From 8b89ca7f3a7d7a8cb8b270a6d58170673d2d782b Mon Sep 17 00:00:00 2001
From: Lucas Cimon <925560+Lucas-C@users.noreply.github.com>
Date: Fri, 13 Jan 2023 18:19:58 +0100
Subject: [PATCH] Raising an error when trying to add a link with no page
 number

---
 fpdf/fpdf.py                  | 4 ++++
 test/image/test_load_image.py | 2 +-
 test/image/test_oversized.py  | 2 +-
 test/test_links.py            | 9 +++++++++
 4 files changed, 15 insertions(+), 2 deletions(-)
 mode change 100755 => 100644 test/test_links.py

diff --git a/fpdf/fpdf.py b/fpdf/fpdf.py
index c7711bd49..95d765510 100644
--- a/fpdf/fpdf.py
+++ b/fpdf/fpdf.py
@@ -2058,6 +2058,10 @@ def link(self, x, y, w, h, link, alt_text=None, border_width=0):
                     link in self.links
                 ), f"Link with an invalid index: {link} (doc #links={len(self.links)})"
                 dest = self.links[link]
+                if not dest.page_number:
+                    raise ValueError(
+                        f"Cannot insert link {link} with no page number assigned"
+                    )
         link_annot = AnnotationDict(
             "Link",
             x=x * self.k,
diff --git a/test/image/test_load_image.py b/test/image/test_load_image.py
index 9e159dacf..88604d8ac 100644
--- a/test/image/test_load_image.py
+++ b/test/image/test_load_image.py
@@ -42,7 +42,7 @@ def test_load_invalid_base64_data():
 
 
 # ensure memory usage does not get too high - this value depends on Python version:
-@memunit.assert_lt_mb(141)
+@memunit.assert_lt_mb(145)
 def test_share_images_cache(tmp_path):
     images_cache = {}
 
diff --git a/test/image/test_oversized.py b/test/image/test_oversized.py
index 5b2e8d197..3a82eac61 100644
--- a/test/image/test_oversized.py
+++ b/test/image/test_oversized.py
@@ -9,7 +9,7 @@
 
 HERE = Path(__file__).resolve().parent
 IMAGE_PATH = HERE / "png_images/6c853ed9dacd5716bc54eb59cec30889.png"
-MAX_MEMORY_MB = 143  # memory usage depends on Python version
+MAX_MEMORY_MB = 145  # memory usage depends on Python version
 
 
 def test_oversized_images_warn(caplog):
diff --git a/test/test_links.py b/test/test_links.py
old mode 100755
new mode 100644
index c401eafe4..6e77a28d7
--- a/test/test_links.py
+++ b/test/test_links.py
@@ -160,3 +160,12 @@ def test_inserting_link_to_non_exising_page():
     )
     with pytest.raises(ValueError):
         pdf.output()
+
+
+def test_inserting_link_with_no_page_number():
+    pdf = FPDF()
+    link = pdf.add_link()
+    pdf.add_page()
+    pdf.set_font("helvetica", size=12)
+    with pytest.raises(ValueError):
+        pdf.cell(txt="Page 1", link=link)