Kludge: don't duplicate plot instructions to tikz

Fixes nschloe#609

src/tikzplotlib/_path.py

@@ -249,7 +249,11 @@ def draw_pathcollection(data, obj):
     if legend_text is None and has_legend(obj.axes):
         draw_options.append("forget plot")
 
+    # track content that's been seen so we can de-duplicate (this is a bit of a kludge)
+    code_seen = set()
+    table_map = {}
     for path in obj.get_paths():
+        cur_content = []
         if is_contour:
             dd = path.vertices
             # https://matplotlib.org/stable/api/path_api.html
@@ -289,34 +293,41 @@ def draw_pathcollection(data, obj):
         len_row = sum(len(item) for item in draw_options)
         j0, j1, j2 = ("", ", ", "") if len_row < 80 else ("\n  ", ",\n  ", "\n")
         do = f" [{j0}{{}}{j2}]".format(j1.join(draw_options)) if draw_options else ""
-        content.append(f"\\addplot{do}\n")
+        cur_content.append(f"\\addplot{do}\n")
 
         if data["externals search path"] is not None:
             esp = data["externals search path"]
             table_options.append(f"search path={{{esp}}}")
 
         if len(table_options) > 0:
             table_options_str = ", ".join(table_options)
-            content.append(f"table [{table_options_str}]{{")
+            cur_content.append(f"table [{table_options_str}]{{")
         else:
-            content.append("table{")
+            cur_content.append("table{")
 
         plot_table = []
         plot_table.append("  ".join(labels) + "\n")
         for row in dd_strings:
             plot_table.append(" ".join(row) + "\n")
 
         if data["externalize tables"]:
-            filepath, rel_filepath = _files.new_filepath(data, "table", ".dat")
-            with open(filepath, "w") as f:
-                # No encoding handling required: plot_table is only ASCII
-                f.write("".join(plot_table))
-            content.append(str(rel_filepath))
+            plot_table_str = "".join(plot_table)
+            if plot_table_str not in table_map:
+                filepath, rel_filepath = _files.new_filepath(data, "table", ".dat")
+                with open(filepath, "w") as f:
+                    # No encoding handling required: plot_table is only ASCII
+                    f.write("".join(plot_table))
+                table_map[plot_table_str] = str(rel_filepath)
+            cur_content.append(table_map[plot_table_str])
         else:
-            content.append("%\n")
-            content.extend(plot_table)
-
-        content.append("};\n")
+            cur_content.append("%\n")
+            cur_content.extend(plot_table)
+
+        cur_content.append("};\n")
+        # very dumb kludge: skip duplicates
+        if tuple(cur_content) not in code_seen:
+            content.extend(cur_content)
+            code_seen.add(tuple(cur_content))
 
     if legend_text is not None:
         content.append(f"\\addlegendentry{{{_common_texification(legend_text)}}}\n")