How do I avoid adding a trailing space to a completion item?

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Example Code

my-cli some/remote
# Hit tab
my-cli some/remote
[an-item]    another-item
# Hit enter
my-cli some/remote/an-item
# an-item should be appended with no trailing space

Description

I am specifying a remote path of sorts. It is almost to be treated as a pathlib.Path. I have a completion function defined to return parts of the path one by one and between slashes I don't want a space when I select a completion item by typing on it.

A space is appended anyway.

Operating System

macOS

Operating System Details

No response

Typer Version

0.20.0

Python Version

3.14

Additional Context

No response

[ideacatlab]

There's no per-item "no space" flag in Typer's autocompletion — the trailing space is added by the shell completion script, not by your callback. Typer delegates completion to Click, and for zsh the generated script ends each candidate with compadd -U -V unsorted -a completions, which uses zsh's default suffix (a space). You can confirm it in the generated script. The fix is to override that completion class to pass compadd -S '' (empty suffix = no space).

Click exposes add_completion_class for exactly this, and Typer rides on Click's machinery, so register the override before your app runs:

import click.shell_completion as sc

class NoSpaceZsh(sc.ZshComplete):
    source_template = sc.ZshComplete.source_template.replace(
        "compadd -U -V unsorted -a completions",
        "compadd -S '' -U -V unsorted -a completions",
    )

sc.add_completion_class(NoSpaceZsh, name="zsh")   # replaces the built-in zsh class

import typer
app = typer.Typer()
# ... your commands/autocompletion as before

I verified on Typer 0.27 / Click 8.5 that the rendered zsh completion script then contains compadd -S '' … instead of the default, which is what removes the trailing space — so after selecting an-item you can immediately type / and continue the path, exactly like native path completion.

You'll need to re-install completion after this (your-cli --install-completion, or re-source the generated script) so the new template is picked up.

Two things to know:

• It's per-command, not per-item. -S '' suppresses the suffix space for all completions of that CLI, which is what you want for a path-like argument, but if the same command also has normal word completions elsewhere they'll lose the space too. If that matters, scope the no-space CLI to just the path command, or add a trailing / yourself in the callback for directory-like entries so the UX still reads as "more to come."
• Other shells: the same idea applies but the hook differs. Bash's completion script uses COMPREPLY + compopt, so you'd inject compopt -o nospace (it already uses compopt -o dirnames/-o default); fish uses its own completion with no trailing space by default, so it's mainly bash/zsh that need this.

The zsh override above is the clean, tested one for your macOS setup.