make-pot fails without network: remote_get() doesn't catch the exception http_request() throws, so the bundled schemas are never used #518

wp i18n make-pot fetches block-i18n.json and theme-i18n.json from wordpress-develop's trunk, and is meant to fall back to the copies it bundles (JsonSchemaExtractor::THEME_JSON_FALLBACK and BLOCK_JSON_FALLBACK) when the fetch fails. remote_get() passes halt_on_error => false, and its docblock says it "Returns an empty string in case of error".

But on a transport error, WP_CLI\Utils\http_request() with halt_on_error false doesn't return a failed response. It throws a RuntimeException (wp-cli/wp-cli php/utils.php, both throw new RuntimeException( $error_msg, 0, $exception ) paths). remote_get() doesn't catch it, so make-pot aborts and the fallback is never used.

Steps to reproduce

1. Use a plugin or theme with a block.json (or a theme.json).
2. Run WP-CLI with the i18n command and no network, for example in a container started with docker run --network none. PHP without a CA bundle (php-wasm) hits the same path.
3. Run wp i18n make-pot . languages/x.pot.

Expected

A debug message ("Failed to download from URL …"), extraction with the bundled schema, and the POT written.

Actual

make-pot stops with Failed to get url 'https://develop.svn.wordpress.org/trunk/src/wp-includes/block-i18n.json': … and writes nothing.

Seen with 2.7.0, and the code is the same on main.

Suggested fix

Catch RuntimeException around the http_request() call in remote_get() and return '', which already selects the fallback. A Behat scenario could run make-pot with the proxy set to an unreachable address.

For context: we run make-pot under php-wasm and in containers without network. Until this is fixed, we seed the extractor's schema cache with the bundled copies before make-pot runs (a --require file hooked on before_invoke:i18n make-pot).