From 3946a24208eb1def61b0dbef16081f7a3f5bdde8 Mon Sep 17 00:00:00 2001
From: Khaled Hosny <khaled@aliftype.com>
Date: Thu, 29 Aug 2024 12:36:49 +0300
Subject: [PATCH] Drop disabled features entirely in minimal mode

Partially fixes https://github.com/googlefonts/glyphsLib/issues/1026 by
handling the case where we are building with fontmake.

When round tripping is desired, the generated UFO when built with ufo2ft
will still have the above issue.
---
 Lib/glyphsLib/builder/features.py |  4 ++++
 tests/builder/features_test.py    | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/Lib/glyphsLib/builder/features.py b/Lib/glyphsLib/builder/features.py
index 5e69d22a4..8a2109adc 100644
--- a/Lib/glyphsLib/builder/features.py
+++ b/Lib/glyphsLib/builder/features.py
@@ -58,6 +58,7 @@ def to_ufo_master_features(self, ufo, master):
             generate_GDEF=self.generate_GDEF,
             master=master,
             expand_includes=self.expand_includes,
+            minimal=self.minimal,
         )
 
 
@@ -84,6 +85,7 @@ def _to_ufo_features(  # noqa: C901
     generate_GDEF: bool = False,
     master: GSFontMaster | None = None,
     expand_includes: bool = False,
+    minimal: bool = False,
 ) -> str:
     """Convert GSFont features, including prefixes and classes, to UFO.
 
@@ -118,6 +120,8 @@ def _to_ufo_features(  # noqa: C901
 
     feature_defs = []
     for feature in font.features:
+        if feature.disabled and minimal:
+            continue
         code = expander.expand(feature.code)
         lines = ["feature %s {" % feature.name]
         notes = feature.notes
diff --git a/tests/builder/features_test.py b/tests/builder/features_test.py
index d08f1bf8b..837f7b918 100644
--- a/tests/builder/features_test.py
+++ b/tests/builder/features_test.py
@@ -600,6 +600,25 @@ def test_roundtrip_feature_prefix_with_only_a_comment(ufo_module):
     assert prefix_r.code == "#include(../family.fea)"
 
 
+def test_drop_disabled_feature(ufo_module):
+    font = to_glyphs([ufo_module.Font()])
+    feature = classes.GSFeature(name="ccmp", code="sub a by a.ccmp1 a.ccmp2;")
+    feature.disabled = True
+    font.features.append(feature)
+
+    feature = classes.GSFeature(name="liga", code="sub f i by f_i;")
+    font.features.append(feature)
+
+    (ufo,) = to_ufos(font, ufo_module=ufo_module, minimal=True)
+    assert ufo.features.text == dedent(
+        """\
+        feature liga {
+        sub f i by f_i;
+        } liga;
+    """
+    )
+
+
 @pytest.fixture
 def ufo_with_GDEF(ufo_module):
     ufo = ufo_module.Font()