'll report those separately. EDIT: Reported them as #4183.)

[sophiajt]

@waldyrious - out of curiosity, does the detect columns command do better here?

[waldyrious]

@jntrnr yes, but it has its own issues — see the "Additional context" section above :)

[fdncred]

This works | from ssv --aligned-columns in 0.59.1. Closing.

╭───┬──────────────┬─────────┬─────────┬────────────────┬───────────────┬───────┬────────────────────╮
│ # │ CONTAINER ID │  IMAGE  │ COMMAND │    CREATED     │    STATUS     │ PORTS │       NAMES        │
├───┼──────────────┼─────────┼─────────┼────────────────┼───────────────┼───────┼────────────────────┤
│ 0 │ 673394ef1d4c │ busybox │ "top"   │ 47 seconds ago │ Up 45 seconds │       │ nostalgic_shockley │
│ 1 │ d85756f57265 │ busybox │ "top"   │ 52 seconds ago │ Up 51 seconds │       │ high_albattani     │
├───┼──────────────┼─────────┼─────────┼────────────────┼───────────────┼───────┼────────────────────┤
│ # │ CONTAINER ID │  IMAGE  │ COMMAND │    CREATED     │    STATUS     │ PORTS │       NAMES        │
╰───┴──────────────┴─────────┴─────────┴────────────────┴───────────────┴───────┴────────────────────╯

[waldyrious]

Looks like this was a duplicate of #1350 after all. But as @kvrhdn commented there, it's not clear why --aligned-columns isn't the default behavior. I can see that it actually used to be the default, and the behavior was changed in #912 to fix #910, but honestly, when data is space-separated, isn't it more likely that it's column-aligned than not? I'd argue that the flag should be reversed, aligned columns should be the default, and opting out from that could be implemented with a flag like --unaligned-columns or something along those lines. WDYT @jntrnr?

[Caedan]

Looks like this was a duplicate of #1350 after all. But as @kvrhdn commented there, it's not clear why --aligned-columns isn't the default behavior. I can see that it actually used to be the default, and the behavior was changed in #912 to fix #910, but honestly, when data is space-separated, isn't it more likely that it's column-aligned than not? I'd argue that the flag should be reversed, aligned columns should be the default, and opting out from that could be implemented with a flag like --unaligned-columns or something along those lines. WDYT @jntrnr?

@waldyrious Good shout! Has there been a discussion on discord perhaps? I would be open to take this work on in case it's settled.

[waldyrious]

Has there been a discussion on discord perhaps?

Not that I'm aware of (I'm not on the Discord server).