---
slug: proto-v0.26
title: proto v0.26 - New native shim implementation
authors: [milesj]
tags: [proto, shim]
# image: ./img/proto/v0.26.png
---

After many release candidates, and a ton of testing, proto v0.26 is finally here!

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## Rethinking shims

proto at its core is a version manager, which means like most version managers, it relies on a
concept known as shims. Shims are lightweight executable scripts that act like a proxy to the
underlying binary, and are useful for proto to intercept executions and inject custom functionality,
like our dynamic version detection.

On Unix machines, we relied on Bash scripts for shims, which worked rather well. However, on
Windows, we relied on PowerShell scripts (`.ps1`), batch/cmd scripts (`.cmd`), and Bash scripts, all
with differing levels of functionality, and each serving a separate purpose. Windows support _did
not_ work well.

To avoid current and future compatibility issues, we needed a truly native solution, and that's
exactly what we did. In this release, we wrote our own Rust based executable, that will replace all
of the custom shim scripts. This new executable is named `proto-shim` (`proto-shim.exe` on Windows)
and is published alongside the `proto` binary.

This new executable solves all of the following problems (hopefully):

- Locatable on `PATH` (is an `.exe` for Windows)
- Can pipe/redirect data
- Handles stdin prompts/interactivity
- Supports ctrl+c interruptions
- Passes parent signals to child processes (uses `execvp` on Unix)
- Attempts to kill child processes on parent exit
- Bubbles exit codes
- Native performance
- Doesn't require special privileges (no symlinks)

## Upgrade troubleshooting

Because this release adds a new executable (`proto-shim`), you'll most likely run into issues when
upgrading via `proto upgrade`. The root issue is that the upgrade process was only aware of the
single `proto` file, and not the new `proto-shim` file, so it will not copy the shim into the
correct location, and subsequent proto commands will fail.

We could backport this change to v0.25, but it would require all users to upgrade to that patch
version first before upgrading to v0.26. But this still wouldn't solve the issue for users upgrading
from v0.24, or an even earlier version.

The best way to remedy this situation is to simply
[re-install proto as a whole](/docs/proto/install). Once you're on v0.26, this will be a non-issue.

```shell
# Unix
curl -fsSL https://moonrepo.dev/install/proto.sh | bash

# Windows
irm https://moonrepo.dev/install/proto.ps1 | iex
```

## Other changes

View the [official release](https://github.com/moonrepo/proto/releases/tag/v0.26.0) for a full list
of changes.

- Added basic telemetry to track tool install/uninstall metrics.
- Fixed an issue where binaries were being symlinked with broken versions in their file name (most
  commonly for Python).
