prune stale plugin capability overrides (#14862)

* prune stale plugin capability overrides

* fix: configure button still shows (n) modified configs after removing

* fix: add slicing_pipeline_plugin to deep_diff

src/slic3r/plugin/PluginConfig.hpp

@@ -8,7 +8,9 @@
 #include <map>
 #include <mutex>
 #include <optional>
+#include <set>
 #include <string>
+#include <utility>
 #include <vector>
 
 #define PLUGIN_CONFIG_DIR "config.json"
@@ -16,6 +18,7 @@
 namespace Slic3r {
 
 class Preset;
+class DynamicConfig;
 struct CapabilityConfigEntry
 {
     PluginCapabilityId id;
@@ -35,6 +38,9 @@ public:
     bool                                 contains(const PluginCapabilityId& id) const;
     bool                                 upsert(CapabilityConfigEntry entry);
     bool                                 erase(const PluginCapabilityId& id);
+    // Drops every entry whose (type, name) is not in `referenced`, e.g. capabilities a preset's
+    // plugin-backed options no longer name. Returns true if anything was removed.
+    bool                                 prune_unreferenced(const std::set<std::pair<PluginCapabilityType, std::string>>& referenced);
     bool                                 empty() const;
     nlohmann::json                       serialize_entries() const;
     nlohmann::json                       root_json() const;
@@ -50,6 +56,14 @@ std::string plugin_overrides_of(const Preset& preset);
 bool parse_plugin_overrides(const std::string& raw, CapabilityConfigDocument& document, std::string& error);
 std::string serialize_plugin_overrides(const CapabilityConfigDocument& document);
 
+// Drops plugin_config_overrides entries for capabilities no longer named by any plugin-backed
+// option's current value in `config` (e.g. slicing_pipeline_plugin cleared or switched to a
+// different capability), and writes the result back if anything changed. Called wherever a
+// plugin-backed option's value changes, so a saved preset never carries configuration for a
+// capability it no longer references. Returns true if `config` was modified, so a caller holding a
+// GUI field over PLUGIN_OVERRIDES_OPTION_KEY knows it must refresh that field's displayed value.
+bool prune_stale_plugin_overrides(DynamicConfig& config);
+
 struct EffectiveCapabilityConfig
 {
     PluginCapabilityId id;