Warn about existing files when renaming or creating a directory

This slightly improves the situation where one can rename an existing
file but there is still an obvious race. The validation only happens
when one changes the input, if you touch something via for example an
ssh session you will still overwrite the file.

For that we can't use `--no-clobber` as that does not fail with an
informative error.

src/fileActions.jsx

@@ -128,6 +128,7 @@ const CreateDirectoryModal = ({ currentPath }) => {
     const [name, setName] = useState("");
     const [nameError, setNameError] = useState(null);
     const [errorMessage, setErrorMessage] = useState(undefined);
+    const { cwdInfo } = useFilesContext();
     const createDirectory = () => {
         const path = currentPath + name;
         cockpit.spawn(["mkdir", path], { superuser: "try", err: "message" })
@@ -172,7 +173,7 @@ const CreateDirectoryModal = ({ currentPath }) => {
                         <TextInput
                           validated={nameError ? "error" : "default"}
                           value={name}
-                          onChange={(_, val) => setDirectoryName(val, setName, setNameError, setErrorMessage)}
+                          onChange={(_, val) => setDirectoryName(val, setName, setNameError, setErrorMessage, cwdInfo)}
                           id="create-directory-input" autoFocus // eslint-disable-line jsx-a11y/no-autofocus
                         />
                         <FormHelper fieldId="create-directory-input" helperTextInvalid={nameError} />
@@ -185,6 +186,7 @@ const CreateDirectoryModal = ({ currentPath }) => {
 
 const RenameItemModal = ({ path, selected }) => {
     const Dialogs = useDialogs();
+    const { cwdInfo } = useFilesContext();
     const [name, setName] = useState(selected.name);
     const [nameError, setNameError] = useState(null);
     const [errorMessage, setErrorMessage] = useState(undefined);
@@ -241,7 +243,7 @@ const RenameItemModal = ({ path, selected }) => {
                     <FormGroup fieldId="rename-item-input" label={_("New name")}>
                         <TextInput
                           value={name}
-                          onChange={(_, val) => setDirectoryName(val, setName, setNameError, setErrorMessage)}
+                          onChange={(_, val) => setDirectoryName(val, setName, setNameError, setErrorMessage, cwdInfo)}
                           id="rename-item-input"
                         />
                         <FormHelper fieldId="rename-item-input" helperTextInvalid={nameError} />
@@ -436,7 +438,7 @@ const EditPermissionsModal = ({ selected, path }) => {
     );
 };
 
-const setDirectoryName = (val, setName, setNameError, setErrorMessage) => {
+const setDirectoryName = (val, setName, setNameError, setErrorMessage, cwdInfo) => {
     setErrorMessage(undefined);
     setName(val);
 
@@ -446,6 +448,8 @@ const setDirectoryName = (val, setName, setNameError, setErrorMessage) => {
         setNameError(_("Name too long."));
     } else if (val.includes("/")) {
         setNameError(_("Name cannot include a /."));
+    } else if (cwdInfo?.entries[val]) {
+        setNameError(_("File or directory already exists"));
     } else {
         setNameError(null);
     }

test/check-application

@@ -488,9 +488,11 @@ class TestFiles(testlib.MachineCase):
         b.click(".pf-v5-c-modal-box__footer button.pf-m-link")  # cancel
 
         # Creating folder with duplicate name should return an error
-        self.create_directory(b, "newdir")
-        self.wait_modal_inline_alert(b, "mkdir: cannot create directory ‘/home/admin/newdir’: File exists")
-        b.click("div.pf-v5-c-modal-box__close button.pf-v5-c-button")
+        b.click("#dropdown-menu")
+        b.click("#create-item")
+        b.set_input_text("#create-directory-input", "newdir")
+        b.wait_in_text("#create-directory-input-helper", "File or directory already exists")
+        b.click(".pf-v5-c-modal-box__footer button.pf-m-link")  # cancel
 
         # Creating folder with empty name should return an error
         self.create_directory(b, "")
@@ -636,8 +638,11 @@ class TestFiles(testlib.MachineCase):
         """)
         b.wait_visible("[data-item='newfile']")
         b.wait_visible("[data-item='dest']")
-        self.rename_item(b, "newfile", "dest")
-        self.wait_modal_inline_alert(b, "mv: cannot overwrite directory '/home/admin/dest' with non-directory")
+        b.click("[data-item='newfile']")
+        b.click("#dropdown-menu")
+        b.click("#rename-item")
+        b.set_input_text("#rename-item-input", "dest")
+        b.wait_in_text("#rename-item-input-helper", "File or directory already exists")
         b.click("button.pf-m-link:contains('Cancel')")
         b.wait_not_present(".pf-v5-c-modal-box")