From 222cf6c2dd89d9c70565f170fb57079b77c21e27 Mon Sep 17 00:00:00 2001
From: Horst Rutter <hhrutter@gmail.com>
Date: Thu, 1 Feb 2024 11:02:58 +0100
Subject: [PATCH] Fix #796

---
 pkg/pdfcpu/annotation.go          | 10 +++++++++-
 pkg/pdfcpu/validate/structTree.go |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/pkg/pdfcpu/annotation.go b/pkg/pdfcpu/annotation.go
index cd25325c9..05b2aaab5 100644
--- a/pkg/pdfcpu/annotation.go
+++ b/pkg/pdfcpu/annotation.go
@@ -494,7 +494,7 @@ func removeAllAnnotations(
 			return false, err
 		}
 		objNr := ir.ObjectNumber.Value()
-		if err := ctx.DeleteObject(ir); err != nil {
+		if err = ctx.FreeObject(objNr); err != nil {
 			return false, err
 		}
 		if incr {
@@ -502,6 +502,7 @@ func removeAllAnnotations(
 			ctx.Write.IncrementWithObjNr(objNr)
 		}
 	}
+
 	annots, _ := obj.(types.Array)
 
 	for _, o := range annots {
@@ -930,5 +931,12 @@ func RemoveAnnotations(ctx *model.Context, selectedPages types.IntSet, idsAndTyp
 		}
 	}
 
+	if removeAll {
+		// Hacky, actually we only want to remove struct tree elements using removed annotations
+		// but this is most probably what we want anyway.
+		root, _ := ctx.Catalog()
+		root.Delete("StructTreeRoot")
+	}
+
 	return removed, nil
 }
diff --git a/pkg/pdfcpu/validate/structTree.go b/pkg/pdfcpu/validate/structTree.go
index febd3c8b9..a3a69b589 100644
--- a/pkg/pdfcpu/validate/structTree.go
+++ b/pkg/pdfcpu/validate/structTree.go
@@ -90,7 +90,7 @@ func validateObjectReferenceDict(xRefTable *model.XRefTable, d types.Dict) error
 	}
 
 	if obj == nil {
-		return errors.New("pdfcpu: validateObjectReferenceDict: missing required entry \"Obj\"")
+		return errors.Errorf("pdfcpu: validateObjectReferenceDict: missing obj#%s", ir.ObjectNumber)
 	}
 
 	return nil