Merge pull request #658 from googlefonts/use-missingcomponenterror

Better error message when component is missing

Lib/glyphsLib/builder/components.py

@@ -15,6 +15,7 @@
 
 import logging
 
+from fontTools.pens.basePen import MissingComponentError
 from fontTools.pens.recordingPen import DecomposingRecordingPen
 from glyphsLib.classes import GSBackgroundLayer
 from glyphsLib.types import Transform
@@ -109,7 +110,13 @@ def to_ufo_components_background_decompose(self, ufo_glyph, layer):
 
     rpen = DecomposingRecordingPen(glyphSet=layers)
     for component in layer.components:
-        component.draw(rpen)
+        try:
+            component.draw(rpen)
+        except MissingComponentError as e:
+            raise MissingComponentError(
+                f"Glyph '{ufo_glyph.name}', background layer: component "
+                f"'{component.name}' points to a non-existent glyph."
+            ) from e
     rpen.replay(ufo_glyph.getPen())
 
 

requirements-dev.txt

@@ -4,25 +4,55 @@
 #
 #    pip-compile requirements-dev.in
 #
-appdirs==1.4.4            # via fs
-attrs==20.3.0             # via pytest
-coverage==5.3             # via -r requirements-dev.in
-defcon==0.7.2             # via -r requirements-dev.in
-fonttools[ufo,unicode]==4.17.1  # via defcon
-fs==2.4.11                # via fonttools
-iniconfig==1.1.1          # via pytest
-lxml==4.6.2               # via xmldiff
-packaging==20.7           # via pytest
-pluggy==0.13.1            # via pytest
-py==1.9.0                 # via pytest
-pyparsing==2.4.7          # via packaging
-pytest-randomly==3.5.0    # via -r requirements-dev.in
-pytest==6.1.2             # via -r requirements-dev.in, pytest-randomly
-pytz==2020.4              # via fs
-six==1.15.0               # via fs, xmldiff
-toml==0.10.2              # via pytest
-ufonormalizer==0.4.2      # via -r requirements-dev.in
-xmldiff==2.4              # via -r requirements-dev.in
+
+appdirs==1.4.4
+    # via fs
+atomicwrites==1.4.0
+    # via pytest
+attrs==20.3.0
+    # via pytest
+colorama==0.4.4
+    # via pytest
+coverage==5.4
+    # via -r requirements-dev.in
+defcon==0.7.2
+    # via -r requirements-dev.in
+fonttools[ufo,unicode]==4.19.0
+    # via defcon
+fs==2.4.12
+    # via fonttools
+iniconfig==1.1.1
+    # via pytest
+lxml==4.6.2
+    # via xmldiff
+packaging==20.8
+    # via pytest
+pluggy==0.13.1
+    # via pytest
+py==1.10.0
+    # via pytest
+pyparsing==2.4.7
+    # via packaging
+pytest-randomly==3.5.0
+    # via -r requirements-dev.in
+pytest==6.2.2
+    # via
+    #   -r requirements-dev.in
+    #   pytest-randomly
+pytz==2020.5
+    # via fs
+six==1.15.0
+    # via
+    #   fs
+    #   xmldiff
+toml==0.10.2
+    # via pytest
+ufonormalizer==0.5.3
+    # via -r requirements-dev.in
+unicodedata2==13.0.0.post2
+    # via fonttools
+xmldiff==2.4
+    # via -r requirements-dev.in
 
 # The following packages are considered to be unsafe in a requirements file:
 # setuptools

requirements.txt

@@ -4,13 +4,25 @@
 #
 #    pip-compile setup.py
 #
-appdirs==1.4.4            # via fs
-attrs==20.3.0             # via ufolib2
-fonttools[ufo,unicode]==4.17.1  # via glyphsLib (setup.py), ufolib2
-fs==2.4.11                # via fonttools
-pytz==2020.4              # via fs
-six==1.15.0               # via fs
-ufolib2==0.10.0           # via glyphsLib (setup.py)
+
+appdirs==1.4.4
+    # via fs
+attrs==20.3.0
+    # via ufolib2
+fonttools[ufo,unicode]==4.19.0
+    # via
+    #   glyphsLib (setup.py)
+    #   ufolib2
+fs==2.4.12
+    # via fonttools
+pytz==2020.5
+    # via fs
+six==1.15.0
+    # via fs
+ufolib2==0.11.1
+    # via glyphsLib (setup.py)
+unicodedata2==13.0.0.post2
+    # via fonttools
 
 # The following packages are considered to be unsafe in a requirements file:
 # setuptools

setup.cfg

@@ -35,7 +35,7 @@ install_requires =
     # Synchronize with requirements.in until
     # https://github.com/jazzband/pip-tools/issues/1047 is implemented.
     ufoLib2 >= 0.6.2
-    fonttools[ufo,unicode] >= 4.6.0
+    fonttools[ufo,unicode] >= 4.19.0
     importlib_resources; python_version < '3.7'
 
 [options.extras_require]

tests/builder/components_test.py

@@ -1,5 +1,9 @@
+import pytest
+from fontTools.pens.basePen import MissingComponentError
+
 import glyphsLib
 from glyphsLib import to_designspace
+from glyphsLib.classes import GSComponent
 
 
 def test_background_component_decompose(datadir):
@@ -35,3 +39,13 @@ def test_background_component_decompose(datadir):
         ufo_bd.layers["Apr 27 20, 17:59.background"]["B"].contours
         == ufo_bd["A"].contours
     )
+
+
+def test_background_component_decompose_missing(datadir):
+    font = glyphsLib.GSFont(str(datadir.join("Recursion.glyphs")))
+
+    layer = font.glyphs["B"].layers["DB4D7D04-C02D-48DE-811E-03AA03052DD2"].background
+    layer.components.append(GSComponent("xxx"))
+
+    with pytest.raises(MissingComponentError):
+        to_designspace(font)