Better error message for running "update" before "pin"

[pinch] / pinch.py

diff --git a/pinch.py b/pinch.py
index b044faf34c0304dbdd20b55c84c9d27bd1b3832a..f84440c5c0fd54e4831b893edc4c7ed94a446909 100644 (file)
--- a/pinch.py
+++ b/pinch.py
@@ -25,6 +25,9 @@ from typing import (
     Tuple,
 )
 
+import xdg
+
+
 Digest16 = NewType('Digest16', str)
 Digest32 = NewType('Digest32', str)
 
@@ -216,9 +219,9 @@ def fetch_resources(v: Verification, channel: Channel) -> None:
 
 
 def git_cachedir(git_repo: str) -> str:
-    # TODO: Consider using pyxdg to find this path.
-    return os.path.expanduser(
-        '~/.cache/pinch/git/%s' %
+    return os.path.join(
+        xdg.XDG_CACHE_HOME,
+        'pinch/git',
         digest_string(
             git_repo.encode()))
 
@@ -360,7 +363,8 @@ def git_checkout(v: Verification, channel: Channel, dest: str) -> None:
                            stdout=subprocess.PIPE)
     tar = subprocess.Popen(
         ['tar', 'x', '-C', dest, '-f', '-'], stdin=git.stdout)
-    git.stdout.close()
+    if git.stdout:
+        git.stdout.close()
     tar.wait()
     git.wait()
     v.result(git.returncode == 0 and tar.returncode == 0)
@@ -451,7 +455,7 @@ def git_revision_name(v: Verification, channel: Channel) -> str:
                               '--abbrev=11',
                               channel.git_revision],
                              capture_output=True)
-    v.result(process.returncode == 0 and process.stdout != '')
+    v.result(process.returncode == 0 and process.stdout != b'')
     return '%s-%s' % (os.path.basename(channel.git_repo),
                       process.stdout.decode().strip())
 
@@ -496,7 +500,7 @@ def pin(args: argparse.Namespace) -> None:
 def update(args: argparse.Namespace) -> None:
     v = Verification()
     config = configparser.ConfigParser()
-    exprs = {}
+    exprs: Dict[str, str] = {}
     configs = [read_config(filename) for filename in args.channels_file]
     for config in configs:
         for section in config.sections():
@@ -505,6 +509,11 @@ def update(args: argparse.Namespace) -> None:
                 assert 'git_repo' not in config[section]
                 continue
 
+            if 'git_repo' not in config[section] or 'release_name' not in config[section]:
+                raise Exception(
+                    'Cannot update unpinned channel "%s" (Run "pin" before "update")' %
+                    section)
+
             if 'channel_url' in config[section]:
                 tarball = fetch_with_nix_prefetch_url(
                     v, config[section]['tarball_url'], Digest16(
@@ -514,6 +523,8 @@ def update(args: argparse.Namespace) -> None:
                 ensure_git_rev_available(v, channel)
                 tarball = git_get_tarball(v, channel)
 
+            if section in exprs:
+                raise Exception('Duplicate channel "%s"' % section)
             exprs[section] = (
                 'f: f { name = "%s"; channelName = "%%s"; src = builtins.storePath "%s"; }' %
                 (config[section]['release_name'], tarball))
@@ -521,6 +532,8 @@ def update(args: argparse.Namespace) -> None:
     for config in configs:
         for section in config.sections():
             if 'alias_of' in config[section]:
+                if section in exprs:
+                    raise Exception('Duplicate channel "%s"' % section)
                 exprs[section] = exprs[str(config[section]['alias_of'])]
 
     command = [