From: Timm Bäder <mail@baedert.org>
Date: Tue, 1 Nov 2016 09:48:57 +0000 (+0100)
Subject: Method: Keep track of return statements with nullable values
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2f299ac1df853b339e6dd63aa3aadfe50a8564d1;p=thirdparty%2Fvala.git

Method: Keep track of return statements with nullable values

If the return type of a method is marked nullable, check that at least
one of the return statements also may return null.
---

diff --git a/vala/valamethod.vala b/vala/valamethod.vala
index f0f19809f..ec35e00b5 100644
--- a/vala/valamethod.vala
+++ b/vala/valamethod.vala
@@ -185,6 +185,8 @@ public class Vala.Method : Subroutine, Callable {
 
 	public int yield_count { get; set; }
 
+	public bool has_nullable_return_statement { get; set; default = false;}
+
 	private List<Parameter> parameters = new ArrayList<Parameter> ();
 	private List<Expression> preconditions;
 	private List<Expression> postconditions;
@@ -759,6 +761,12 @@ public class Vala.Method : Subroutine, Callable {
 
 		if (body != null) {
 			body.check (context);
+			if (!this.overrides && this.base_interface_method == null &&
+			    this.return_type.nullable && !this.has_nullable_return_statement) {
+				// The return type of the method is marked nullable but none
+				// of the return statements return a nullable type
+				Report.warning (this.source_reference, "Return type of %s is marked nullable but none of its return statements return a nullable value".printf (this.get_full_name ()));
+			}
 		}
 
 		if (context.analyzer.current_struct != null) {
diff --git a/vala/valareturnstatement.vala b/vala/valareturnstatement.vala
index e407aec4a..d1f349e51 100644
--- a/vala/valareturnstatement.vala
+++ b/vala/valareturnstatement.vala
@@ -138,6 +138,11 @@ public class Vala.ReturnStatement : CodeNode, Statement {
 			Report.warning (source_reference, "`null' incompatible with return type `%s`".printf (context.analyzer.current_return_type.to_string ()));
 		}
 
+		if (return_expression.value_type.nullable &&
+		    context.analyzer.current_method != null) {
+			context.analyzer.current_method.has_nullable_return_statement = true;
+		}
+
 		add_error_types (return_expression.get_error_types ());
 
 		return !error;