makeHardcodeGsettingsPatch: Add support for `schemaExistsFunction`

evolution-ews introduced a check for optional schemas, which would skip our hardcoded code paths.
https://gitlab.gnome.org/GNOME/evolution-ews/-/commit/a0c514bd345c67fe0fd2ed6ef48a25649b1f4d8e

Let’s update the semantic patch to also replace the invocations of specified `schemaExistsFunction` for known schemas with `true`.

pkgs/build-support/make-hardcode-gsettings-patch/default.nix

···
     For example, `{ "org.gnome.evolution" = "EVOLUTION_SCHEMA_PATH"; }`
     hardcodes looking for `org.gnome.evolution` into `@EVOLUTION_SCHEMA_PATH@`.
 
+  - `schemaExistsFunction`: name of the function that is used for checking
+    if optional schema exists. Its invocation will be replaced with TRUE
+    for known schemas.
+
   - `patches`: A list of patches to apply before generating the patch.
 
   Example:
···
   src,
   patches ? [ ],
   schemaIdToVariableMapping,
+  schemaExistsFunction ? null,
 }:
 
 runCommand "hardcode-gsettings.patch"
···
     patchPhase
     set -x
     cp ${builtins.toFile "glib-schema-to-var.json" (builtins.toJSON schemaIdToVariableMapping)} ./glib-schema-to-var.json
+    cp ${builtins.toFile "glib-schema-exists-function.json" (builtins.toJSON schemaExistsFunction)} ./glib-schema-exists-function.json
     git init
     git add -A
     spatch --sp-file "${./hardcode-gsettings.cocci}" --dir . --in-place

pkgs/build-support/make-hardcode-gsettings-patch/hardcode-gsettings.cocci

···
         return f'"@{schema_to_var[schema_id]}@"'
     raise Exception(f"Unknown schema path {schema_id!r}, please add it to ./glib-schema-to-var.json")
 
+
+@script:python schema_exists_fn@
+fn;
+@@
+import json
+
+with open("./glib-schema-exists-function.json") as fn_file:
+    if (fn := json.load(fn_file)):
+        coccinelle.fn = fn
+
+
 @find_cpp_constants@
 identifier const_name;
 expression val;
···
 +   schema = g_settings_schema_source_lookup(schema_source, SCHEMA_ID, FALSE);
 +   settings = g_settings_new_full(schema, NULL, PATH);
 +}
+
+
+@replace_schema_exists_fns depends on ever record_cpp_constants || never record_cpp_constants@
+// We want to run after #define constants have been collected but even if there are no #defines.
+expression SCHEMA_ID;
+identifier schema_exists_fn.fn;
+@@
+-fn(SCHEMA_ID)
++true

pkgs/test/make-hardcode-gsettings-patch/default.nix

···
       expected,
       src,
       patches ? [ ],
-      schemaIdToVariableMapping,
+      args,
     }:
 
     let
-      patch = makeHardcodeGsettingsPatch ({
-        inherit src schemaIdToVariableMapping;
-        inherit patches;
-      });
+      patch = makeHardcodeGsettingsPatch (
+        args
+        // {
+          inherit src patches;
+        }
+      );
     in
     runCommandLocal "makeHardcodeGsettingsPatch-tests-${name}"
 
···
   basic = mkTest {
     name = "basic";
     src = ./fixtures/example-project;
-    schemaIdToVariableMapping = {
-      "org.gnome.evolution-data-server.addressbook" = "EDS";
-      "org.gnome.evolution.calendar" = "EVO";
-      "org.gnome.seahorse.nautilus.window" = "SEANAUT";
+    args = {
+      schemaIdToVariableMapping = {
+        "org.gnome.evolution-data-server.addressbook" = "EDS";
+        "org.gnome.evolution.calendar" = "EVO";
+        "org.gnome.seahorse.nautilus.window" = "SEANAUT";
+      };
     };
     expected = ./fixtures/example-project-patched;
   };
···
       # Avoid using wrapper function, which the generator cannot handle.
       ./fixtures/example-project-wrapped-settings-constructor-resolve.patch
     ];
-    schemaIdToVariableMapping = {
-      "org.gnome.evolution-data-server.addressbook" = "EDS";
+    args = {
+      schemaIdToVariableMapping = {
+        "org.gnome.evolution-data-server.addressbook" = "EDS";
+      };
     };
     expected = ./fixtures/example-project-wrapped-settings-constructor-patched;
   };
+
+  existsFn = mkTest {
+    name = "exists-fn";
+    src = ./fixtures/example-project;
+    args = {
+      schemaIdToVariableMapping = {
+        "org.gnome.evolution-data-server.addressbook" = "EDS";
+        "org.gnome.evolution.calendar" = "EVO";
+        "org.gnome.seahorse.nautilus.window" = "SEANAUT";
+      };
+      schemaExistsFunction = "e_ews_common_utils_gsettings_schema_exists";
+    };
+    expected = ./fixtures/example-project-patched-with-exists-fn;
+  };
+
 }

pkgs/test/make-hardcode-gsettings-patch/fixtures/example-project-patched-with-exists-fn/main.c

···
+#include <gio/gio.h>
+#include <glib-object.h>
+
+void schema_id_literal() {
+  GSettings *settings;
+  {
+    g_autoptr(GSettingsSchemaSource) schema_source;
+    g_autoptr(GSettingsSchema) schema;
+    schema_source = g_settings_schema_source_new_from_directory("@EDS@", g_settings_schema_source_get_default(), TRUE, NULL);
+    schema = g_settings_schema_source_lookup(schema_source, "org.gnome.evolution-data-server.addressbook", FALSE);
+    settings = g_settings_new_full(schema, NULL, NULL);
+  }
+  g_object_unref(settings);
+}
+
+#define SELF_UID_PATH_ID "org.gnome.evolution-data-server.addressbook"
+int schema_id_from_constant() {
+  GSettings *settings;
+  {
+    g_autoptr(GSettingsSchemaSource) schema_source;
+    g_autoptr(GSettingsSchema) schema;
+    schema_source = g_settings_schema_source_new_from_directory("@EDS@", g_settings_schema_source_get_default(), TRUE, NULL);
+    schema = g_settings_schema_source_lookup(schema_source, SELF_UID_PATH_ID, FALSE);
+    settings = g_settings_new_full(schema, NULL, NULL);
+  }
+  g_object_unref(settings);
+}
+
+void schema_id_autoptr() {
+  g_autoptr(GSettings) settings = NULL;
+  {
+    g_autoptr(GSettingsSchemaSource) schema_source;
+    g_autoptr(GSettingsSchema) schema;
+    schema_source = g_settings_schema_source_new_from_directory("@EVO@", g_settings_schema_source_get_default(), TRUE, NULL);
+    schema = g_settings_schema_source_lookup(schema_source, "org.gnome.evolution.calendar", FALSE);
+    settings = g_settings_new_full(schema, NULL, NULL);
+  }
+}
+
+void schema_id_with_backend() {
+  GSettings *settings;
+  {
+    g_autoptr(GSettingsSchemaSource) schema_source;
+    g_autoptr(GSettingsSchema) schema;
+    schema_source = g_settings_schema_source_new_from_directory("@EDS@", g_settings_schema_source_get_default(), TRUE, NULL);
+    schema = g_settings_schema_source_lookup(schema_source, "org.gnome.evolution-data-server.addressbook", FALSE);
+    settings = g_settings_new_full(schema, g_settings_backend_get_default(), NULL);
+  }
+  g_object_unref(settings);
+}
+
+void schema_id_with_backend_and_path() {
+  GSettings *settings;
+  {
+    g_autoptr(GSettingsSchemaSource) schema_source;
+    g_autoptr(GSettingsSchema) schema;
+    schema_source = g_settings_schema_source_new_from_directory("@SEANAUT@", g_settings_schema_source_get_default(), TRUE, NULL);
+    schema = g_settings_schema_source_lookup(schema_source, "org.gnome.seahorse.nautilus.window", FALSE);
+    settings = g_settings_new_full(schema, g_settings_backend_get_default(), "/org/gnome/seahorse/nautilus/windows/123/");
+  }
+  g_object_unref(settings);
+}
+
+void schema_id_with_path() {
+  GSettings *settings;
+  {
+    g_autoptr(GSettingsSchemaSource) schema_source;
+    g_autoptr(GSettingsSchema) schema;
+    schema_source = g_settings_schema_source_new_from_directory("@SEANAUT@", g_settings_schema_source_get_default(), TRUE, NULL);
+    schema = g_settings_schema_source_lookup(schema_source, "org.gnome.seahorse.nautilus.window", FALSE);
+    settings = g_settings_new_full(schema, NULL, "/org/gnome/seahorse/nautilus/windows/123/");
+  }
+  g_object_unref(settings);
+}
+
+void exists_fn_guard() {
+  if (!true) {
+    return;
+  }
+
+  g_autoptr(GSettings) settings = NULL;
+  {
+    g_autoptr(GSettingsSchemaSource) schema_source;
+    g_autoptr(GSettingsSchema) schema;
+    schema_source = g_settings_schema_source_new_from_directory("@EVO@", g_settings_schema_source_get_default(), TRUE, NULL);
+    schema = g_settings_schema_source_lookup(schema_source, "org.gnome.evolution.calendar", FALSE);
+    settings = g_settings_new_full(schema, NULL, NULL);
+  }
+}
+
+void exists_fn_nested() {
+  if (true) {
+    g_autoptr(GSettings) settings = NULL;
+    {
+      g_autoptr(GSettingsSchemaSource) schema_source;
+      g_autoptr(GSettingsSchema) schema;
+      schema_source = g_settings_schema_source_new_from_directory("@EVO@", g_settings_schema_source_get_default(), TRUE, NULL);
+      schema = g_settings_schema_source_lookup(schema_source, "org.gnome.evolution.calendar", FALSE);
+      settings = g_settings_new_full(schema, NULL, NULL);
+    }
+  }
+}
+
+void exists_fn_unknown() {
+  if (true) {
+    g_autoptr(GSettings) settings = NULL;
+    {
+      g_autoptr(GSettingsSchemaSource) schema_source;
+      g_autoptr(GSettingsSchema) schema;
+      schema_source = g_settings_schema_source_new_from_directory("@EVO@", g_settings_schema_source_get_default(), TRUE, NULL);
+      schema = g_settings_schema_source_lookup(schema_source, "org.gnome.evolution.calendar", FALSE);
+      settings = g_settings_new_full(schema, NULL, NULL);
+    }
+  }
+}
+
+int main() {
+  schema_id_literal();
+  schema_id_from_constant();
+  schema_id_autoptr();
+  schema_id_with_backend();
+  schema_id_with_backend_and_path();
+  schema_id_with_path();
+  exists_fn_guard();
+  exists_fn_nested();
+  exists_fn_unknown();
+
+  return 0;
+}

pkgs/test/make-hardcode-gsettings-patch/fixtures/example-project-patched/main.c

···
   g_object_unref(settings);
 }
 
+void exists_fn_guard() {
+  if (!e_ews_common_utils_gsettings_schema_exists("org.gnome.evolution.calendar")) {
+    return;
+  }
+
+  g_autoptr(GSettings) settings = NULL;
+  {
+    g_autoptr(GSettingsSchemaSource) schema_source;
+    g_autoptr(GSettingsSchema) schema;
+    schema_source = g_settings_schema_source_new_from_directory("@EVO@", g_settings_schema_source_get_default(), TRUE, NULL);
+    schema = g_settings_schema_source_lookup(schema_source, "org.gnome.evolution.calendar", FALSE);
+    settings = g_settings_new_full(schema, NULL, NULL);
+  }
+}
+
+void exists_fn_nested() {
+  if (e_ews_common_utils_gsettings_schema_exists("org.gnome.evolution.calendar")) {
+    g_autoptr(GSettings) settings = NULL;
+    {
+      g_autoptr(GSettingsSchemaSource) schema_source;
+      g_autoptr(GSettingsSchema) schema;
+      schema_source = g_settings_schema_source_new_from_directory("@EVO@", g_settings_schema_source_get_default(), TRUE, NULL);
+      schema = g_settings_schema_source_lookup(schema_source, "org.gnome.evolution.calendar", FALSE);
+      settings = g_settings_new_full(schema, NULL, NULL);
+    }
+  }
+}
+
+void exists_fn_unknown() {
+  if (e_ews_common_utils_gsettings_schema_exists("org.gnome.foo")) {
+    g_autoptr(GSettings) settings = NULL;
+    {
+      g_autoptr(GSettingsSchemaSource) schema_source;
+      g_autoptr(GSettingsSchema) schema;
+      schema_source = g_settings_schema_source_new_from_directory("@EVO@", g_settings_schema_source_get_default(), TRUE, NULL);
+      schema = g_settings_schema_source_lookup(schema_source, "org.gnome.evolution.calendar", FALSE);
+      settings = g_settings_new_full(schema, NULL, NULL);
+    }
+  }
+}
+
 int main() {
   schema_id_literal();
   schema_id_from_constant();
···
   schema_id_with_backend();
   schema_id_with_backend_and_path();
   schema_id_with_path();
+  exists_fn_guard();
+  exists_fn_nested();
+  exists_fn_unknown();
 
   return 0;
 }

pkgs/test/make-hardcode-gsettings-patch/fixtures/example-project/main.c

···
   g_object_unref(settings);
 }
 
+void exists_fn_guard() {
+  if (!e_ews_common_utils_gsettings_schema_exists("org.gnome.evolution.calendar")) {
+    return;
+  }
+
+  g_autoptr(GSettings) settings = NULL;
+  settings = g_settings_new("org.gnome.evolution.calendar");
+}
+
+void exists_fn_nested() {
+  if (e_ews_common_utils_gsettings_schema_exists("org.gnome.evolution.calendar")) {
+    g_autoptr(GSettings) settings = NULL;
+    settings = g_settings_new("org.gnome.evolution.calendar");
+  }
+}
+
+void exists_fn_unknown() {
+  if (e_ews_common_utils_gsettings_schema_exists("org.gnome.foo")) {
+    g_autoptr(GSettings) settings = NULL;
+    settings = g_settings_new("org.gnome.evolution.calendar");
+  }
+}
+
 int main() {
   schema_id_literal();
   schema_id_from_constant();
···
   schema_id_with_backend();
   schema_id_with_backend_and_path();
   schema_id_with_path();
+  exists_fn_guard();
+  exists_fn_nested();
+  exists_fn_unknown();
 
   return 0;
 }