snap-tool info prints out the base

debian/changelog

@@ -3,6 +3,8 @@ livecd-rootfs (2.573) UNRELEASED; urgency=medium
   * When the "snap-tool" script encounters a core snap it will switch to
     the "stable" channel if the channel was set to "stable/ubuntu-X.X". This
     ensures that core snaps always come from one canonical source.
+  * Running `snap-tool info <snap_name>` will now also print out the base of
+    the snap.
 
  -- Tobias Koch <tobias.koch@canonical.com>  Wed, 20 Mar 2019 14:33:34 +0100
 

snap-tool

@@ -151,8 +151,7 @@ class Snap:
         if self._details and not cohort_create:
             return self._details
 
-        if re.match(r"^core\d*$", self._name) and \
+        if self.is_core_snap() and self._channel.startswith("stable/ubuntu-"):
-                self._channel.startswith("stable/ubuntu-"):
             sys.stderr.write(
                 "WARNING: switching channel from '{}' to 'stable' for '{}' "
                 "snap.\n".format(self._channel, self._name)
@@ -170,7 +169,22 @@ class Snap:
                     "name":         self._name,
                     "channel":      self._channel,
                 }
-            ]
+            ],
+            "fields": [
+                "base",
+                "created-at",
+                "download",
+                "license",
+                "name",
+                "prices",
+                "publisher",
+                "revision",
+                "snap-id",
+                "summary",
+                "title",
+                "type",
+                "version",
+            ],
         }
 
         # These are mutually exclusive.
@@ -189,6 +203,12 @@ class Snap:
 
         snap_data = response_dict["results"][0]
 
+        # Have "base" initialized to something meaningful.
+        if self.is_core_snap():
+            snap_data["snap"]["base"] = ""
+        elif snap_data["snap"].get("base") is None:
+            snap_data["snap"]["base"] = "core"
+
         # Copy the key into the snap details.
         if "cohort-key" in snap_data:
             snap_data["snap"]["cohort-key"] = snap_data["cohort-key"]
@@ -266,6 +286,9 @@ class Snap:
         self._assertions["account-key"] = data
         return data
 
+    def is_core_snap(self):
+        return re.match(r"^core\d*$", self._name) != None
+
     def _do_assertion_request(self, path):
         url = self._assertion_url + path
 
@@ -381,6 +404,7 @@ class SnapCli:
             name:      {}
             summary:   {}
             arch:      {}
+            base:      {}
             channel:   {}
             publisher: {}
             license:   {}
@@ -390,6 +414,7 @@ class SnapCli:
                 snap_name,
                 info.get("summary", ""),
                 snap._arch,
+                info.get("base"),
                 snap._channel,
                 info.get("publisher", {}).get("display-name", ""),
                 info.get("license", ""),