cargo-rail: fix(unify): don’t fail --check when only optional features are reported (exit code fuckery)

Author: loadingalias

.config/rail.toml

@@ -49,6 +49,7 @@ detect_undeclared_features = true  # Detect features borrowed via Cargo unificat
 fix_undeclared_features = true  # Auto-fix borrowed features (default: true)
 skip_undeclared_patterns = ["default", "std", "alloc", "*_backend", "*_impl"]  # Features to skip in undeclared detection (glob patterns)
 sort_dependencies = true  # Sort deps alphabetically (default: true)
+enforce_msrv_inheritance = false  # Ensure members inherit workspace rust-version
 
 
 [release]

src/cargo/unify_analyzer.rs

@@ -556,6 +556,9 @@ impl UnifyAnalyzer {
     // Run validation
     let validation_results = self.validate_targets()?;
 
+    // Defensive cleanup: avoid representing "no-op members" as pending changes.
+    member_edits.retain(|_, edits| !edits.is_empty());
+
     Ok(UnificationPlan {
       workspace_deps,
       member_edits,

src/cargo/unify_types.rs

@@ -260,6 +260,24 @@ impl UnificationPlan {
     self.issues.iter().any(|i| i.severity == IssueSeverity::Error)
   }
 
+  /// Total number of concrete member edits planned across the workspace.
+  ///
+  /// Note: `member_edits` may contain empty vectors in edge cases; this returns the
+  /// actual edit count and is the right basis for "would this mutate files?" checks.
+  pub fn member_edit_count(&self) -> usize {
+    self.member_edits.values().map(|v| v.len()).sum()
+  }
+
+  /// Returns true if the plan would mutate manifests or workspace MSRV.
+  ///
+  /// Intentionally ignores informational-only fields like `optional_features`.
+  pub fn has_planned_changes(&self, msrv_write_needed: bool) -> bool {
+    !self.workspace_deps.is_empty()
+      || self.member_edit_count() > 0
+      || !self.transitive_pins.is_empty()
+      || msrv_write_needed
+  }
+
   /// Generates a human-readable summary of the plan
   pub fn summary(&self) -> String {
     let mut s = String::new();
@@ -947,4 +965,33 @@ mod tests {
     // Should NOT contain "borrowed from" when empty
     assert!(!summary.contains("borrowed from"));
   }
+
+  #[test]
+  fn test_member_edit_count_ignores_empty_entries() {
+    let mut member_edits = std::collections::HashMap::new();
+    member_edits.insert("crate-a".to_string(), vec![]);
+
+    let plan = UnificationPlan {
+      workspace_deps: vec![],
+      member_edits,
+      member_paths: std::collections::HashMap::new(),
+      transitive_pins: vec![],
+      validation_results: vec![],
+      issues: vec![],
+      computed_msrv: None,
+      duplicates_cleaned: vec![],
+      pruned_features: vec![],
+      optional_features: vec![OptionalFeature {
+        crate_name: "crate-a".to_string(),
+        feature_name: "serde".to_string(),
+        enables: vec!["serde/derive".to_string()],
+      }],
+      version_mismatches: vec![],
+      unused_deps: vec![],
+      undeclared_features: vec![],
+    };
+
+    assert_eq!(plan.member_edit_count(), 0);
+    assert!(!plan.has_planned_changes(false));
+  }
 }

src/commands/unify.rs

@@ -48,7 +48,7 @@ pub fn run_unify_analyze(
       })).collect::<Vec<_>>(),
       "summary": {
         "workspace_deps_count": plan.workspace_deps.len(),
-        "member_edits_count": plan.member_edits.values().map(|v| v.len()).sum::<usize>(),
+        "member_edits_count": plan.member_edit_count(),
         "members_affected": plan.member_edits.len(),
         "transitive_pins_count": plan.transitive_pins.len(),
         "duplicates_unified": plan.duplicates_cleaned.len(),
@@ -94,10 +94,7 @@ pub fn run_unify_analyze(
   }
 
   // Show diff if requested
-  let has_changes = !plan.member_edits.is_empty()
-    || !plan.workspace_deps.is_empty()
-    || !plan.transitive_pins.is_empty()
-    || msrv_write_needed;
+  let has_changes = plan.has_planned_changes(msrv_write_needed);
   if show_diff && has_changes {
     println!("\nplanned changes:\n");
 
@@ -275,7 +272,7 @@ pub fn run_unify_analyze(
     crate::error!("blocking issues prevent unification");
     return Err(RailError::message("blocking issues prevent unification"));
   } else if has_changes {
-    let total_edits: usize = plan.member_edits.values().map(|v| v.len()).sum();
+    let total_edits = plan.member_edit_count();
     if !plan.workspace_deps.is_empty() || !plan.transitive_pins.is_empty() || msrv_write_needed {
       println!(
         "\nready: {} dependencies, {} member edits",
@@ -325,11 +322,7 @@ pub fn run_unify_apply(
     return Err(crate::error::RailError::message("blocking issues prevent unification"));
   }
 
-  if plan.workspace_deps.is_empty()
-    && plan.member_edits.is_empty()
-    && plan.transitive_pins.is_empty()
-    && !msrv_write_needed
-  {
+  if !plan.has_planned_changes(msrv_write_needed) {
     println!("nothing to unify");
     return Ok(());
   }