Move pin_channel() into ChannelSearchPath.pin()

[pinch] / pinch.py

diff --git a/pinch.py b/pinch.py
index a90ec3b594e0e51e997017a4af2467b0df8242c9..78c6d52a325d70fc6b3d0aa065a744708f93fa95 100644 (file)
--- a/pinch.py
+++ b/pinch.py
@@ -22,8 +22,12 @@ from typing import (
     Dict,
     Iterable,
     List,
+    Mapping,
+    NamedTuple,
     NewType,
     Tuple,
+    Type,
+    Union,
 )
 
 # Use xdg module when it's less painful to have as a dependency
@@ -86,19 +90,38 @@ class ChannelTableEntry(types.SimpleNamespace):
     url: str
 
 
-class SearchPath(types.SimpleNamespace, ABC):
+class AliasPin(NamedTuple):
+    pass
+
+
+class GitPin(NamedTuple):
+    git_revision: str
     release_name: str
 
+
+class ChannelPin(NamedTuple):
+    git_revision: str
+    release_name: str
+    tarball_url: str
+    tarball_sha256: str
+
+
+Pin = Union[AliasPin, GitPin, ChannelPin]
+
+
+class SearchPath(types.SimpleNamespace, ABC):
+
     @abstractmethod
-    def pin(self, v: Verification, conf: configparser.SectionProxy) -> None:
+    def pin(self, v: Verification) -> Pin:
         pass
 
 
 class AliasSearchPath(SearchPath):
     alias_of: str
 
-    def pin(self, v: Verification, conf: configparser.SectionProxy) -> None:
+    def pin(self, v: Verification) -> AliasPin:
         assert not hasattr(self, 'git_repo')
+        return AliasPin()
 
 
 # (This lint-disable is for pylint bug https://github.com/PyCQA/pylint/issues/179
@@ -109,10 +132,20 @@ class TarrableSearchPath(SearchPath, ABC):  # pylint: disable=abstract-method
     forwarded_url: str
     git_ref: str
     git_repo: str
-    git_revision: str
     old_git_revision: str
     table: Dict[str, ChannelTableEntry]
 
+
+class GitSearchPath(TarrableSearchPath):
+    def pin(self, v: Verification) -> GitPin:
+        if hasattr(self, 'git_revision'):
+            self.old_git_revision = self.git_revision
+            del self.git_revision
+
+        git_fetch(v, self)
+        return GitPin(release_name=git_revision_name(v, self),
+                      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:
@@ -120,37 +153,39 @@ class TarrableSearchPath(SearchPath, ABC):  # pylint: disable=abstract-method
                 '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:
-        if hasattr(self, 'git_revision'):
-            self.old_git_revision = self.git_revision
-            del self.git_revision
-
-        git_fetch(v, self)
-        conf['release_name'] = git_revision_name(v, self)
-        conf['git_revision'] = self.git_revision
-
-
 class ChannelSearchPath(TarrableSearchPath):
-    def pin(self, v: Verification, conf: configparser.SectionProxy) -> None:
+    def pin(self, v: Verification) -> ChannelPin:
         if hasattr(self, 'git_revision'):
             self.old_git_revision = self.git_revision
             del self.git_revision
 
-        pin_channel(v, self)
-        conf['release_name'] = self.release_name
-        conf['tarball_url'] = self.table['nixexprs.tar.xz'].absolute_url
-        conf['tarball_sha256'] = self.table['nixexprs.tar.xz'].digest
-        conf['git_revision'] = self.git_revision
+        fetch(v, self)
+        parse_channel(v, self)
+        fetch_resources(v, self)
+        ensure_git_rev_available(v, self)
+        check_channel_contents(v, self)
+        return ChannelPin(
+            release_name=self.release_name,
+            tarball_url=self.table['nixexprs.tar.xz'].absolute_url,
+            tarball_sha256=self.table['nixexprs.tar.xz'].digest,
+            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]]:
@@ -530,14 +565,6 @@ def check_channel_contents(
     v.ok()
 
 
-def pin_channel(v: Verification, channel: TarrableSearchPath) -> None:
-    fetch(v, channel)
-    parse_channel(v, channel)
-    fetch_resources(v, channel)
-    ensure_git_rev_available(v, channel)
-    check_channel_contents(v, channel)
-
-
 def git_revision_name(v: Verification, channel: TarrableSearchPath) -> str:
     v.status('Getting commit date')
     process = subprocess.run(['git',
@@ -556,11 +583,12 @@ def git_revision_name(v: Verification, channel: TarrableSearchPath) -> str:
 
 
 def read_search_path(conf: configparser.SectionProxy) -> SearchPath:
-    if 'alias_of' in conf:
-        return AliasSearchPath(**dict(conf.items()))
-    if 'channel_url' in conf:
-        return ChannelSearchPath(**dict(conf.items()))
-    return GitSearchPath(**dict(conf.items()))
+    mapping: Mapping[str, Type[SearchPath]] = {
+        'alias': AliasSearchPath,
+        'channel': ChannelSearchPath,
+        'git': GitSearchPath,
+    }
+    return mapping[conf['type']](**dict(conf.items()))
 
 
 def read_config(filename: str) -> configparser.ConfigParser:
@@ -590,7 +618,7 @@ def pin(args: argparse.Namespace) -> None:
 
         sp = read_search_path(config[section])
 
-        sp.pin(v, config[section])
+        config[section].update(sp.pin(v)._asdict())
 
     with open(args.channels_file, 'w') as configfile:
         config.write(configfile)