Prevents adding duplicate filenames

Author: Robert Roos

src/tctools/patch_plc/patch_plc_class.py

@@ -18,10 +18,12 @@ class FileItems:
     files: set[Path] = field(default_factory=set)
 
     def add(self, other: "FileItems"):
+        """Merge in another set of files/folders."""
         self.folders |= other.folders
         self.files |= other.files
 
     def subtract(self, other: "FileItems"):
+        """Remove files/folders that occur in another set."""
         self.folders = self.folders.difference(other.folders)
         self.files = self.files.difference(other.files)
 
@@ -178,6 +180,8 @@ def operation_merge(
         """See help info for `merge`."""
         new_sources = FileItems.merge(new_sources.values())
 
+        self.skip_file_duplicates(new_sources, current_sources)
+
         sizes_all = (len(new_sources.folders), len(new_sources.files))
 
         new_sources.subtract(current_sources)
@@ -251,6 +255,8 @@ def operation_reset(self, current_sources: FileItems, new_sources: FileItemsGrou
         to_remove.subtract(to_add)  # Don't remove sources that are real
         to_add.subtract(current_sources)  # Don't add sources that are already known
 
+        self.skip_file_duplicates(to_add, current_sources)
+
         # Empty folders will also be removed, make sure to keep them:
         to_remove.folders = set(
             f for f in to_remove.folders if not (self._project_file.parent / f).exists()
@@ -268,7 +274,7 @@ def operation_reset(self, current_sources: FileItems, new_sources: FileItemsGrou
         )
 
         # Decide what to do next:
-        if not to_remove.is_empty() and to_add.is_empty():
+        if to_remove.is_empty() and to_add.is_empty():
             self.logger.info("No files or folders to change, stopping")
             return 0
 
@@ -312,6 +318,25 @@ def determine_source_folders(self, source_files: Iterable[Path]) -> FileItems:
 
         return sources
 
+    def skip_file_duplicates(
+        self,
+        new_sources: FileItems,
+        current_sources: FileItems,
+    ):
+        """Avoid duplicate file names (regardless of full path).
+
+        ``current_sources`` is modified in-place.
+        """
+        filenames = set(f.name for f in current_sources.files)  # Reduce to just names
+        to_pop = set()
+        for file in new_sources.files:
+            if file.name in filenames:
+                to_pop.add(file)
+                self.logger.warning(f"Refusing to add existing file name: {file}")
+
+        if to_pop:
+            new_sources.files -= to_pop
+
     def get_project_sources(self, tree) -> FileItems:
         """Get all files and folders currently in a PLC project."""
 

tests/test_patch_plc.py

@@ -1,3 +1,4 @@
+import logging
 import shutil
 import subprocess
 import sys
@@ -214,7 +215,7 @@ def test_reset(plc_code):
         assert item not in content_before
 
     # Reset to the entire local directory:
-    code = PatchPlc(str(project), "reset", "-r", str(project.parent)).run()
+    code = PatchPlc(str(project), "reset", "-r", str(plc_dir)).run()
     assert code == 0
 
     content_after = project.read_text()
@@ -226,3 +227,28 @@ def test_reset(plc_code):
     lines_after = content_after.count("\n")
     assert lines_before - (2 * 1) - (3 * 3) + (2 * 1) + (4 * 3) == lines_after
     # Remove 2 folders and 3 files, add 2 folders and 4 files
+
+
+def test_reset_duplicate(plc_code, caplog):
+    plc_dir = plc_code / "TwinCAT Project1" / "MyPlc"
+    project = plc_dir / "MyPlc.plcproj"
+
+    # Create a new file, with a name that's already known:
+    module_folder = plc_dir / "POUs" / "Module"
+    new_file = module_folder / "DUTs" / "MAIN.TcPOU"
+    new_file.write_text("\n")  # Create the file
+
+    content_before = project.read_text()
+
+    with caplog.at_level(logging.WARNING):
+        code = PatchPlc(str(project), "reset", str(module_folder), "-r").run()
+
+    assert code == 0
+
+    assert len(caplog.records) == 1
+    assert (
+        caplog.records[0].message
+        == "Refusing to add existing file name: POUs\Module\DUTs\MAIN.TcPOU"
+    )
+
+    assert content_before == project.read_text()  # The project should not be changed