WIP vala: Check coverage of switch on enum-type and issue warnings if neededwip/issue/777

Also don't emit implicit default label.

Fixes https://gitlab.gnome.org/GNOME/vala/issues/777

4 files changed, 61 insertions, 1 deletions

diff --git a/codegen/valaccodecontrolflowmodule.vala b/codegen/valaccodecontrolflowmodule.vala
index df31fcef3..a61b3d9fe 100644
--- a/codegen/valaccodecontrolflowmodule.vala
+++ b/codegen/valaccodecontrolflowmodule.vala
@@ -182,7 +182,7 @@ public abstract class Vala.CCodeControlFlowModule : CCodeMethodModule {
 			section.emit (this);
 		}
 
-		if (!has_default) {
+		if (!has_default && !(stmt.expression.value_type is EnumValueType)) {
 			// silence C compiler
 			ccode.add_default ();
 			ccode.add_break ();
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 2f3906f38..af8fe4d74 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -207,6 +207,7 @@ TESTS = \
 	control-flow/missing-return.test \
 	control-flow/nested-conditional.vala \
 	control-flow/switch.vala \
+	control-flow/switch-enum.vala \
 	control-flow/sideeffects.vala \
 	control-flow/unassigned-captured-local-variable.test \
 	control-flow/unassigned-local-block-variable.test \
diff --git a/tests/control-flow/switch-enum.vala b/tests/control-flow/switch-enum.vala
new file mode 100644
index 000000000..51aaaba4c
--- /dev/null
+++ b/tests/control-flow/switch-enum.vala
@@ -0,0 +1,20 @@
+enum Foo {
+	FOO,
+	BAR,
+	MANAM
+}
+
+Foo foo () {
+	Foo foo = Foo.BAR;
+
+	switch (foo) {
+	case Foo.MANAM:
+	case Foo.FOO:
+	case Foo.BAR:
+		return foo;
+	}
+}
+
+void main () {
+	assert (foo () == Foo.BAR);
+}
diff --git a/vala/valaflowanalyzer.vala b/vala/valaflowanalyzer.vala
index ea0df7a83..07ba88998 100644
--- a/vala/valaflowanalyzer.vala
+++ b/vala/valaflowanalyzer.vala
@@ -664,6 +664,14 @@ public class Vala.FlowAnalyzer : CodeVisitor {
 		handle_errors (stmt.expression);
 
 		bool has_default_label = false;
+		bool is_enum_typed = stmt.expression.value_type is EnumValueType;
+
+		unowned Enum? en = null;
+		HashSet<unowned EnumValue>? enum_values = null;
+		if (is_enum_typed) {
+			en = (Enum) ((EnumValueType) stmt.expression.value_type).type_symbol;
+			enum_values = new HashSet<unowned EnumValue> (direct_hash, direct_equal);
+		}
 
 		foreach (SwitchSection section in stmt.get_sections ()) {
 			current_block = new BasicBlock ();
@@ -673,6 +681,17 @@ public class Vala.FlowAnalyzer : CodeVisitor {
 				section_stmt.accept (this);
 			}
 
+			if (is_enum_typed) {
+				foreach (SwitchLabel label in section.get_labels ()) {
+					if (label.expression != null) {
+						unowned EnumValue? val = label.expression.symbol_reference as EnumValue;
+						if (val != null) {
+							enum_values.add (val);
+						}
+					}
+				}
+			}
+
 			if (section.has_default_label ()) {
 				has_default_label = true;
 			}
@@ -688,6 +707,26 @@ public class Vala.FlowAnalyzer : CodeVisitor {
 			}
 		}
 
+		if (is_enum_typed) {
+			// Check if enum-based switching as fully covered, and if so,
+			// handle it like there was a default-label given
+
+			HashSet<EnumValue> remaining_values = new HashSet<EnumValue> ();
+			remaining_values.add_all (en.get_values ());
+			foreach (var val in enum_values) {
+				remaining_values.remove (val);
+			}
+			if (remaining_values.size == 0) {
+				has_default_label = true;
+			} else if (!has_default_label) {
+				string[] missing_vals = {};
+				foreach (var val in remaining_values) {
+					missing_vals += val.name;
+				}
+				Report.warning (stmt.source_reference, "switch does not handle `%s' of enum `%s'".printf (string.joinv ("', `", missing_vals), en.get_full_name ()));
+			}
+		}
+
 		if (!has_default_label) {
 			condition_block.connect (after_switch_block);
 		}