Don't use UV_LOCKED to enable --check flag (#16521)

Env var UV_LOCKED should only be used to enable `--locked` for the `uv
lock` command. Previously `--check` was also enabled by specifying
UV_LOCKED.

crates/uv-cli/src/lib.rs

@@ -3733,7 +3733,7 @@ pub struct LockArgs {
     /// missing or needs to be updated, uv will exit with an error.
     ///
     /// Equivalent to `--locked`.
-    #[arg(long, env = EnvVars::UV_LOCKED, value_parser = clap::builder::BoolishValueParser::new(), conflicts_with_all = ["check_exists", "upgrade", "locked"])]
+    #[arg(long, value_parser = clap::builder::BoolishValueParser::new(), conflicts_with_all = ["check_exists", "upgrade", "locked"])]
     pub check: bool,
 
     /// Check if the lockfile is up-to-date.

docs/reference/cli.md

@@ -1637,7 +1637,7 @@ uv lock [OPTIONS]
 <p>May also be set with the <code>UV_CACHE_DIR</code> environment variable.</p></dd><dt id="uv-lock--check"><a href="#uv-lock--check"><code>--check</code></a></dt><dd><p>Check if the lockfile is up-to-date.</p>
 <p>Asserts that the <code>uv.lock</code> would remain unchanged after a resolution. If the lockfile is missing or needs to be updated, uv will exit with an error.</p>
 <p>Equivalent to <code>--locked</code>.</p>
-<p>May also be set with the <code>UV_LOCKED</code> environment variable.</p></dd><dt id="uv-lock--check-exists"><a href="#uv-lock--check-exists"><code>--check-exists</code></a>, <code>--frozen</code></dt><dd><p>Assert that a <code>uv.lock</code> exists without checking if it is up-to-date.</p>
+</dd><dt id="uv-lock--check-exists"><a href="#uv-lock--check-exists"><code>--check-exists</code></a>, <code>--frozen</code></dt><dd><p>Assert that a <code>uv.lock</code> exists without checking if it is up-to-date.</p>
 <p>Equivalent to <code>--frozen</code>.</p>
 <p>May also be set with the <code>UV_FROZEN</code> environment variable.</p></dd><dt id="uv-lock--color"><a href="#uv-lock--color"><code>--color</code></a> <i>color-choice</i></dt><dd><p>Control the use of color in output.</p>
 <p>By default, uv will automatically detect support for colors when writing to a terminal.</p>