Stop using pkg_resources

pkg_resources is deprecated and we're supposed to use
importlib.resources instead. Unfortunately it's very awkward
to use because it wants to support being able to read from
possibly compressed archives or other Python package distribution
formats.

Since our distribution mechanism is Debian packages, we can avoid
all of this entirely and just read the files off disk like any
other file.

Take the opportunity to simplify font loading: instead of hardcoding
each font, just load every TTF in the fonts/ directory by using a
recursive glob.

And then drop some tests that don't test anything useful

Fixes #1672.
Fixes #1836.

client/securedrop_client/gui/auth/dialog.py

@@ -18,8 +18,8 @@
 """
 import logging
 from gettext import gettext as _
+from pathlib import Path
 
-from pkg_resources import resource_string
 from PyQt5.QtCore import QSize, Qt
 from PyQt5.QtGui import QBrush, QPalette
 from PyQt5.QtWidgets import (
@@ -82,8 +82,8 @@ def __init__(self, parent: QWidget) -> None:
         form = QWidget()
 
         form.setObjectName("LoginDialog_form")
-        styles = resource_string(__name__, "dialog.css").decode("utf-8")
-        self.setStyleSheet(styles)
+        css = Path(__file__).parent / "dialog.css"
+        self.setStyleSheet(css.read_text())
 
         form_layout = QVBoxLayout()
         form.setLayout(form_layout)

client/securedrop_client/gui/auth/sign_in/button.py

@@ -17,8 +17,8 @@
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 from gettext import gettext as _
+from pathlib import Path
 
-from pkg_resources import resource_string
 from PyQt5.QtCore import Qt
 from PyQt5.QtGui import QColor, QCursor
 from PyQt5.QtWidgets import QGraphicsDropShadowEffect, QPushButton
@@ -35,8 +35,8 @@ def __init__(self) -> None:
 
         # Set css id
         self.setObjectName("SignInButton")
-        styles = resource_string(__name__, "button.css").decode("utf-8")
-        self.setStyleSheet(styles)
+        css = Path(__file__).parent / "button.css"
+        self.setStyleSheet(css.read_text())
 
         self.setFixedHeight(40)
         self.setFixedWidth(140)

client/securedrop_client/gui/auth/sign_in/error_bar.py

@@ -16,7 +16,8 @@
 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
-from pkg_resources import resource_string
+from pathlib import Path
+
 from PyQt5.QtCore import QSize
 from PyQt5.QtWidgets import QHBoxLayout, QWidget
 
@@ -32,8 +33,8 @@ def __init__(self) -> None:
         super().__init__()
 
         self.setObjectName("LoginErrorBar")
-        styles = resource_string(__name__, "error_bar.css").decode("utf-8")
-        self.setStyleSheet(styles)
+        css = Path(__file__).parent / "error_bar.css"
+        self.setStyleSheet(css.read_text())
 
         # Set layout
         layout = QHBoxLayout(self)

client/securedrop_client/gui/base/checkbox.py

@@ -6,22 +6,22 @@
 Present in the Sign-in and Export Dialog.
 """
 from gettext import gettext as _
+from pathlib import Path
 
-from pkg_resources import resource_string
 from PyQt5.QtCore import Qt, pyqtSignal
 from PyQt5.QtGui import QCursor, QFont, QMouseEvent
 from PyQt5.QtWidgets import QCheckBox, QFrame, QHBoxLayout, QLabel, QWidget
 
 
 class SDCheckBox(QWidget):
     clicked = pyqtSignal()
-    CHECKBOX_CSS = resource_string(__name__, "checkbox.css").decode("utf-8")
     PASSPHRASE_LABEL_SPACING = 1
 
     def __init__(self) -> None:
         super().__init__()
         self.setObjectName("ShowPassphrase_widget")
-        self.setStyleSheet(self.CHECKBOX_CSS)
+        css = Path(__file__).parent / "checkbox.css"
+        self.setStyleSheet(css.read_text())
 
         font = QFont()
         font.setLetterSpacing(QFont.AbsoluteSpacing, self.PASSPHRASE_LABEL_SPACING)

client/securedrop_client/gui/base/dialogs.py

@@ -17,8 +17,8 @@
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 from gettext import gettext as _
+from pathlib import Path
 
-from pkg_resources import resource_string
 from PyQt5.QtCore import QSize, Qt
 from PyQt5.QtGui import QIcon, QKeyEvent, QPixmap
 from PyQt5.QtWidgets import (
@@ -36,10 +36,13 @@
 from securedrop_client.resources import load_movie
 
 
+def load_css(name: str) -> str:
+    return (Path(__file__).parent / name).read_text()
+
+
 class ModalDialog(QDialog):
-    DIALOG_CSS = resource_string(__name__, "dialogs.css").decode("utf-8")
-    BUTTON_CSS = resource_string(__name__, "dialog_button.css").decode("utf-8")
-    ERROR_DETAILS_CSS = resource_string(__name__, "dialog_message.css").decode("utf-8")
+    BUTTON_CSS = load_css("dialog_button.css")
+    ERROR_DETAILS_CSS = load_css("dialog_message.css")
 
     MARGIN = 40
     NO_MARGIN = 0
@@ -48,7 +51,7 @@ def __init__(self, show_header: bool = True, dangerous: bool = False) -> None:
         parent = QApplication.activeWindow()
         super().__init__(parent)
         self.setObjectName("ModalDialog")
-        self.setStyleSheet(self.DIALOG_CSS)
+        self.setStyleSheet(load_css("dialogs.css"))
         self.setModal(True)
 
         self.show_header = show_header

client/securedrop_client/gui/conversation/export/file_dialog.py

@@ -2,9 +2,9 @@
 A dialog that allows journalists to export sensitive files to a USB drive.
 """
 from gettext import gettext as _
+from pathlib import Path
 from typing import Optional
 
-from pkg_resources import resource_string
 from PyQt5.QtCore import QSize, Qt, pyqtSlot
 from PyQt5.QtGui import QColor, QFont
 from PyQt5.QtWidgets import QGraphicsDropShadowEffect, QLineEdit, QVBoxLayout, QWidget
@@ -17,15 +17,14 @@
 
 
 class FileDialog(ModalDialog):
-    DIALOG_CSS = resource_string(__name__, "dialog.css").decode("utf-8")
-
     PASSPHRASE_LABEL_SPACING = 0.5
     NO_MARGIN = 0
     FILENAME_WIDTH_PX = 260
 
     def __init__(self, device: Device, file_uuid: str, file_name: str) -> None:
         super().__init__()
-        self.setStyleSheet(self.DIALOG_CSS)
+        css = Path(__file__).parent / "dialog.css"
+        self.setStyleSheet(css.read_text())
 
         self._device = device
         self.file_uuid = file_uuid

client/securedrop_client/gui/main.py

@@ -32,7 +32,7 @@
 from securedrop_client.gui.auth import LoginDialog
 from securedrop_client.gui.widgets import LeftPane, MainView, TopPane
 from securedrop_client.logic import Controller
-from securedrop_client.resources import load_css, load_font, load_icon
+from securedrop_client.resources import load_css, load_all_fonts, load_icon
 
 logger = logging.getLogger(__name__)
 
@@ -59,8 +59,7 @@ def __init__(
           place for details / message contents / forms.
         """
         super().__init__()
-        load_font("Montserrat")
-        load_font("Source_Sans_Pro")
+        load_all_fonts()
         self.setStyleSheet(load_css("sdclient.css"))
         self.setWindowTitle(_("SecureDrop Client {}").format(__version__))
         self.setWindowIcon(load_icon(self.icon))

client/securedrop_client/resources/__init__.py

@@ -17,33 +17,33 @@
 You should have received a copy of the GNU Affero General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
-import os
+from pathlib import Path
 from typing import Optional
 
-from pkg_resources import resource_filename, resource_string
 from PyQt5.QtCore import QDir
 from PyQt5.QtGui import QFontDatabase, QIcon, QMovie, QPixmap
 from PyQt5.QtSvg import QSvgWidget
 
+RESOURCES_DIR = Path(__file__).parent
+
 # Add resource directories to the search path.
-QDir.addSearchPath("images", resource_filename(__name__, "images"))
-QDir.addSearchPath("css", resource_filename(__name__, "css"))
+QDir.addSearchPath("images", str(RESOURCES_DIR / "images"))
+QDir.addSearchPath("css", str(RESOURCES_DIR / "css"))
 
 
-def path(name: str, resource_dir: str = "images/") -> str:
+def path(name: str) -> str:
     """
     Return the filename for the referenced image.
 
     Qt uses unix path conventions.
     """
-    return resource_filename(__name__, resource_dir + name)
+    return str(RESOURCES_DIR / "images" / name)
 
 
-def load_font(font_folder_name: str) -> None:
-    directory = resource_filename(__name__, "fonts/") + font_folder_name
-    for filename in os.listdir(directory):
-        if filename.endswith(".ttf"):
-            QFontDatabase.addApplicationFont(directory + "/" + filename)
+def load_all_fonts() -> None:
+    """Load all the fonts in the fonts/ directory"""
+    for font in (RESOURCES_DIR / "fonts").glob("**/*.ttf"):
+        QFontDatabase.addApplicationFont(str(font.absolute()))
 
 
 def load_icon(
@@ -133,7 +133,7 @@ def load_css(name: str) -> str:
     """
     Return the contents of the referenced CSS file in the resources.
     """
-    return resource_string(__name__, "css/" + name).decode("utf-8")
+    return (RESOURCES_DIR / "css" / name).read_text()
 
 
 def load_movie(name: str) -> QMovie:

client/tests/test_resources.py

@@ -8,16 +8,6 @@
 from tests.helper import app  # noqa: F401
 
 
-def test_path(mocker):
-    """
-    Ensure the resource_filename function is called with the expected args and
-    the path function under test returns its result.
-    """
-    r = mocker.patch("securedrop_client.resources.resource_filename", return_value="bar")
-    assert securedrop_client.resources.path("foo") == "bar"
-    r.assert_called_once_with(securedrop_client.resources.__name__, "images/foo")
-
-
 def test_load_icon():
     """
     Check the load_icon function returns the expected QIcon object.
@@ -51,16 +41,6 @@ def test_load_image():
     assert isinstance(result, QPixmap)
 
 
-def test_load_css(mocker):
-    """
-    Ensure the resource_string function is called with the expected args and
-    the load_css function returns its result.
-    """
-    rs = mocker.patch("securedrop_client.resources.resource_string", return_value=b"foo")
-    assert "foo" == securedrop_client.resources.load_css("foo")
-    rs.assert_called_once_with(securedrop_client.resources.__name__, "css/foo")
-
-
 def test_load_movie():
     """
     Check the load_movie function returns the expected QMovie object.