From 447116fdba8b7f458dc8ad4666ce3e7725b2d347 Mon Sep 17 00:00:00 2001
From: Cosimo Lupo <clupo@google.com>
Date: Wed, 19 May 2021 20:05:36 +0100
Subject: [PATCH] Add test to reproduce issue 2312

---
 ...S_SinglePos_no_value_issue_2312.subset.ttx | 234 ++++++
 .../GPOS_SinglePos_no_value_issue_2312.ttx    | 689 ++++++++++++++++++
 Tests/subset/subset_test.py                   |  13 +
 3 files changed, 936 insertions(+)
 create mode 100644 Tests/subset/data/GPOS_SinglePos_no_value_issue_2312.subset.ttx
 create mode 100644 Tests/subset/data/GPOS_SinglePos_no_value_issue_2312.ttx

diff --git a/Tests/subset/data/GPOS_SinglePos_no_value_issue_2312.subset.ttx b/Tests/subset/data/GPOS_SinglePos_no_value_issue_2312.subset.ttx
new file mode 100644
index 000000000..7eee95fe4
--- /dev/null
+++ b/Tests/subset/data/GPOS_SinglePos_no_value_issue_2312.subset.ttx
@@ -0,0 +1,234 @@
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+    </LookupList>
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diff --git a/Tests/subset/data/GPOS_SinglePos_no_value_issue_2312.ttx b/Tests/subset/data/GPOS_SinglePos_no_value_issue_2312.ttx
new file mode 100644
index 000000000..914963723
--- /dev/null
+++ b/Tests/subset/data/GPOS_SinglePos_no_value_issue_2312.ttx
@@ -0,0 +1,689 @@
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+<ttFont sfntVersion="\x00\x01\x00\x00" ttLibVersion="4.24">
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+    <GlyphID id="1" name="ra-sidd"/>
+    <GlyphID id="2" name="ra-sidd.ini"/>
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+      Noto Sans Siddham Regular
+    </namerecord>
+    <namerecord nameID="5" platformID="3" platEncID="1" langID="0x409">
+      Version 2.001
+    </namerecord>
+    <namerecord nameID="6" platformID="3" platEncID="1" langID="0x409">
+      NotoSansSiddham-Regular
+    </namerecord>
+  </name>
+
+  <post>
+    <formatType value="2.0"/>
+    <italicAngle value="0.0"/>
+    <underlinePosition value="-100"/>
+    <underlineThickness value="50"/>
+    <isFixedPitch value="0"/>
+    <minMemType42 value="0"/>
+    <maxMemType42 value="0"/>
+    <minMemType1 value="0"/>
+    <maxMemType1 value="0"/>
+    <psNames>
+      <!-- This file uses unique glyph names based on the information
+           found in the 'post' table. Since these names might not be unique,
+           we have to invent artificial names in case of clashes. In order to
+           be able to retain the original information, we need a name to
+           ps name mapping for those cases where they differ. That's what
+           you see below.
+            -->
+    </psNames>
+    <extraNames>
+      <!-- following are the name that are not taken from the standard Mac glyph order -->
+      <psName name="ra-sidd"/>
+      <psName name="ra-sidd.ini"/>
+      <psName name="ra-sidd.iniThird"/>
+      <psName name="r-sidd.med.ra"/>
+    </extraNames>
+  </post>
+
+  <GDEF>
+    <Version value="0x00010002"/>
+    <GlyphClassDef>
+      <ClassDef glyph="r-sidd.med.ra" class="3"/>
+      <ClassDef glyph="ra-sidd" class="1"/>
+      <ClassDef glyph="ra-sidd.ini" class="1"/>
+      <ClassDef glyph="ra-sidd.iniThird" class="1"/>
+    </GlyphClassDef>
+    <MarkGlyphSetsDef>
+      <MarkSetTableFormat value="1"/>
+      <!-- MarkSetCount=3 -->
+      <Coverage index="0">
+        <Glyph value="r-sidd.med.ra"/>
+      </Coverage>
+      <Coverage index="1">
+      </Coverage>
+      <Coverage index="2">
+        <Glyph value="r-sidd.med.ra"/>
+      </Coverage>
+    </MarkGlyphSetsDef>
+  </GDEF>
+
+  <GPOS>
+    <Version value="0x00010000"/>
+    <ScriptList>
+      <!-- ScriptCount=2 -->
+      <ScriptRecord index="0">
+        <ScriptTag value="DFLT"/>
+        <Script>
+          <DefaultLangSys>
+            <ReqFeatureIndex value="65535"/>
+            <!-- FeatureCount=3 -->
+            <FeatureIndex index="0" value="1"/>
+            <FeatureIndex index="1" value="3"/>
+            <FeatureIndex index="2" value="4"/>
+          </DefaultLangSys>
+          <!-- LangSysCount=0 -->
+        </Script>
+      </ScriptRecord>
+      <ScriptRecord index="1">
+        <ScriptTag value="sidd"/>
+        <Script>
+          <DefaultLangSys>
+            <ReqFeatureIndex value="65535"/>
+            <!-- FeatureCount=4 -->
+            <FeatureIndex index="0" value="0"/>
+            <FeatureIndex index="1" value="2"/>
+            <FeatureIndex index="2" value="3"/>
+            <FeatureIndex index="3" value="4"/>
+          </DefaultLangSys>
+          <!-- LangSysCount=0 -->
+        </Script>
+      </ScriptRecord>
+    </ScriptList>
+    <FeatureList>
+      <!-- FeatureCount=5 -->
+      <FeatureRecord index="0">
+        <FeatureTag value="dist"/>
+        <Feature>
+          <!-- LookupCount=1 -->
+          <LookupListIndex index="0" value="2"/>
+        </Feature>
+      </FeatureRecord>
+      <FeatureRecord index="1">
+        <FeatureTag value="kern"/>
+        <Feature>
+          <!-- LookupCount=2 -->
+          <LookupListIndex index="0" value="0"/>
+          <LookupListIndex index="1" value="2"/>
+        </Feature>
+      </FeatureRecord>
+      <FeatureRecord index="2">
+        <FeatureTag value="kern"/>
+        <Feature>
+          <!-- LookupCount=1 -->
+          <LookupListIndex index="0" value="0"/>
+        </Feature>
+      </FeatureRecord>
+      <FeatureRecord index="3">
+        <FeatureTag value="mark"/>
+        <Feature>
+          <!-- LookupCount=1 -->
+          <LookupListIndex index="0" value="3"/>
+        </Feature>
+      </FeatureRecord>
+      <FeatureRecord index="4">
+        <FeatureTag value="mkmk"/>
+        <Feature>
+          <!-- LookupCount=1 -->
+          <LookupListIndex index="0" value="4"/>
+        </Feature>
+      </FeatureRecord>
+    </FeatureList>
+    <LookupList>
+      <!-- LookupCount=5 -->
+      <Lookup index="0">
+        <LookupType value="8"/>
+        <LookupFlag value="0"/>
+        <!-- SubTableCount=1 -->
+        <ChainContextPos index="0" Format="3">
+          <!-- BacktrackGlyphCount=0 -->
+          <!-- InputGlyphCount=1 -->
+          <InputCoverage index="0">
+            <Glyph value="ra-sidd.ini"/>
+            <Glyph value="ra-sidd.iniThird"/>
+          </InputCoverage>
+          <!-- LookAheadGlyphCount=1 -->
+          <LookAheadCoverage index="0">
+            <Glyph value="r-sidd.med.ra"/>
+          </LookAheadCoverage>
+          <!-- PosCount=1 -->
+          <PosLookupRecord index="0">
+            <SequenceIndex value="0"/>
+            <LookupListIndex value="1"/>
+          </PosLookupRecord>
+        </ChainContextPos>
+      </Lookup>
+      <Lookup index="1">
+        <LookupType value="1"/>
+        <LookupFlag value="0"/>
+        <!-- SubTableCount=1 -->
+        <SinglePos index="0" Format="1">
+          <Coverage>
+            <Glyph value="ra-sidd.ini"/>
+            <Glyph value="ra-sidd.iniThird"/>
+          </Coverage>
+          <ValueFormat value="0"/>
+        </SinglePos>
+      </Lookup>
+      <Lookup index="2">
+        <LookupType value="2"/>
+        <LookupFlag value="0"/>
+        <!-- SubTableCount=1 -->
+        <PairPos index="0" Format="2">
+          <Coverage>
+            <Glyph value="ra-sidd"/>
+          </Coverage>
+          <ValueFormat1 value="4"/>
+          <ValueFormat2 value="0"/>
+          <ClassDef1>
+          </ClassDef1>
+          <ClassDef2>
+            <ClassDef glyph="r-sidd.med.ra" class="1"/>
+            <ClassDef glyph="ra-sidd" class="1"/>
+            <ClassDef glyph="ra-sidd.ini" class="1"/>
+            <ClassDef glyph="ra-sidd.iniThird" class="1"/>
+          </ClassDef2>
+          <!-- Class1Count=1 -->
+          <!-- Class2Count=2 -->
+          <Class1Record index="0">
+            <Class2Record index="0">
+              <Value1 XAdvance="0"/>
+            </Class2Record>
+            <Class2Record index="1">
+              <Value1 XAdvance="0"/>
+            </Class2Record>
+          </Class1Record>
+        </PairPos>
+      </Lookup>
+      <Lookup index="3">
+        <LookupType value="4"/>
+        <LookupFlag value="0"/>
+        <!-- SubTableCount=1 -->
+        <MarkBasePos index="0" Format="1">
+          <MarkCoverage>
+            <Glyph value="r-sidd.med.ra"/>
+          </MarkCoverage>
+          <BaseCoverage>
+            <Glyph value="ra-sidd"/>
+            <Glyph value="ra-sidd.ini"/>
+            <Glyph value="ra-sidd.iniThird"/>
+          </BaseCoverage>
+          <!-- ClassCount=1 -->
+          <MarkArray>
+            <!-- MarkCount=1 -->
+            <MarkRecord index="0">
+              <Class value="0"/>
+              <MarkAnchor Format="1">
+                <XCoordinate value="258"/>
+                <YCoordinate value="435"/>
+              </MarkAnchor>
+            </MarkRecord>
+          </MarkArray>
+          <BaseArray>
+            <!-- BaseCount=3 -->
+            <BaseRecord index="0">
+              <BaseAnchor index="0" Format="1">
+                <XCoordinate value="257"/>
+                <YCoordinate value="-53"/>
+              </BaseAnchor>
+            </BaseRecord>
+            <BaseRecord index="1">
+              <BaseAnchor index="0" Format="1">
+                <XCoordinate value="258"/>
+                <YCoordinate value="435"/>
+              </BaseAnchor>
+            </BaseRecord>
+            <BaseRecord index="2">
+              <BaseAnchor index="0" Format="1">
+                <XCoordinate value="258"/>
+                <YCoordinate value="435"/>
+              </BaseAnchor>
+            </BaseRecord>
+          </BaseArray>
+        </MarkBasePos>
+      </Lookup>
+      <Lookup index="4">
+        <LookupType value="6"/>
+        <LookupFlag value="16"/><!-- useMarkFilteringSet -->
+        <!-- SubTableCount=1 -->
+        <MarkMarkPos index="0" Format="1">
+          <Mark1Coverage>
+            <Glyph value="r-sidd.med.ra"/>
+          </Mark1Coverage>
+          <Mark2Coverage>
+            <Glyph value="r-sidd.med.ra"/>
+          </Mark2Coverage>
+          <!-- ClassCount=1 -->
+          <Mark1Array>
+            <!-- MarkCount=1 -->
+            <MarkRecord index="0">
+              <Class value="0"/>
+              <MarkAnchor Format="1">
+                <XCoordinate value="258"/>
+                <YCoordinate value="435"/>
+              </MarkAnchor>
+            </MarkRecord>
+          </Mark1Array>
+          <Mark2Array>
+            <!-- Mark2Count=1 -->
+            <Mark2Record index="0">
+              <Mark2Anchor index="0" Format="1">
+                <XCoordinate value="258"/>
+                <YCoordinate value="235"/>
+              </Mark2Anchor>
+            </Mark2Record>
+          </Mark2Array>
+        </MarkMarkPos>
+        <MarkFilteringSet value="0"/>
+      </Lookup>
+    </LookupList>
+  </GPOS>
+
+  <GSUB>
+    <Version value="0x00010000"/>
+    <ScriptList>
+      <!-- ScriptCount=2 -->
+      <ScriptRecord index="0">
+        <ScriptTag value="DFLT"/>
+        <Script>
+          <DefaultLangSys>
+            <ReqFeatureIndex value="65535"/>
+            <!-- FeatureCount=0 -->
+          </DefaultLangSys>
+          <!-- LangSysCount=0 -->
+        </Script>
+      </ScriptRecord>
+      <ScriptRecord index="1">
+        <ScriptTag value="sidd"/>
+        <Script>
+          <DefaultLangSys>
+            <ReqFeatureIndex value="65535"/>
+            <!-- FeatureCount=2 -->
+            <FeatureIndex index="0" value="0"/>
+            <FeatureIndex index="1" value="1"/>
+          </DefaultLangSys>
+          <!-- LangSysCount=0 -->
+        </Script>
+      </ScriptRecord>
+    </ScriptList>
+    <FeatureList>
+      <!-- FeatureCount=2 -->
+      <FeatureRecord index="0">
+        <FeatureTag value="pref"/>
+        <Feature>
+          <!-- LookupCount=0 -->
+        </Feature>
+      </FeatureRecord>
+      <FeatureRecord index="1">
+        <FeatureTag value="psts"/>
+        <Feature>
+          <!-- LookupCount=1 -->
+          <LookupListIndex index="0" value="0"/>
+        </Feature>
+      </FeatureRecord>
+    </FeatureList>
+    <LookupList>
+      <!-- LookupCount=2 -->
+      <Lookup index="0">
+        <LookupType value="6"/>
+        <LookupFlag value="0"/>
+        <!-- SubTableCount=1 -->
+        <ChainContextSubst index="0" Format="3">
+          <!-- BacktrackGlyphCount=0 -->
+          <!-- InputGlyphCount=1 -->
+          <InputCoverage index="0">
+            <Glyph value="ra-sidd.ini"/>
+          </InputCoverage>
+          <!-- LookAheadGlyphCount=1 -->
+          <LookAheadCoverage index="0">
+            <Glyph value="r-sidd.med.ra"/>
+          </LookAheadCoverage>
+          <!-- SubstCount=1 -->
+          <SubstLookupRecord index="0">
+            <SequenceIndex value="0"/>
+            <LookupListIndex value="1"/>
+          </SubstLookupRecord>
+        </ChainContextSubst>
+      </Lookup>
+      <Lookup index="1">
+        <LookupType value="1"/>
+        <LookupFlag value="0"/>
+        <!-- SubTableCount=1 -->
+        <SingleSubst index="0">
+          <Substitution in="ra-sidd.ini" out="ra-sidd.iniThird"/>
+        </SingleSubst>
+      </Lookup>
+    </LookupList>
+  </GSUB>
+
+</ttFont>
diff --git a/Tests/subset/subset_test.py b/Tests/subset/subset_test.py
index 0c39eb011..1294ca586 100644
--- a/Tests/subset/subset_test.py
+++ b/Tests/subset/subset_test.py
@@ -793,6 +793,19 @@ class SubsetTest(unittest.TestCase):
                 subsetfont = TTFont(subsetpath)
                 self.expect_ttx(subsetfont, expected_ttx, ["GPOS"])
 
+    def test_GPOS_SinglePos_prune_post_subset_no_value(self):
+        _, fontpath = self.compile_font(
+            self.getpath("GPOS_SinglePos_no_value_issue_2312.ttx"), ".ttf"
+        )
+        subsetpath = self.temp_path(".ttf")
+        subset.main([fontpath, "*", "--glyph-names", "--output-file=%s" % subsetpath])
+        subsetfont = TTFont(subsetpath)
+        self.expect_ttx(
+            subsetfont,
+            self.getpath("GPOS_SinglePos_no_value_issue_2312.subset.ttx"),
+            ["GlyphOrder", "GPOS"],
+        )
+
 
 @pytest.fixture
 def featureVarsTestFont():