helper to copy a precise from a source

Author: Eh2406

src/cargo/core/dependency.rs

@@ -352,9 +352,7 @@ impl Dependency {
         // Only update the `precise` of this source to preserve other
         // information about dependency's source which may not otherwise be
         // tested during equality/hashing.
-        me.source_id = me
-            .source_id
-            .with_precise(id.source_id().precise().map(|s| s.to_string()));
+        me.source_id = me.source_id.with_precise_from(id.source_id());
         self
     }
 

src/cargo/core/source_id.rs

@@ -494,6 +494,14 @@ impl SourceId {
         })
     }
 
+    /// Creates a new `SourceId` from this source with the `precise` from some other `SourceId`.
+    pub fn with_precise_from(self, v: Self) -> SourceId {
+        SourceId::wrap(SourceIdInner {
+            precise: v.inner.precise.clone(),
+            ..(*self.inner).clone()
+        })
+    }
+
     /// When updating a lock file on a version using `cargo update --precise`
     /// the requested version is stored in the precise field.
     /// On a registry dependency we also need to keep track of the package that

src/cargo/ops/resolve.rs

@@ -389,12 +389,8 @@ pub fn resolve_with_previous<'cfg>(
                         }) {
                             Some(id_using_default) => {
                                 let id_using_master = id_using_default.with_source_id(
-                                    dep.source_id().with_precise(
-                                        id_using_default
-                                            .source_id()
-                                            .precise()
-                                            .map(|s| s.to_string()),
-                                    ),
+                                    dep.source_id()
+                                        .with_precise_from(id_using_default.source_id()),
                                 );
 
                                 let mut locked_dep = dep.clone();
@@ -796,7 +792,7 @@ fn master_branch_git_source(id: PackageId, resolve: &Resolve) -> Option<PackageI
             let new_source =
                 SourceId::for_git(source.url(), GitReference::Branch("master".to_string()))
                     .unwrap()
-                    .with_precise(source.precise().map(|s| s.to_string()));
+                    .with_precise_from(source);
             return Some(id.with_source_id(new_source));
         }
     }

src/cargo/sources/config.rs

@@ -145,7 +145,7 @@ impl<'cfg> SourceConfigMap<'cfg> {
                 // Attempt to interpret the source name as an alt registry name
                 if let Ok(alt_id) = SourceId::alt_registry(self.config, name) {
                     debug!("following pointer to registry {}", name);
-                    break alt_id.with_precise(id.precise().map(str::to_string));
+                    break alt_id.with_precise_from(id);
                 }
                 bail!(
                     "could not find a configured source with the \
@@ -163,7 +163,7 @@ impl<'cfg> SourceConfigMap<'cfg> {
                 }
                 None if id == cfg.id => return id.load(self.config, yanked_whitelist),
                 None => {
-                    break cfg.id.with_precise(id.precise().map(|s| s.to_string()));
+                    break cfg.id.with_precise_from(id);
                 }
             }
             debug!("following pointer to {}", name);