CodeMining: reuse existing inlined annotations when minings are

unchanged

Add getMinings() accessor methods to CodeMiningLineContentAnnotation and
CodeMiningLineHeaderAnnotation to expose their mining lists. Enhance
findExistingAnnotation() in InlinedAnnotationSupport to accept an
optional
minings parameter and compare existing annotations' minings with new
ones.
This allows reusing existing annotation instances when the mining
content
hasn't changed, avoiding unnecessary annotation recreation and improving
performance.

The change prevents flickering and reduces overhead by preserving
annotation
objects when only their position is being updated during reconciliation,
but
their actual mining data remains identical.

#2786 (comment)

Author: tobias-melcher

bundles/org.eclipse.jface.text/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.jface.text
-Bundle-Version: 3.29.100.qualifier
+Bundle-Version: 3.30.0.qualifier
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
 Export-Package: 

bundles/org.eclipse.jface.text/src/org/eclipse/jface/internal/text/codemining/CodeMiningLineContentAnnotation.java

@@ -216,4 +216,8 @@ public boolean isInVisibleLines() {
 	public final boolean isAfterPosition() {
 		return afterPosition;
 	}
+
+	public List<ICodeMining> getMinings() {
+		return fMinings;
+	}
 }

bundles/org.eclipse.jface.text/src/org/eclipse/jface/internal/text/codemining/CodeMiningLineHeaderAnnotation.java

@@ -290,4 +290,8 @@ public Consumer<MouseEvent> getAction(MouseEvent e) {
 	public boolean isInVisibleLines() {
 		return super.isInVisibleLines();
 	}
+
+	public List<ICodeMining> getMinings() {
+		return fMinings;
+	}
 }

bundles/org.eclipse.jface.text/src/org/eclipse/jface/internal/text/codemining/CodeMiningManager.java

@@ -297,7 +297,7 @@ private void renderCodeMinings(Map<Position, List<ICodeMining>> groups, ISourceV
 			CodeMiningMode mode= CodeMiningMode.createFor(minings);
 
 			// Try to find existing annotation
-			AbstractInlinedAnnotation ann= fInlinedAnnotationSupport.findExistingAnnotation(pos);
+			AbstractInlinedAnnotation ann= fInlinedAnnotationSupport.findExistingAnnotation(pos, minings);
 			if (ann == null || !mode.annotationType.isInstance(ann)) {
 				// The annotation doesn't exists or has wrong type => create a new one.
 				boolean afterPosition= false;

bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/source/inlined/InlinedAnnotationSupport.java

@@ -43,6 +43,7 @@
 import org.eclipse.core.runtime.Assert;
 
 import org.eclipse.jface.internal.text.codemining.CodeMiningLineContentAnnotation;
+import org.eclipse.jface.internal.text.codemining.CodeMiningLineHeaderAnnotation;
 
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.DocumentEvent;
@@ -58,6 +59,7 @@
 import org.eclipse.jface.text.Position;
 import org.eclipse.jface.text.Region;
 import org.eclipse.jface.text.TextPresentation;
+import org.eclipse.jface.text.codemining.ICodeMining;
 import org.eclipse.jface.text.source.Annotation;
 import org.eclipse.jface.text.source.AnnotationPainter;
 import org.eclipse.jface.text.source.IAnnotationModel;
@@ -483,8 +485,15 @@ public void updateAnnotations(Set<AbstractInlinedAnnotation> annotations) {
 	 * @return the existing codemining annotation with the given position information and null
 	 *         otherwise.
 	 */
-	@SuppressWarnings("unchecked")
 	public <T extends AbstractInlinedAnnotation> T findExistingAnnotation(Position pos) {
+		return findExistingAnnotation(pos, null);
+	}
+
+	/**
+	 * @since 3.30
+	 */
+	@SuppressWarnings("unchecked")
+	public <T extends AbstractInlinedAnnotation> T findExistingAnnotation(Position pos, List<ICodeMining> minings) {
 		if (fInlinedAnnotations == null) {
 			return null;
 		}
@@ -496,6 +505,22 @@ public <T extends AbstractInlinedAnnotation> T findExistingAnnotation(Position p
 					// Do nothing
 				}
 			}
+			if (minings == null) {
+				continue;
+			}
+			List<ICodeMining> existingMinings= null;
+			if (ann instanceof CodeMiningLineHeaderAnnotation lineHeader) {
+				existingMinings= lineHeader.getMinings();
+			} else if (ann instanceof CodeMiningLineContentAnnotation lineContent) {
+				existingMinings= lineContent.getMinings();
+			}
+			if (existingMinings != null && existingMinings.equals(minings) && ann.getPosition() != null && !ann.getPosition().isDeleted()) {
+				try {
+					return (T) ann;
+				} catch (ClassCastException e) {
+					// Do nothing
+				}
+			}
 		}
 		return null;
 	}