From 086cd345e8d3e78901b963a8fdc0c5d74efc3a7a Mon Sep 17 00:00:00 2001
From: Rico Tzschichholz <ricotz@ubuntu.com>
Date: Tue, 19 May 2020 14:29:06 +0200
Subject: [PATCH] girwriter: Evaluate and output non literal enum-value if it
 is a simple constant

This avoids the output of "(null)" in the generated GIR for these cases.

Fixes https://gitlab.gnome.org/GNOME/vala/issues/996
---
 codegen/valagirwriter.vala               | 13 +++++++++----
 tests/girwriter/GirTest-1.0.gir-expected |  5 +++++
 tests/girwriter/girtest.vala             |  6 ++++++
 tests/girwriter/girtest.vapi-expected    |  6 ++++++
 4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/codegen/valagirwriter.vala b/codegen/valagirwriter.vala
index 0198cc908..d00824d29 100644
--- a/codegen/valagirwriter.vala
+++ b/codegen/valagirwriter.vala
@@ -823,7 +823,7 @@ public class Vala.GIRWriter : CodeVisitor {
 		var en = (Enum) hierarchy[0];
 		buffer.append_printf ("<member name=\"%s\" c:identifier=\"%s\"", ev.name.down (), get_ccode_name (ev));
 		if (ev.value != null) {
-			string value = literal_expression_to_value_string (ev.value);
+			string? value = literal_expression_to_value_string (ev.value);
 			buffer.append_printf (" value=\"%s\"", value);
 		} else {
 			if (en.is_flags) {
@@ -884,7 +884,7 @@ public class Vala.GIRWriter : CodeVisitor {
 		write_indent ();
 		buffer.append_printf ("<member name=\"%s\" c:identifier=\"%s\"", ecode.name.down (), get_ccode_name (ecode));
 		if (ecode.value != null) {
-			string value = literal_expression_to_value_string (ecode.value);
+			string? value = literal_expression_to_value_string (ecode.value);
 			buffer.append_printf (" value=\"%s\"", value);
 		} else {
 			buffer.append_printf (" value=\"%d\"", enum_value++);
@@ -917,7 +917,7 @@ public class Vala.GIRWriter : CodeVisitor {
 
 		//TODO Add better constant evaluation
 		var initializer = c.value;
-		string value = literal_expression_to_value_string (initializer);
+		string? value = literal_expression_to_value_string (initializer, false);
 
 		write_indent ();
 		buffer.append_printf ("<constant name=\"%s\" c:identifier=\"%s\"", c.name, get_ccode_name (c));
@@ -1657,7 +1657,7 @@ public class Vala.GIRWriter : CodeVisitor {
 		return get_full_gir_name (type_symbol);
 	}
 
-	private string? literal_expression_to_value_string (Expression literal) {
+	private string? literal_expression_to_value_string (Expression literal, bool cvalue_fallback = true) {
 		if (literal is StringLiteral) {
 			var lit = literal as StringLiteral;
 			if (lit != null) {
@@ -1680,6 +1680,11 @@ public class Vala.GIRWriter : CodeVisitor {
 					return "-" + ((IntegerLiteral) unary.inner).value;
 				}
 			}
+		} else if (cvalue_fallback) {
+			unowned CCodeExpression? cexpr = get_cvalue (literal);
+			if (cexpr is CCodeConstant) {
+				return ((CCodeConstant) cexpr).name;
+			}
 		}
 		return null;
 	}
diff --git a/tests/girwriter/GirTest-1.0.gir-expected b/tests/girwriter/GirTest-1.0.gir-expected
index 0db2fc636..a71242e9d 100644
--- a/tests/girwriter/GirTest-1.0.gir-expected
+++ b/tests/girwriter/GirTest-1.0.gir-expected
@@ -26,6 +26,11 @@
 	<enumeration name="SkippedFlags" c:type="GirTestSkippedFlags" glib:type-name="GirTestSkippedFlags" glib:get-type="gir_test_skipped_flags_get_type" introspectable="0">
 		<member name="value1" c:identifier="GIR_TEST_SKIPPED_FLAGS_VALUE1" value="0"/>
 	</enumeration>
+	<enumeration name="EnumTest2" c:type="GirTestEnumTest2" glib:type-name="GirTestEnumTest2" glib:get-type="gir_test_enum_test2_get_type">
+		<member name="value1" c:identifier="GIR_TEST_ENUM_TEST2_VALUE1" value="GIR_TEST_ENUM_TEST_VALUE3"/>
+		<member name="value2" c:identifier="GIR_TEST_ENUM_TEST2_VALUE2" value="0"/>
+		<member name="value3" c:identifier="GIR_TEST_ENUM_TEST2_VALUE3" value="4711"/>
+	</enumeration>
 	<enumeration name="ErrorTest" c:type="GirTestErrorTest" glib:error-domain="gir-test-error-test-quark">
 		<member name="failed" c:identifier="GIR_TEST_ERROR_TEST_FAILED" value="0"/>
 		<member name="smelly" c:identifier="GIR_TEST_ERROR_TEST_SMELLY" value="1"/>
diff --git a/tests/girwriter/girtest.vala b/tests/girwriter/girtest.vala
index e9b3d2ae1..e0756e5fb 100644
--- a/tests/girwriter/girtest.vala
+++ b/tests/girwriter/girtest.vala
@@ -306,4 +306,10 @@ namespace GirTest {
 		public void method<K> (K[] param) {
 		}
 	}
+
+	public enum EnumTest2 {
+		VALUE1 = EnumTest.VALUE3,
+		VALUE2,
+		VALUE3 = 4711
+	}
 }
diff --git a/tests/girwriter/girtest.vapi-expected b/tests/girwriter/girtest.vapi-expected
index f92e00d05..b2deaad4e 100644
--- a/tests/girwriter/girtest.vapi-expected
+++ b/tests/girwriter/girtest.vapi-expected
@@ -143,6 +143,12 @@ namespace GirTest {
 		VALUE3
 	}
 	[CCode (cheader_filename = "girtest.h")]
+	public enum EnumTest2 {
+		VALUE1,
+		VALUE2,
+		VALUE3
+	}
+	[CCode (cheader_filename = "girtest.h")]
 	[Flags]
 	public enum FlagsTest {
 		VALUE1,
-- 
2.47.2