SF-3656 Fix argument out of range error when using two training sources (#3597)

Author: pmachapman

src/SIL.XForge.Scripture/Services/MachineProjectService.cs

@@ -1286,11 +1286,40 @@ .. corporaSyncInfo
         {
             for (int j = 0; j < trainingCorpusConfig.SourceFilters?.Count; j++)
             {
-                if (trainingCorpusConfig.TargetFilters?[j] is not null)
+                if (trainingCorpusConfig.TargetFilters is not null)
                 {
-                    trainingCorpusConfig.TargetFilters[j].ScriptureRange = trainingCorpusConfig
-                        .SourceFilters[j]
-                        .ScriptureRange;
+                    if (
+                        trainingCorpusConfig.TargetFilters.Count > j
+                        && trainingCorpusConfig.TargetFilters[j] is not null
+                    )
+                    {
+                        // Set the scripture range for the matching target filter
+                        trainingCorpusConfig.TargetFilters[j].ScriptureRange = trainingCorpusConfig
+                            .SourceFilters[j]
+                            .ScriptureRange;
+                    }
+                    else if (trainingCorpusConfig.TargetFilters[0] is not null)
+                    {
+                        // There is no matching target filter, so update the first target filter.
+                        // Merge the two scripture ranges by getting the distinct book names.
+                        // This will also preserve any chapter ranges that are specified.
+                        trainingCorpusConfig.TargetFilters[0].ScriptureRange = string.Join(
+                            ';',
+                            string.Join(
+                                    ';',
+                                    trainingCorpusConfig.TargetFilters[0].ScriptureRange ?? string.Empty,
+                                    trainingCorpusConfig.SourceFilters[j].ScriptureRange ?? string.Empty
+                                )
+                                .Split(';', StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries)
+                                .Distinct()
+                        );
+
+                        // Ensure that the scripture range is null if it is empty, so that all books will be trained on
+                        if (string.IsNullOrWhiteSpace(trainingCorpusConfig.TargetFilters[0].ScriptureRange))
+                        {
+                            trainingCorpusConfig.TargetFilters[0].ScriptureRange = null;
+                        }
+                    }
                 }
             }
         }

test/SIL.XForge.Scripture.Tests/Services/MachineProjectServiceTests.cs

@@ -50,6 +50,7 @@ public class MachineProjectServiceTests
     private const string Corpus02 = "corpus02";
     private const string Corpus03 = "corpus03";
     private const string Corpus04 = "corpus04";
+    private const string Corpus05 = "corpus04";
     private const string Data01 = "data01";
     private const string File01 = "file01";
     private const string File02 = "file02";
@@ -1908,6 +1909,7 @@ public void GetTranslationBuildConfig_TranslationScriptureRangesAndTrainingScrip
         const string project01ScriptureRange = "MAT;MRK";
         // No scripture range is supported for target pre-translate translation (project02)
         const string project03ScriptureRange = "LUK;JHN";
+        const string project04ScriptureRange = "ACT;ROM";
         var buildConfig = new BuildConfig
         {
             TranslationScriptureRanges =
@@ -1917,6 +1919,7 @@ public void GetTranslationBuildConfig_TranslationScriptureRangesAndTrainingScrip
             TrainingScriptureRanges =
             [
                 new ProjectScriptureRange { ProjectId = Project03, ScriptureRange = project03ScriptureRange },
+                new ProjectScriptureRange { ProjectId = Project04, ScriptureRange = project04ScriptureRange },
             ],
         };
         List<ServalCorpusSyncInfo> corporaSyncInfo =
@@ -1945,6 +1948,13 @@ public void GetTranslationBuildConfig_TranslationScriptureRangesAndTrainingScrip
             new ServalCorpusSyncInfo
             {
                 CorpusId = Corpus04,
+                IsSource = true,
+                ParallelCorpusId = ParallelCorpus02,
+                ProjectId = Project04,
+            },
+            new ServalCorpusSyncInfo
+            {
+                CorpusId = Corpus05,
                 IsSource = false,
                 ParallelCorpusId = ParallelCorpus02,
                 ProjectId = Project02,
@@ -1973,7 +1983,7 @@ public void GetTranslationBuildConfig_TranslationScriptureRangesAndTrainingScrip
                 .ScriptureRange
         );
         Assert.AreEqual(
-            project03ScriptureRange,
+            string.Join(';', project03ScriptureRange, project04ScriptureRange),
             actual
                 .TrainOn!.Single(c => c.ParallelCorpusId == ParallelCorpus02)
                 .TargetFilters!.Single(f => f.CorpusId == Corpus04)