fix `--only-group` in `uv pip` interface (#10902)

This was an oversight in the implementation, thankfully it appears to be
a simple fix? (My only hesitation is this implementation essentially
claims that --only-group is defacto incompatible with --extra and I
*think* that's the case but I'm not certain.)

crates/uv-requirements/src/source_tree.rs

@@ -98,16 +98,21 @@ impl<'a, Context: BuildContext> SourceTreeResolver<'a, Context> {
             .cloned()
             .collect::<Vec<_>>();
 
-        // Flatten any transitive extras.
-        let mut requirements =
+        let mut requirements = Vec::new();
+
+        // Flatten any transitive extras and include dependencies
+        // (unless something like --only-group was passed)
+        if self.groups.prod() {
+            requirements.extend(
                 FlatRequiresDist::from_requirements(metadata.requires_dist, &metadata.name)
                     .into_iter()
                     .map(|requirement| Requirement {
                         origin: Some(origin.clone()),
                         marker: requirement.marker.simplify_extras(&extras),
                         ..requirement
-                })
-                .collect::<Vec<_>>();
+                    }),
+            );
+        }
 
         // Apply dependency-groups
         for (group_name, group) in &metadata.dependency_groups {

crates/uv/tests/it/pip_compile.rs

@@ -14481,11 +14481,9 @@ fn dependency_group() -> Result<()> {
     # This file was autogenerated by uv via the following command:
     #    uv pip compile --cache-dir [CACHE_DIR] pyproject.toml --only-group bar
     iniconfig==2.0.0
-    typing-extensions==4.10.0
-        # via project (pyproject.toml)
 
     ----- stderr -----
-    Resolved 2 packages in [TIME]
+    Resolved 1 package in [TIME]
     "###);
 
     context = new_context()?;

crates/uv/tests/it/pip_install.rs

@@ -8425,11 +8425,10 @@ fn dependency_group() -> Result<()> {
     ----- stdout -----
 
     ----- stderr -----
-    Resolved 2 packages in [TIME]
-    Prepared 2 packages in [TIME]
-    Installed 2 packages in [TIME]
+    Resolved 1 package in [TIME]
+    Prepared 1 package in [TIME]
+    Installed 1 package in [TIME]
      + iniconfig==2.0.0
-     + typing-extensions==4.10.0
     "###);
 
     context = new_context()?;