update: silent failure on non-matching package specs with --breaking

src/cargo/ops/cargo_update.rs

@@ -238,6 +238,9 @@ pub fn upgrade_manifests(
     let mut registry = ws.package_registry()?;
     registry.lock_patches();
 
+    // Track which specs have been matched to detect non-existent packages
+    let mut matched_specs = HashSet::new();
+
     for member in ws.members_mut().sorted() {
         debug!("upgrading manifest for `{}`", member.name());
 
@@ -252,11 +255,38 @@ pub fn upgrade_manifests(
                     &mut registry,
                     &mut upgrades,
                     &mut upgrade_messages,
+                    &mut matched_specs,
                     d,
                 )
             })?;
     }
 
+    // Check if any specs were not matched against direct dependencies
+    if !to_update.is_empty() {
+        // Load the lockfile to check for transitive dependencies
+        let previous_resolve = ops::load_pkg_lockfile(ws)?;
+
+        for spec in &to_update {
+            if !matched_specs.contains(spec) {
+                // Spec didn't match any direct dependencies
+                // Check if it matches any package in the lockfile (including transitive deps)
+                let matches_lockfile = if let Some(ref resolve) = previous_resolve {
+                    spec.query(resolve.iter()).is_ok()
+                } else {
+                    false
+                };
+
+                if !matches_lockfile {
+                    // Spec doesn't match any package at all
+                    anyhow::bail!(
+                        "package ID specification `{}` did not match any packages",
+                        spec
+                    );
+                }
+            }
+        }
+    }
+
     Ok(upgrades)
 }
 
@@ -266,18 +296,30 @@ fn upgrade_dependency(
     registry: &mut PackageRegistry<'_>,
     upgrades: &mut UpgradeMap,
     upgrade_messages: &mut HashSet<String>,
+    matched_specs: &mut HashSet<PackageIdSpec>,
     dependency: Dependency,
 ) -> CargoResult<Dependency> {
     let name = dependency.package_name();
     let renamed_to = dependency.name_in_toml();
 
+    if !to_update.is_empty() {
+        // Check if any spec matches this dependency by name
+        for spec in to_update.iter() {
+            if spec.name() == name.as_str() {
+                // Mark this spec as matched (exists in workspace)
+                matched_specs.insert(spec.clone());
+            }
+        }
+    }
+
     if name != renamed_to {
         trace!("skipping dependency renamed from `{name}` to `{renamed_to}`");
         return Ok(dependency);
     }
 
-    if !to_update.is_empty()
-        && !to_update.iter().any(|spec| {
+    if !to_update.is_empty() {
+        // Check if this dependency should be upgraded based on the specs
+        let should_upgrade = to_update.iter().any(|spec| {
             spec.name() == name.as_str()
                 && dependency.source_id().is_registry()
                 && spec
@@ -286,10 +328,12 @@ fn upgrade_dependency(
                 && spec
                     .version()
                     .map_or(true, |v| dependency.version_req().matches(&v))
-        })
-    {
-        trace!("skipping dependency `{name}` not selected for upgrading");
-        return Ok(dependency);
+        });
+
+        if !should_upgrade {
+            trace!("skipping dependency `{name}` not selected for upgrading");
+            return Ok(dependency);
+        }
     }
 
     if !dependency.source_id().is_registry() {

tests/testsuite/update.rs

@@ -2750,3 +2750,48 @@ Caused by:
 "#]])
         .run();
 }
+
+#[cargo_test]
+fn update_breaking_missing_package_error() {
+    Package::new("bar", "1.0.0").publish();
+
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+                [package]
+                name = "foo"
+                version = "0.0.1"
+                edition = "2015"
+                authors = []
+
+                [dependencies]
+                bar = "1.0"
+            "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("generate-lockfile").run();
+
+    // Test that --breaking reports an error for non-existent packages
+    p.cargo("update -Zunstable-options --breaking no_such_crate")
+        .masquerade_as_nightly_cargo(&["update-breaking"])
+        .with_status(101)
+        .with_stderr_data(str![[r#"
+[ERROR] package ID specification `no_such_crate` did not match any packages
+
+"#]])
+        .run();
+
+    // Test with multiple packages, one valid and one invalid
+    p.cargo("update -Zunstable-options --breaking bar no_such_crate")
+        .masquerade_as_nightly_cargo(&["update-breaking"])
+        .with_status(101)
+        .with_stderr_data(str![[r#"
+[UPDATING] `dummy-registry` index
+[ERROR] package ID specification `no_such_crate` did not match any packages
+
+"#]])
+        .run();
+}