polymorphic fetch()

diff --git a/pinch.py b/pinch.py
index a90ec3b594e0e51e997017a4af2467b0df8242c9..58f7a3290cc507760303858cd90ba351f118d0e0 100644 (file)
--- a/pinch.py
+++ b/pinch.py
@@ -113,21 +113,6 @@ class TarrableSearchPath(SearchPath, ABC):  # pylint: disable=abstract-method
     old_git_revision: str
     table: Dict[str, ChannelTableEntry]
 
-    def fetch(self, v: Verification, section: str,
-              conf: configparser.SectionProxy) -> str:
-        if 'git_repo' not in conf or 'release_name' not in conf:
-            raise Exception(
-                'Cannot update unpinned channel "%s" (Run "pin" before "update")' %
-                section)
-
-        if 'channel_url' in conf:
-            return fetch_with_nix_prefetch_url(
-                v, conf['tarball_url'], Digest16(
-                    conf['tarball_sha256']))
-
-        ensure_git_rev_available(v, self)
-        return git_get_tarball(v, self)
-
 
 class GitSearchPath(TarrableSearchPath):
     def pin(self, v: Verification, conf: configparser.SectionProxy) -> None:
@@ -139,6 +124,16 @@ class GitSearchPath(TarrableSearchPath):
         conf['release_name'] = git_revision_name(v, self)
         conf['git_revision'] = self.git_revision
 
+    def fetch(self, v: Verification, section: str,
+              conf: configparser.SectionProxy) -> str:
+        if 'git_repo' not in conf or 'release_name' not in conf:
+            raise Exception(
+                'Cannot update unpinned channel "%s" (Run "pin" before "update")' %
+                section)
+
+        ensure_git_rev_available(v, self)
+        return git_get_tarball(v, self)
+
 
 class ChannelSearchPath(TarrableSearchPath):
     def pin(self, v: Verification, conf: configparser.SectionProxy) -> None:
@@ -152,6 +147,19 @@ class ChannelSearchPath(TarrableSearchPath):
         conf['tarball_sha256'] = self.table['nixexprs.tar.xz'].digest
         conf['git_revision'] = self.git_revision
 
+    # Lint TODO: Put tarball_url and tarball_sha256 in ChannelSearchPath
+    # pylint: disable=no-self-use
+    def fetch(self, v: Verification, section: str,
+              conf: configparser.SectionProxy) -> str:
+        if 'git_repo' not in conf or 'release_name' not in conf:
+            raise Exception(
+                'Cannot update unpinned channel "%s" (Run "pin" before "update")' %
+                section)
+
+        return fetch_with_nix_prefetch_url(
+            v, conf['tarball_url'], Digest16(
+                conf['tarball_sha256']))
+
 
 def compare(a: str, b: str) -> Tuple[List[str], List[str], List[str]]: