# XO1302: module version cannot be fetched

A module path is its location: `github.com/acme/billing` is fetched with git from https://github.com/acme/billing.git (XO_GIT_BASE=\<dir or URL> or XO_GIT_REWRITE=\<prefix>=\<url>,... point it elsewhere, for mirrors and tests), and version v1.4.0 is the tree of the tag `v1.4.0`, extracted with `git archive` (no code runs). A module in a subdirectory of its repository (`github.com/acme/tools/cli` in `cli/`) is that directory's tree at the tag `cli/v1.4.0`. This failed: the repository cannot be reached or cloned, it has no such tag, the tag has no xo.mod in the module's directory, or that xo.mod declares a different module path. The message carries git's reason. With XO_PROXY listing module proxies, the message carries each source's answer: a proxy that does not have the version (404) passes on to the next source after a comma, any error does after a pipe, and `off` forbids fetching. A zip with paths outside the module, or a tree that contradicts the proxy's own .lock answer, also fails here. See core 4.2 and decisions 0086 and 0126.

## Example

```xo
// xo.mod
module example.com/api
require github.com/acme/billing v1.9.9   // no such tag
```

## Fix

```xo
// pick an existing tag (xo get github.com/acme/billing takes the latest)
module example.com/api
require github.com/acme/billing v1.4.0
```

Run `xo explain XO1302` for this text in a terminal, or see
[section 10.6 of the specification](../../spec/core/#106-diagnostic-codes).