Update objects when path changes for MultiFileSelector and FileSelector

examples/user_guide/Parameter_Types.ipynb

@@ -745,9 +745,11 @@
     "\n",
     "A `param.ListSelector` works just the same as a regular Selector, but the value is a _list_ of valid objects from the available objects, rather than just one. Each item in the list is checked against the `objects`, and thus the current value is thus a _subset_ of the `objects`, rather than just one of the objects.\n",
     "\n",
-    "A `param.FileSelector` works like a regular Selector with the value being a filename and the `objects` being computed from files on a file system. The files are specified as a `path` [glob](https://docs.python.org/3/library/glob.html), and all filenames matching the glob are valid `objects` for the parameter.\n",
+    "A `param.FileSelector` works like a Selector with the value being a filename and the `objects` being computed from files on a file system. The files are specified as a `path` [glob](https://docs.python.org/3/library/glob.html), and all filenames matching the glob are valid `objects` for the parameter. The default value is *None* unless specified.\n",
     "\n",
-    "A `param.MultiFileSelector` is the analog of ListSelector but for files, i.e., again supporting a path glob but allowing the user to select a list of filenames rather than a single filename. The default value in this case is _all_ of the matched files, not just the first one."
+    "A `param.MultiFileSelector` is the analog of ListSelector but for files, i.e., again supporting a path glob but allowing the user to select a list of filenames rather than a single filename. The default value in this case is _all_ of the matched files, not just the first one. The default value is `None` unless specified.\n",
+    "\n",
+    "Both `param.FileSelector` and `param.MultiFileSelector` have an `update` method that sets `objects` with the results of a *glob* on the current `path`. This can be useful when the filesystem has changed. When `update` is called the default value of `param.FileSelector` is set to the first path of `objects` and the default value of `param.MultiFileSelector` is set equal to `objects`."
    ]
   },
   {

param/__init__.py

@@ -1275,7 +1275,7 @@ def _validate(self, val):
                     limiter = ', ...]'
                     break
             items = '[' + ', '.join(items) + limiter
-            raise ValueError("%s not in parameter%s's list of possible objects, "
+            raise ValueError("%r not in parameter%s's list of possible objects, "
                              "valid options include %s" % (val, attrib_name, items))
 
     def _ensure_value_is_in_objects(self,val):
@@ -1827,11 +1827,6 @@ def __init__(self, default=None, path="", **kwargs):
         super(FileSelector, self).__init__(default=default, objects=self.objects,
                                            empty_default=True, **kwargs)
 
-    def _on_set(self, attribute, old, new):
-        super(FileSelector, self)._on_set(attribute, new, old)
-        if attribute == 'path':
-            self.update()
-
     def update(self):
         self.objects = sorted(glob.glob(self.path))
         if self.default in self.objects:
@@ -1879,11 +1874,6 @@ def __init__(self, default=None, path="", **kwargs):
         self.update()
         super(MultiFileSelector, self).__init__(default=default, objects=self.objects, **kwargs)
 
-    def _on_set(self, attribute, old, new):
-        super(MultiFileSelector, self)._on_set(attribute, new, old)
-        if attribute == 'path':
-            self.update()
-
     def update(self):
         self.objects = sorted(glob.glob(self.path))
         if self.default and all([o in self.objects for o in self.default]):

tests/API1/testfileselector.py

@@ -0,0 +1,106 @@
+import os
+import shutil
+import tempfile
+
+import param
+
+from . import API1TestCase
+
+
+class TestFileSelectorParameters(API1TestCase):
+
+    def setUp(self):
+        super(TestFileSelectorParameters, self).setUp()
+
+        tmpdir1 = tempfile.mkdtemp()
+        fa = os.path.join(tmpdir1, 'a.txt')
+        fb = os.path.join(tmpdir1, 'b.txt')
+        glob1 = os.path.join(tmpdir1, '*')
+        open(fa, 'w').close()
+        open(fb, 'w').close()
+        tmpdir2 = tempfile.mkdtemp()
+        fc = os.path.join(tmpdir2, 'c.txt')
+        fd = os.path.join(tmpdir2, 'd.txt')
+        glob2 = os.path.join(tmpdir2, '*')
+        open(fc, 'w').close()
+        open(fd, 'w').close()
+
+        self.tmpdir1 = tmpdir1
+        self.tmpdir2 = tmpdir2
+        self.fa = fa
+        self.fb = fb
+        self.fc = fc
+        self.fd = fd
+        self.glob1 = glob1
+        self.glob2 = glob2
+
+        class P(param.Parameterized):
+            a = param.FileSelector(path=glob1)
+            b = param.FileSelector(default=fa, path=glob1)
+
+        self.P = P
+
+    def tearDown(self):
+        shutil.rmtree(self.tmpdir1)
+        shutil.rmtree(self.tmpdir2)
+
+    def test_default_is_None(self):
+        p = self.P()
+        assert p.a is None
+        assert p.param.a.default is None
+
+    def test_default_is_honored(self):
+        p = self.P()
+        assert p.b == self.fa
+        assert p.param.b.default in [self.fa, self.fb]
+
+    def test_allow_default_None(self):
+        class P(param.Parameterized):
+            a = param.FileSelector(default=None)
+
+    def test_default_not_in_glob(self):
+        with self.assertRaises(ValueError):
+            class P(param.Parameterized):
+                a = param.FileSelector(default='not/in/glob', path=self.glob1)
+
+    def test_objects_auto_set(self):
+        p = self.P()
+        assert p.param.a.objects == [self.fa, self.fb]
+
+    def test_set_object_constructor(self):
+        p = self.P(a=self.fb)
+        assert p.a == self.fb
+
+    def test_set_object_outside_bounds(self):
+        p = self.P()
+        with self.assertRaises(ValueError):
+            p.a = '/not/in/glob'
+
+    def test_set_path_and_update(self):
+        p = self.P()
+        p.param.b.path = self.glob2
+        p.param.b.update()
+        assert p.param.b.objects == [self.fc, self.fd]
+        assert p.param.b.default in [self.fc, self.fd]
+        # Default updated but not the value itself
+        assert p.b == self.fa
+
+    def test_get_range(self):
+        p = self.P()
+        r = p.param.a.get_range()
+        assert r['a.txt'] == self.fa
+        assert r['b.txt'] == self.fb
+        p.param.a.path = self.glob2
+        p.param.a.update()
+        r = p.param.a.get_range()
+        assert r['c.txt'] == self.fc
+        assert r['d.txt'] == self.fd
+
+    def test_update_file_removed(self):
+        p = self.P()
+        assert p.param.b.objects == [self.fa, self.fb]
+        assert p.param.b.default in [self.fa, self.fb]
+        os.remove(self.fa)
+        p.param.b.update()
+        assert p.param.b.objects == [self.fb]
+        assert p.param.b.default == self.fb

tests/API1/testmultifileselector.py

@@ -0,0 +1,110 @@
+import os
+import shutil
+import tempfile
+
+import param
+
+from . import API1TestCase
+
+
+class TestMultiFileSelectorParameters(API1TestCase):
+
+    def setUp(self):
+        super(TestMultiFileSelectorParameters, self).setUp()
+
+        tmpdir1 = tempfile.mkdtemp()
+        fa = os.path.join(tmpdir1, 'a.txt')
+        fb = os.path.join(tmpdir1, 'b.txt')
+        glob1 = os.path.join(tmpdir1, '*')
+        open(fa, 'w').close()
+        open(fb, 'w').close()
+        tmpdir2 = tempfile.mkdtemp()
+        fc = os.path.join(tmpdir2, 'c.txt')
+        fd = os.path.join(tmpdir2, 'd.txt')
+        glob2 = os.path.join(tmpdir2, '*')
+        open(fc, 'w').close()
+        open(fd, 'w').close()
+
+        self.tmpdir1 = tmpdir1
+        self.tmpdir2 = tmpdir2
+        self.fa = fa
+        self.fb = fb
+        self.fc = fc
+        self.fd = fd
+        self.glob1 = glob1
+        self.glob2 = glob2
+
+        class P(param.Parameterized):
+            a = param.MultiFileSelector(path=glob1)
+            b = param.MultiFileSelector(default=[fa], path=glob1)
+
+        self.P = P
+
+    def tearDown(self):
+        shutil.rmtree(self.tmpdir1)
+        shutil.rmtree(self.tmpdir2)
+
+    def test_default_is_None(self):
+        p = self.P()
+        assert p.a is None
+        assert p.param.a.default is None
+
+    def test_default_is_honored(self):
+        p = self.P()
+        assert p.b == [self.fa]
+        assert p.param.b.default ==[self.fa]
+
+    def test_allow_default_None(self):
+        class P(param.Parameterized):
+            a = param.FileSelector(default=None)
+
+    def test_objects_auto_set(self):
+        p = self.P()
+        assert p.param.a.objects == [self.fa, self.fb]
+
+    def test_default_not_in_glob(self):
+        with self.assertRaises(ValueError):
+            class P(param.Parameterized):
+                a = param.FileSelector(default=['not/in/glob'], path=self.glob1)
+
+    def test_objects_auto_set(self):
+        p = self.P()
+        assert sorted(p.param.a.objects) == sorted([self.fa, self.fb])
+
+    def test_set_object_constructor(self):
+        p = self.P(a=[self.fb])
+        assert p.a == [self.fb]
+
+    def test_set_object_outside_bounds(self):
+        p = self.P()
+        with self.assertRaises(ValueError):
+            p.a = ['/not/in/glob']
+
+    def test_set_path_and_update(self):
+        p = self.P()
+        p.param.b.path = self.glob2
+        p.param.b.update()
+        assert sorted(p.param.b.objects) == sorted([self.fc, self.fd])
+        assert sorted(p.param.b.default) == sorted([self.fc, self.fd])
+        # Default updated but not the value itself
+        assert p.b == [self.fa]
+
+    def test_get_range(self):
+        p = self.P()
+        r = p.param.a.get_range()
+        assert r['a.txt'] == self.fa
+        assert r['b.txt'] == self.fb
+        p.param.a.path = self.glob2
+        p.param.a.update()
+        r = p.param.a.get_range()
+        assert r['c.txt'] == self.fc
+        assert r['d.txt'] == self.fd
+
+    def test_update_file_removed(self):
+        p = self.P()
+        assert p.param.b.objects == [self.fa, self.fb]
+        assert p.param.b.default == [self.fa]
+        os.remove(self.fa)
+        p.param.b.update()
+        assert p.param.b.objects == [self.fb]
+        assert p.param.b.default == [self.fb]