> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/tuist/tuist/llms.txt
> Use this file to discover all available pages before exploring further.

# tuist hash

> Debug hashing logic for binary caching and selective testing

## Overview

The `tuist hash` command provides utilities to debug the hashing logic used by features like binary caching and selective testing. It helps you understand how Tuist calculates hashes for your targets and dependencies.

## Usage

```bash theme={null}
tuist hash [subcommand] [options]
```

## Subcommands

### `tuist hash cache`

Returns the hashes that will be used to persist binaries of the graph in its current state to the cache.

```bash theme={null}
tuist hash cache [options]
```

### `tuist hash selective-testing`

Returns the hashes that will be used to persist targets' test results to select tests in future test runs.

```bash theme={null}
tuist hash selective-testing [options]
```

## Options (for `hash cache`)

<ParamField path="--path" type="string" default=".">
  The path to the directory that contains the project whose targets will be cached.
</ParamField>

<ParamField path="-p" type="string">
  Short form of `--path`.
</ParamField>

<ParamField path="--configuration" type="string">
  The project configuration the cache binaries will be bound to (e.g., Debug, Release).
</ParamField>

<ParamField path="-c" type="string">
  Short form of `--configuration`.
</ParamField>

## Options (for `hash selective-testing`)

<ParamField path="--path" type="string" default=".">
  The path to the directory that contains the project whose tests will run selectively.
</ParamField>

<ParamField path="-p" type="string">
  Short form of `--path`.
</ParamField>

## Examples

### Get cache hashes for current state

```bash theme={null}
tuist hash cache
```

Displays the hashes for all targets in the project that will be used for binary caching.

### Get cache hashes for specific configuration

```bash theme={null}
tuist hash cache --configuration Release
```

Shows the hashes that will be used when caching binaries with the Release configuration.

### Get selective testing hashes

```bash theme={null}
tuist hash selective-testing
```

Displays the hashes used to track test results for selective test execution.

### Get hashes for specific project path

```bash theme={null}
tuist hash cache --path path/to/project
```

Calculates hashes for targets in the specified project directory.

## Understanding hashing

Tuist's hashing system is crucial for both binary caching and selective testing:

### Cache hashing

The cache hash for a target is calculated based on:

1. Source files and their contents
2. Build settings and configuration
3. Dependencies and their hashes (cascading)
4. Resources and other target inputs

When any of these change, the hash changes, indicating that the cached binary is no longer valid.

### Selective testing hashing

The selective testing hash is used to determine:

1. Which tests need to run based on code changes
2. Which test results can be reused from previous runs
3. Dependencies between test targets and source code

## Debugging cache misses

Use `tuist hash cache` to debug why binaries aren't being retrieved from cache:

1. Run the command before and after changes
2. Compare the hashes to identify which targets changed
3. Investigate why unchanged targets show different hashes

Common causes of unexpected hash changes:

* Generated files with timestamps
* Environment-dependent build settings
* Absolute paths in build settings
* Dependency version updates

## Best practices

<CardGroup cols={2}>
  <Card title="Verify hashing" icon="fingerprint">
    Use `tuist hash cache` to verify that your cache configuration is working as expected.
  </Card>

  <Card title="Debug cache misses" icon="magnifying-glass">
    Compare hashes before and after changes to understand cache invalidation.
  </Card>

  <Card title="Test selectivity" icon="filter">
    Use `tuist hash selective-testing` to debug selective test execution.
  </Card>

  <Card title="Configuration consistency" icon="sliders">
    Ensure you use the same configuration when generating and hashing.
  </Card>
</CardGroup>

## Related

* [Cache command](/cli/cache)
* [Test command](/cli/test)
* [Generate command](/cli/generate)