Better Diagnostic for LaTeX errors

copienator/utils.py

@@ -177,21 +177,23 @@ def compile_to_pdf(text, output_pdf_path):
                     text=True,
                     check=False)
 
+            generated_pdf = os.path.join(temp_dir, pdf_filename)
+            pdf_generated = os.path.exists(generated_pdf)
+            if pdf_generated:
+                shutil.move(generated_pdf, output_pdf_path)
+
             if result.returncode != 0:
                 error_lines = [
                     line.strip() for line in result.stdout.splitlines()
                     if line.lstrip().startswith("!")
                 ]
                 detail = f": {error_lines[0]}" if error_lines else ""
+                pdf_status = "a PDF was generated" if pdf_generated else "no PDF was generated"
                 print(
-                    f"Warning: LaTeX compilation failed for {output_pdf_path} "
-                    f"(exit code {result.returncode}){detail}"
+                    f"Warning: LaTeX compilation reported errors for {output_pdf_path} "
+                    f"(exit code {result.returncode}; {pdf_status}){detail}"
                 )
-
-            generated_pdf = os.path.join(temp_dir, pdf_filename)
-            if os.path.exists(generated_pdf):
-                shutil.move(generated_pdf, output_pdf_path)
-            else:
+            elif not pdf_generated:
                 print(f"Warning: LaTeX compilation produced no PDF for {output_pdf_path}")
         except Exception as e:
             print(f"Compilation error for {output_pdf_path}: {e}")

tests/test_utils_compile.py

@@ -27,9 +27,26 @@ class CompileToPdfTests(unittest.TestCase):
                 utils.compile_to_pdf("broken", output)
 
             self.assertEqual(output.read_bytes(), b"partial")
-            self.assertIn("Warning: LaTeX compilation failed", console.getvalue())
+            self.assertIn("Warning: LaTeX compilation reported errors", console.getvalue())
+            self.assertIn("a PDF was generated", console.getvalue())
             self.assertIn("missing \\item", console.getvalue())
 
+    def test_says_no_pdf_was_generated_when_latex_fails(self):
+        with tempfile.TemporaryDirectory() as temporary:
+            output = Path(temporary) / "result.pdf"
+            result = subprocess.CompletedProcess(
+                args=[], returncode=1, stdout="! Undefined control sequence.\n"
+            )
+
+            console = io.StringIO()
+            with patch.object(utils.subprocess, "run", return_value=result), \
+                    contextlib.redirect_stdout(console):
+                utils.compile_to_pdf("broken", output)
+
+            self.assertFalse(output.exists())
+            self.assertIn("no PDF was generated", console.getvalue())
+            self.assertIn("Undefined control sequence", console.getvalue())
+
     def test_warns_when_no_pdf_is_produced(self):
         with tempfile.TemporaryDirectory() as temporary:
             output = Path(temporary) / "result.pdf"