Refactor LocalManifest::get_dependency_version

The new method get_dependencies doesn't take a dep key but instead
returns all deps. We'll sometimes need this in coming patches, and when
we don't need it it's easy to have the caller filter.

Author: sadmac7000

src/cargo/ops/cargo_add/mod.rs

@@ -648,8 +648,11 @@ fn get_existing_dependency(
     }
 
     let mut possible: Vec<_> = manifest
-        .get_dependency_versions(dep_key, ws, unstable_features)
-        .map(|(path, dep)| {
+        .get_dependencies(ws, unstable_features)
+        .filter_map(|(key, path, dep)| {
+            if key.as_str() != dep_key {
+                return None;
+            }
             let key = if path == *section {
                 (Key::Existing, true)
             } else if dep.is_err() {
@@ -662,7 +665,7 @@ fn get_existing_dependency(
                 };
                 (key, path.target().is_some())
             };
-            (key, dep)
+            Some((key, dep))
         })
         .collect();
     possible.sort_by_key(|(key, _)| *key);

src/cargo/util/toml_mut/manifest.rs

@@ -327,12 +327,11 @@ impl LocalManifest {
     }
 
     /// Lookup a dependency.
-    pub fn get_dependency_versions<'s>(
+    pub fn get_dependencies<'s>(
         &'s self,
-        dep_key: &'s str,
         ws: &'s Workspace<'_>,
         unstable_features: &'s Features,
-    ) -> impl Iterator<Item = (DepTable, CargoResult<Dependency>)> + 's {
+    ) -> impl Iterator<Item = (String, DepTable, CargoResult<Dependency>)> + 's {
         let crate_root = self.path.parent().expect("manifest path is absolute");
         self.get_sections()
             .into_iter()
@@ -341,13 +340,7 @@ impl LocalManifest {
                 Some(
                     table
                         .into_iter()
-                        .filter_map(|(key, item)| {
-                            if key.as_str() == dep_key {
-                                Some((table_path.clone(), key, item))
-                            } else {
-                                None
-                            }
-                        })
+                        .map(|(key, item)| (table_path.clone(), key, item))
                         .collect::<Vec<_>>(),
                 )
             })
@@ -361,7 +354,7 @@ impl LocalManifest {
                     &dep_key,
                     &dep_item,
                 );
-                (table_path, dep)
+                (dep_key, table_path, dep)
             })
     }