do not imply pre-release when != operator is used (#7974)

closes #6640

Could you suggest how I should test it?

(already tested locally)

---------

Co-authored-by: konstin <konstin@mailbox.org>
Co-authored-by: Charles Tapley Hoyt <cthoyt@gmail.com>
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>

crates/uv-resolver/src/prerelease.rs

@@ -1,10 +1,11 @@
 use uv_pypi_types::RequirementSource;
 
-use uv_normalize::PackageName;
-
 use crate::resolver::ForkSet;
 use crate::{DependencyMode, Manifest, ResolverEnvironment};
 
+use uv_normalize::PackageName;
+use uv_pep440::Operator;
+
 #[derive(Debug, Default, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 #[cfg_attr(feature = "clap", derive(clap::ValueEnum))]
@@ -84,6 +85,9 @@ impl PrereleaseStrategy {
 
                     if specifier
                         .iter()
+                        .filter(|spec| {
+                            !matches!(spec.operator(), Operator::NotEqual | Operator::NotEqualStar)
+                        })
                         .any(uv_pep440::VersionSpecifier::any_prerelease)
                     {
                         packages.add(&requirement, ());

crates/uv/tests/it/pip_compile.rs

@@ -12687,6 +12687,42 @@ fn unsupported_requires_python_dynamic_metadata() -> Result<()> {
     Ok(())
 }
 
+#[test]
+fn negation_not_imply_prerelease() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let requirements_in = context.temp_dir.child("requirements.in");
+    requirements_in.write_str("flask<2.0.1, !=2.0.0rc1")?;
+    uv_snapshot!(context
+        .pip_compile()
+        .arg("requirements.in"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated by uv via the following command:
+    #    uv pip compile --cache-dir [CACHE_DIR] requirements.in
+    click==8.1.7
+        # via flask
+    flask==2.0.0
+        # via -r requirements.in
+    itsdangerous==2.1.2
+        # via flask
+    jinja2==3.1.3
+        # via flask
+    markupsafe==2.1.5
+        # via
+        #   jinja2
+        #   werkzeug
+    werkzeug==3.0.1
+        # via flask
+
+    ----- stderr -----
+    Resolved 6 packages in [TIME]
+    "###);
+
+    Ok(())
+}
+
 /// Perform a universal resolution with a constraint, where the constraint itself has a marker.
 #[test]
 fn lowest_direct_fork() -> Result<()> {