sources: support symlinks in deb sources

HACKING.md

@@ -58,7 +58,7 @@ If you don't have python3 installed, you can use the one from the archives:
 
 Install the needed dependencies.
 
-    sudo apt install build-essential python3-dev libapt-pkg-dev libsodium-dev gcc libffi-dev libarchive13 squashfs-tools xdelta3
+    sudo apt install build-essential python3-dev python3-debian libapt-pkg-dev libsodium-dev gcc libffi-dev libarchive13 squashfs-tools xdelta3
 
 If installing to `PYTHONHOME` run:
 

debian/control

@@ -8,6 +8,7 @@ Build-Depends: bash-completion,
                pkg-config,
                python3 (>= 3.4),
                python3-apt,
+               python3-debian,
                python3-docopt,
                python3-fixtures,
                python3-jsonschema,
@@ -38,6 +39,7 @@ Standards-Version: 3.9.8
 Package: snapcraft
 Architecture: all
 Depends: python3-apt,
+         python3-debian,
          python3-docopt,
          python3-jsonschema,
          python3-libarchive-c,

integration_tests/snaps/simple-deb/snapcraft.yaml

@@ -13,3 +13,6 @@ parts:
     plugin: dump
     source: small_0.1-1.deb
 
+  deb-with-symlink:
+    plugin: dump
+    source: symlink_1.0.deb

integration_tests/test_deb_source.py

@@ -16,7 +16,10 @@
 
 import os
 
-from testtools.matchers import FileExists
+from testtools.matchers import (
+    Equals,
+    FileExists
+)
 
 import integration_tests
 
@@ -25,11 +28,23 @@ class DebSourceTestCase(integration_tests.TestCase):
 
     def test_stage_deb(self):
         project_dir = self.copy_project_to_tmp('simple-deb')
-        self.run_snapcraft('stage', project_dir)
+        self.run_snapcraft(['stage', 'deb'], project_dir)
 
         self.assertThat(
             os.path.join(project_dir, 'stage', 'bin', 'hello'),
             FileExists())
         self.assertThat(
             os.path.join(project_dir, 'stage', 'usr', 'bin', 'world'),
             FileExists())
+
+    # Regression test for LP: #1634813
+    def test_stage_deb_with_symlink(self):
+        project_dir = self.copy_project_to_tmp('simple-deb')
+        self.run_snapcraft(['stage', 'deb-with-symlink'], project_dir)
+
+        target = os.path.join(project_dir, 'stage', 'target')
+        symlink = os.path.join(project_dir, 'stage', 'symlink')
+        self.assertThat(target, FileExists())
+        self.assertThat(symlink, FileExists())
+        self.assertTrue(os.path.islink(symlink))
+        self.assertThat(os.readlink(symlink), Equals('target'))

requirements.txt

@@ -16,3 +16,5 @@ pymacaroons==0.9.2
 pymacaroons-pynacl==0.9.3
 simplejson==3.8.2
 tabulate==0.7.5
+python-debian==0.1.28
+chardet==2.3.0

snapcraft/internal/sources/_deb.py

@@ -14,7 +14,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-import apt_inst
+import debian.debfile
 import os
 import shutil
 import tempfile
@@ -49,8 +49,8 @@ def provision(self, dst, clean_target=True, keep_deb=False):
             os.makedirs(dst)
             shutil.move(tmp_deb, deb_file)
 
-        deb = apt_inst.DebFile(deb_file)
-        deb.data.extractall(dst)
+        deb = debian.debfile.DebFile(deb_file)
+        deb.data.tgz().extractall(dst)
 
         if not keep_deb:
             os.remove(deb_file)

snapcraft/tests/sources/test_deb.py

@@ -27,7 +27,7 @@ class TestDeb(tests.FakeFileHTTPServerBasedTestCase):
     def setUp(self):
         super().setUp()
 
-        patcher = mock.patch('apt_inst.DebFile')
+        patcher = mock.patch('debian.debfile.DebFile')
         self.mock_deb = patcher.start()
         self.addCleanup(patcher.stop)