HermitCrab: keep final-template pruning on when only lexical entries are partial

src/SIL.Machine.Morphology.HermitCrab/AnalysisAffixTemplateRule.cs

@@ -41,10 +41,10 @@ public IEnumerable<Word> Apply(Word input)
             if (_morpher.TraceManager.IsTracing)
                 _morpher.TraceManager.BeginUnapplyTemplate(_template, input);
 
-            // Do not allow a final template to unapply if we don't need to worry about partials
+            // Do not allow a final template to unapply if we don't need to worry about partial rules
             // and a non-template was last unapplied.
             if (
-                (!_morpher.IsPartial || _morpher.AlwaysEnforceFinalTemplates)
+                (!_morpher.HasPartialRules || _morpher.AlwaysEnforceFinalTemplates)
                 && input.FinalTemplateState == FinalTemplateState.NonTemplate
                 && _template.IsFinal
             )

src/SIL.Machine.Morphology.HermitCrab/Morpher.cs

@@ -62,7 +62,7 @@ public Morpher(ITraceManager traceManager, Language lang, int maxDegreeOfParalle
             RuleSelector = rule => true;
 
             _morphemes = new ReadOnlyObservableCollection<Morpheme>(morphemes);
-            IsPartial = GetPartialMorphemes().Count() > 0;
+            HasPartialRules = GetPartialMorphemes().Any(morpheme => !(morpheme is LexEntry));
         }
 
         public IEnumerable<Morpheme> GetPartialMorphemes()
@@ -98,9 +98,10 @@ public ITraceManager TraceManager
         public bool MergeEquivalentAnalyses { get; set; }
 
         /// <summary>
-        /// A Morpher is partial if any of the elements are partial.
+        /// True if any morpheme other than a <see cref="LexEntry"/> is partial. Analysis may prune a final
+        /// template that follows a non-template rule only when this is false.
         /// </summary>
-        public bool IsPartial { get; }
+        public bool HasPartialRules { get; }
 
         /// <summary>
         /// Enforce final templates even if some of the morphemes were partial.
@@ -491,8 +492,6 @@ private IEnumerable<Word> LexicalGuess(Word input)
                             SyntacticFeatureStruct = input.SyntacticFeatureStruct,
                             Stratum = input.Stratum,
                         };
-                        // Don't update Morpher.IsPartial even if lexEntry.IsPartial is true.
-                        // We don't mind if final templates are filtered during analysis in this case.
                         lexEntry.Allomorphs.Add(root);
                         // Point the root allomorph to the lexical pattern in FieldWorks.
                         if (lexicalPattern.Morpheme != null)

src/SIL.Machine.Morphology.HermitCrab/MorphologicalRules/AnalysisAffixProcessRule.cs

@@ -80,7 +80,7 @@ out FeatureStruct syntacticFS
 
                         outWord.SyntacticFeatureStruct = syntacticFS;
                     }
-                    if (!_morpher.IsPartial || _morpher.AlwaysEnforceFinalTemplates)
+                    if (!_morpher.HasPartialRules || _morpher.AlwaysEnforceFinalTemplates)
                     {
                         if (!_rule.GetIsCliticRule())
                         {

tests/SIL.Machine.Morphology.HermitCrab.Tests/AffixTemplateTests.cs

@@ -473,7 +473,7 @@ public void EarlyPruningOfFinalTemplate()
 
         // Verify early pruning of final template.
         var morpher = new Morpher(TraceManager, Language);
-        Assert.That(morpher.IsPartial, Is.True);
+        Assert.That(morpher.GetPartialMorphemes(), Is.Not.Empty);
         morpher.AlwaysEnforceFinalTemplates = true;
         TraceManager.IsTracing = true;
         AssertMorphsEqual(morpher.ParseWord("sagdv", out object trace));
@@ -501,6 +501,79 @@ public void EarlyPruningOfFinalTemplate()
         AssertMorphsEqual(morpher.ParseWord("sagdmis"), "32 PAST 53 PL");
     }
 
+    [Test]
+    public void PartialLexicalEntryDoesNotDisableEarlyPruningOfFinalTemplate()
+    {
+        var any = FeatureStruct.New().Symbol(HCFeatureSystem.Segment).Value;
+        var verb = FeatureStruct.New(Language.SyntacticFeatureSystem).Symbol("V").Value;
+
+        AffixProcessRule CreateSuffix(string name, string gloss, string suffix)
+        {
+            var rule = new AffixProcessRule
+            {
+                Name = name,
+                Gloss = gloss,
+                RequiredSyntacticFeatureStruct = verb.Clone(),
+            };
+            rule.Allomorphs.Add(
+                new AffixProcessAllomorph
+                {
+                    Lhs = { Pattern<Word, ShapeNode>.New("1").Annotation(any).OneOrMore.Value },
+                    Rhs = { new CopyFromInput("1"), new InsertSegments(Table3, suffix) },
+                }
+            );
+            return rule;
+        }
+
+        var edSuffix = CreateSuffix("ed_suffix", "PAST", "d");
+        var verbTemplate = new AffixTemplate { Name = "verb", RequiredSyntacticFeatureStruct = verb.Clone() };
+        verbTemplate.Slots.Add(new AffixTemplateSlot(edSuffix));
+        Morphophonemic.AffixTemplates.Add(verbTemplate);
+        var nominalizer = CreateSuffix("nominalizer", "NOM", "v");
+        Morphophonemic.MorphologicalRules.Add(nominalizer);
+        var partialRoot = AddEntry("partial_root", verb.Clone(), Morphophonemic, "sab");
+        partialRoot.IsPartial = true;
+        try
+        {
+            // The test grammar already has a partial entry, so only the rules decide the prune.
+            var morpher = new Morpher(TraceManager, Language);
+            Assert.That(morpher.GetPartialMorphemes(), Is.Not.Empty);
+            Assert.That(morpher.HasPartialRules, Is.False);
+            Assert.That(morpher.AlwaysEnforceFinalTemplates, Is.False);
+            TraceManager.IsTracing = true;
+            AssertMorphsEqual(morpher.ParseWord("sagdv", out object trace));
+            Assert.That(
+                GetFailureDepth((Trace)trace, FailureReason.NonPartialRuleProhibitedAfterFinalTemplate),
+                Is.EqualTo(2)
+            );
+            TraceManager.IsTracing = false;
+            AssertMorphsEqual(morpher.ParseWord("sagd"), "32 PAST");
+
+            // No template applies to a partial root, so pruning loses nothing for it.
+            AssertMorphsEqual(morpher.ParseWord("sab"), "partial_root");
+            AssertMorphsEqual(morpher.ParseWord("sabd"));
+            AssertMorphsEqual(morpher.ParseWord("sabdv"));
+            AssertMorphsEqual(morpher.ParseWord("sabv"), "partial_root NOM");
+
+            // A partial rule still turns the prune off, and what it licenses after a final template survives.
+            nominalizer.IsPartial = true;
+            morpher = new Morpher(TraceManager, Language);
+            Assert.That(morpher.HasPartialRules, Is.True);
+            TraceManager.IsTracing = true;
+            AssertMorphsEqual(morpher.ParseWord("sagdv", out trace), "32 PAST NOM");
+            Assert.That(
+                GetFailureDepth((Trace)trace, FailureReason.NonPartialRuleProhibitedAfterFinalTemplate),
+                Is.EqualTo(0)
+            );
+            TraceManager.IsTracing = false;
+        }
+        finally
+        {
+            Morphophonemic.Entries.Remove(partialRoot);
+            Entries.Remove("partial_root");
+        }
+    }
+
     private static int GetFailureDepth(Trace trace, FailureReason reason)
     {
         if (trace == null)

tests/SIL.Machine.Morphology.HermitCrab.Tests/MorphologicalRules/PruneDisagreeingCopiesTests.cs

@@ -228,7 +228,11 @@ public void PartialMorphemesParseTheSameWithAndWithoutPruning(bool alwaysEnforce
         string[] Parse(bool pruneCopies, string word)
         {
             Morpher morpher = CreateMorpher(pruneCopies);
-            Assert.That(morpher.IsPartial, Is.True, "entry 54 has an empty syntactic feature structure");
+            Assert.That(
+                morpher.GetPartialMorphemes(),
+                Is.Not.Empty,
+                "entry 54 has an empty syntactic feature structure"
+            );
             morpher.AlwaysEnforceFinalTemplates = alwaysEnforceFinalTemplates;
             return ParseGlosses(morpher, word);
         }