Any have metadata value when empty Fixes #5113 (#8603)

Previously, when we saw the Item was empty, we'd jump out early. Fortunately, we already special-cased Count, and it turns out we can do the same with AnyHaveMetadataValue. Fixes #5113.
dotnet · Mar 28, 2023 · da690cf · da690cf
1 parent ea90db2
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diff --git a/documentation/wiki/ChangeWaves.md b/documentation/wiki/ChangeWaves.md
@@ -28,6 +28,7 @@ A wave of features is set to "rotate out" (i.e. become standard functionality) t
 - [Eliminate project string cache](https://github.com/dotnet/msbuild/pull/7965)
 - [Log an error when no provided search path for an import exists](https://github.com/dotnet/msbuild/pull/8095)
 - [Log assembly loads](https://github.com/dotnet/msbuild/pull/8316)
+- [AnyHaveMetadataValue returns false when passed an empty list](https://github.com/dotnet/msbuild/pull/8603)
 
 ### 17.4
 - [Respect deps.json when loading assemblies](https://github.com/dotnet/msbuild/pull/7520)

diff --git a/src/Build.UnitTests/Evaluation/Expander_Tests.cs b/src/Build.UnitTests/Evaluation/Expander_Tests.cs
@@ -222,6 +222,18 @@ public void ExpandItemVectorFunctionsAnyHaveMetadataValue()
             Assert.Equal("false", itemsFalse[0].EvaluatedInclude);
         }
 
+        [Fact]
+        public void ExpandEmptyItemVectorFunctionWithAnyHaveMetadataValue()
+        {
+            ProjectInstance project = ProjectHelpers.CreateEmptyProjectInstance();
+            Expander<ProjectPropertyInstance, ProjectItemInstance> expander = CreateItemFunctionExpander();
+            ProjectItemInstanceFactory itemFactory = new ProjectItemInstanceFactory(project, "i");
+
+            IList<ProjectItemInstance> itemsEmpty = expander.ExpandIntoItemsLeaveEscaped("@(unsetItem->AnyHaveMetadataValue('Metadatum', 'value'))", itemFactory, ExpanderOptions.ExpandItems, MockElementLocation.Instance);
+            ProjectItemInstance pii = itemsEmpty.ShouldHaveSingleItem<ProjectItemInstance>();
+            pii.EvaluatedInclude.ShouldBe("false");
+        }
+
         /// <summary>
         /// Expand an item vector function Metadata()->DirectoryName()->Distinct()
         /// </summary>

diff --git a/src/Build/Evaluation/Expander.cs b/src/Build/Evaluation/Expander.cs
@@ -1946,11 +1946,16 @@ private static class ItemExpander
                 // If there are no items of the given type, then bail out early
                 if (itemsOfType.Count == 0)
                 {
-                    // .. but only if there isn't a function "Count()", since that will want to return something (zero) for an empty list
+                    // ... but only if there isn't a function "Count", since that will want to return something (zero) for an empty list
                     if (expressionCapture.Captures?.Any(capture => string.Equals(capture.FunctionName, "Count", StringComparison.OrdinalIgnoreCase)) != true)
                     {
-                        itemsFromCapture = new List<Pair<string, S>>();
-                        return false;
+                        // ...or a function "AnyHaveMetadataValue", since that will want to return false for an empty list.
+                        if (!ChangeWaves.AreFeaturesEnabled(ChangeWaves.Wave17_6) ||
+                            expressionCapture.Captures?.Any(capture => string.Equals(capture.FunctionName, "AnyHaveMetadataValue", StringComparison.OrdinalIgnoreCase)) != true)
+                        {
+                            itemsFromCapture = new List<Pair<string, S>>();
+                            return false;
+                        }
                     }
                 }