From af1e605be27afc79c293fdd0a45e6f6e2edd9054 Mon Sep 17 00:00:00 2001
From: Qunxin Liu <qxliu@google.com>
Date: Fri, 10 Feb 2023 11:08:05 -0800
Subject: [PATCH] [instancer] bug fix

It's possible that length of all_points equals to 4 for non-empty
glyphs: a composite glyph which contains only one child glyph that is
empty.
---
 src/OT/glyf/Glyph.hh                             |   2 +-
 test/subset/data/Makefile.am                     |   1 +
 test/subset/data/Makefile.sources                |   1 +
 ...ono.default.retain-all-codepoint.wght=700.ttf | Bin 0 -> 1264 bytes
 test/subset/data/fonts/RobotoMono.ttf            | Bin 0 -> 1932 bytes
 .../tests/instance_comp_glyph_empty_child.tests  |  11 +++++++++++
 test/subset/meson.build                          |   1 +
 7 files changed, 15 insertions(+), 1 deletion(-)
 create mode 100644 test/subset/data/expected/instance_comp_glyph_empty_child/RobotoMono.default.retain-all-codepoint.wght=700.ttf
 create mode 100644 test/subset/data/fonts/RobotoMono.ttf
 create mode 100644 test/subset/data/tests/instance_comp_glyph_empty_child.tests

diff --git a/src/OT/glyf/Glyph.hh b/src/OT/glyf/Glyph.hh
index 8ca9350d1..5574ae072 100644
--- a/src/OT/glyf/Glyph.hh
+++ b/src/OT/glyf/Glyph.hh
@@ -119,7 +119,7 @@ struct Glyph
                              hb_bytes_t &dest_bytes /* OUT */) const
   {
     GlyphHeader *glyph_header = nullptr;
-    if (!plan->pinned_at_default && type != EMPTY && all_points.length > 4)
+    if (!plan->pinned_at_default && type != EMPTY && all_points.length >= 4)
     {
       glyph_header = (GlyphHeader *) hb_calloc (1, GlyphHeader::static_size);
       if (unlikely (!glyph_header)) return false;
diff --git a/test/subset/data/Makefile.am b/test/subset/data/Makefile.am
index e1747d788..939d468d6 100644
--- a/test/subset/data/Makefile.am
+++ b/test/subset/data/Makefile.am
@@ -63,6 +63,7 @@ EXTRA_DIST += \
 	expected/pin_all_at_default \
 	expected/instance_no_double_free \
 	expected/mvar_full_instance \
+	expected/instance_comp_glyph_empty_child \
 	fonts \
 	profiles \
 	$(NULL)
diff --git a/test/subset/data/Makefile.sources b/test/subset/data/Makefile.sources
index 8a86ad7b1..0b64cad30 100644
--- a/test/subset/data/Makefile.sources
+++ b/test/subset/data/Makefile.sources
@@ -54,6 +54,7 @@ TESTS = \
 	tests/pin_all_at_default.tests \
 	tests/instance_no_double_free.tests \
 	tests/mvar_full_instance.tests \
+	tests/instance_comp_glyph_empty_child.tests \
 	$(NULL)
 
 # TODO: re-enable once colrv1 subsetting is stabilized.
diff --git a/test/subset/data/expected/instance_comp_glyph_empty_child/RobotoMono.default.retain-all-codepoint.wght=700.ttf b/test/subset/data/expected/instance_comp_glyph_empty_child/RobotoMono.default.retain-all-codepoint.wght=700.ttf
new file mode 100644
index 0000000000000000000000000000000000000000..16084db95fa8fc37dc20e9b2167ebcdcea732f6a
GIT binary patch
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diff --git a/test/subset/data/fonts/RobotoMono.ttf b/test/subset/data/fonts/RobotoMono.ttf
new file mode 100644
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diff --git a/test/subset/data/tests/instance_comp_glyph_empty_child.tests b/test/subset/data/tests/instance_comp_glyph_empty_child.tests
new file mode 100644
index 000000000..ed963c948
--- /dev/null
+++ b/test/subset/data/tests/instance_comp_glyph_empty_child.tests
@@ -0,0 +1,11 @@
+FONTS:
+RobotoMono.ttf
+
+PROFILES:
+default.txt
+
+SUBSETS:
+*
+
+INSTANCES:
+wght=700
diff --git a/test/subset/meson.build b/test/subset/meson.build
index 6555b8b13..5c8c1cd26 100644
--- a/test/subset/meson.build
+++ b/test/subset/meson.build
@@ -56,6 +56,7 @@ tests = [
   'instance_feature_variations',
   'instance_no_double_free',
   'mvar_full_instance',
+  'instance_comp_glyph_empty_child',
 ]
 
 repack_tests = [