Improve fish completion script generation #738

rgoldberg · 2025-02-16T07:00:21Z

Improve fish completion script generation.

There are many issues with script generation. Some of them are documented in #679 & its comments.

This issue is for a first batch of fish completion script fixes.

Each commit should note the fix(es) that it contains.

Will rebase if main is updated (especially if #735 is merged).

Resolve #737

Checklist

I've added at least one test that validates that my change is working, if appropriate
I've followed the code style of the rest of the project
I've read the Contribution Guidelines
I've updated the documentation if necessary

rgoldberg · 2025-02-16T19:16:09Z

@natecook1000 Rebased on the new main.

natecook1000

The Swift code looks great, but I'm seeing a few issues in the generated script. It looks like there are two syntax errors in the completion script for math, which I've annotated, and then at execution time I see unexpected output in a couple of situations:

When trying to get completions for either of the arguments, I see this output when I press Tab after quantiles (I had to rename the executable to math2 to work around Fish's built-in math support):

~ $ math2 stats quantiles Error: The value '+' is invalid for '<values>'
Help:  <values>  A group of integers to operate on.
Usage: math add [--hex-output] [<values> ...]
  See 'math add --help' for more information.
test: Missing argument at index 3
-eq 2
      ^
in command substitution
Error: The value '+' is invalid for '<values>'
Help:  <values>  A group of integers to operate on.
Usage: math add [--hex-output] [<values> ...]
  See 'math add --help' for more information.
test: Missing argument at index 3
-eq 1
      ^
in command substitution

The --custom completion worked, but printed an extra error message first:

~ $ math2 stats quantiles --file Desktop/add-preamble.txt --directory Desktop/Desktop/ --shell Abaris --custom Error: The value '+' is invalid for '<values>'
Help:  <values>  A group of integers to operate on.
Usage: math add [--hex-output] [<values> ...]
~ $ math2 stats quantiles --file Desktop/add-preamble.txt --directory Desktop/Desktop/ --shell Abaris --custom hel
hello  helicopter  heliotrope

natecook1000 · 2025-02-16T19:22:43Z

Tests/ArgumentParserExampleTests/Snapshots/testMathFishCompletionScript().fish

+            switch $POSITIONALS[1]
+            case 'average'
+                _swift_math_commands_and_positionals_helper '' 'kind= version h/help'
+            case 'stdev'
+                _swift_math_commands_and_positionals_helper '' 'version h/help'
+            case 'quantiles'
+                _swift_math_commands_and_positionals_helper '' 'file= directory= shell= custom= version h/help'


Fish error: missing an end for this switch statement.

Pushed a fix for this.

natecook1000 · 2025-02-16T19:24:10Z

Tests/ArgumentParserExampleTests/Snapshots/testMathFishCompletionScript().fish

+    set tokens (_swift_math_tokens -p)
+    if test -z (_swift_math_tokens -t)
+        set index (count (_swift_math_tokens -pc))
+        set tokens $tokens[..$index] \'\' $tokens[$(math $index + 1)..]


Fish error: can't use the $(...) syntax, have to just use (...) instead:

Suggested change

set tokens $tokens[..$index] \'\' $tokens[$(math $index + 1)..]

set tokens $tokens[..$index] \'\' $tokens[(math $index + 1)..]

A bit ago, while testing fish with 4.0b1, I got an error using (…) instead of using $(…). I switched to $(…), which fixed the error.

After fixing the missing end problem (but not having worked on non-mutually-exclusive positionals & subcommands nor having made any other changes), I just verified that the both syntaxes offer helicopter, heliotrope & hello as completions for the following command line when completing with the cursor at ^ (which is not a literal caret, but just a marker to indicate the cursor location) on my macOS 12.7.6 Mac mini (2014) using fish 3.7.1 (which is the current stable version of fish) installed via Homebrew core:

command math stats quantiles --custom ^

What command & where in it did you try to complete? What version of fish? Etc.

I set this up by copying testMathFishCompletionScript().fish from the repo to ~/.config/fish/completions/math.fish, started fish 3.7.1 without any arguments, then ran:

fish_add_path /Users/username/Code/swift-argument-parser/.build/debug/

then completed at the end of the aforementioned command math stats quantiles --custom command line.

The math command had previously been built via swift test from zsh 5.9 installed via Homebrew core on the same Mac mini.

rgoldberg · 2025-02-16T20:42:53Z

@natecook1000 Sorry, I forgot to make a change to the fish completion script (it currently incorrectly assumes that positionals & subcommands are mutually exclusive).

I'll work on the change, then push a new version of the PR.

I'll test it more thoroughly.

Might be later tonight or tomorrow.

Am sick (as of yesterday morning) & was too hastily trying to finish getting my changes merged that my look over was too lax.

rgoldberg · 2025-02-17T10:33:25Z

@natecook1000 Some improvements that I've tried from fish 4.0b1 have some problems. I had messaged the fish people a bit about them, but it all fell by the wayside.

It seems like they might release 4.0 in a few weeks without any more prereleases after 4.0b1, so whenever I have their attention, I will concentrate on trying to get them to implement some some fixes.

I don't know Rust, nor do I know the fish codebase, so I probably cannot contribute code effectively to fish itself.

In the meantime, I will fix the issues in the fish PR as much as I can, but the eventual code might need to be different than the current paradigm to overcome fish shortcomings (e.g., I might need to tokenize the whole command line myself instead of using their standard tokenization), if fish 4.0 doesn't include certain improvements.