# Description
I introduced a regression in #13272 that resulted in `detect columns
--guess` to panic whenever it had to handle empty, whitespace-only, or
non-whitespace-only lines that go all the way to the last column (and as
such, cannot be considered to be lines that only have entries for the
first colum). I fix this by detecting these cases and skipping them,
since these are usually decoration lines. An example is the second line
output by `winget list`:
What we don't want to skip, however, is lines that contain no
whitespace, and fit into the detected first column, since these lines
represent cases where data is only available for the first column, and
are not just decoration lines. For example (made up example, there are
no such entries in `winget lits`'s output), in this output we would not
want to skip the `Docker Desktop` line :
```
Name Id Version Available Source
-------------------------------------------------------------------------------------------------------------------------------------
AMD Software ARPMachineX64AMD Catalyst Install Manager 24.4.1
AMD Ryzen Master ARPMachineX64AMD Ryzen Master 2.13.0.2908
Docker Desktop
Mozilla Firefox (x64 en-US) Mozilla.Firefox 127.0.2 winget
```
NOTE: `winget list | detect columns --guess` does not panic, but sadly
still does not work as expected. I believe this is not a nushell issue
anymore, but a `winget` one. When being piped, `winget` seems to add
extra whitespace and random `\r` symbols at the beginning of the text.
This messes with the column detection, of course.
# User-Facing Changes
`detect columns --guess` should not panic when receiving output from
`winget list` at all anymore.
A breaking change is the skipping of decoration lines, especially since
scripts probably were doing something like
`winget list | lines | reject 1 | str join "\n" | detect columns
--guess`. This will now cause them to reject a line with valid data.
# Tests + Formatting
Added tests that exercise these edge cases, as well as a single-column
test to make sure that trivial cases keep working.
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# Description
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This PR fixes#13269. The splitting code in `guess_width.rs` was
creating slices from char indices, instead of byte indices. This works
perfectly fine for 1-byte code points, but panics or returns wrong
results as soon as multibyte codepoints appear in the input. I
originally discovered this by piping `winget list` into `detect columns
--guess`, since winget sometimes uses the unicode ellipsis symbol (`…`)
which is 3 bytes long when encoded in utf-8.
# User-Facing Changes
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helps us keep track of breaking changes. -->
`detect columns --guess` should not crash due to multibyte unicode input
anymore
before:
after:
# Tests + Formatting
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- Added tests to `guess_width.rs` for testing handling of multibyte as
well as combining diacritical marks
# After Submitting
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# Description
@fdncred found another histogram based algorithm to detect columns, and
rewrite it in rust: https://github.com/fdncred/guess-width
I have tested it manually, and it works good with `df`, `docker ps`,
`^ps`. This pr is going to use the algorithm in `detect columns`
Fix: #4183
The pitfall of new algorithm:
1. it may not works well if there isn't too much rows of input
2. it may not works well if the length of value is less than the header
to value, e.g:
```
c1 c2 c3 c4 c5
a b c d e
g h i j k
g a a q d
a v c q q | detect columns
```
In this case, users might need to use ~~`--old`~~ `--legacy` to make it
works well.
# User-Facing Changes
User might need to add ~~`--old`~~ `--legacy` to scripts if they find
`detect columns` in their scripts broken.
# Tests + Formatting
Done
# After Submitting
NaN
