Fix handling of channels from prefixes (#328)

* Fix handling of channels from prefixes

* Draft

* Implement channels extracting behavior

* Remove debug log

Author: martinRenou

jupyterlite_xeus/add_on.py

@@ -4,6 +4,7 @@
 import os
 from pathlib import Path
 import shutil
+import shlex
 from tempfile import TemporaryDirectory
 from urllib.parse import urlparse
 import warnings
@@ -158,8 +159,7 @@ def post_build(self, manager):
                     raise ValueError(f"Environment name '{env_name}' used more than once")
                 self.prefixes[env_name] = prefix
                 self.specs[env_name] = self.get_environment_specs(prefix)
-                # For lack of a better way for now
-                self.channels[env_name] = DEFAULT_CHANNELS
+                self.channels[env_name] = self.get_environment_channels(prefix)
 
         all_kernels = []
         for env_name, prefix in self.prefixes.items():
@@ -196,6 +196,35 @@ def get_environment_specs(self, prefix):
                         print(f"Error parsing line: {spec_line} — {e}")
         return specs
 
+    def get_environment_channels(self, prefix):
+        if isinstance(prefix, str):
+            history_file_path = Path(prefix)
+        path = history_file_path / "conda-meta" / "history"
+        channels = []
+        with open(path, "r") as f:
+            for line in f:
+                if line.startswith("# cmd:"):
+                    tokens = shlex.split(line.replace("# cmd:", ""))
+                    i = 0
+                    while i < len(tokens):
+                        tok = tokens[i]
+
+                        # Handle "-c URL" or "--channel URL"
+                        if tok in ("-c", "--channel"):
+                            if i + 1 < len(tokens):
+                                channels.append(tokens[i + 1])
+                            i += 2
+                            continue
+
+                        # Handle "--channel=URL"
+                        if tok.startswith("--channel="):
+                            channels.append(tok.split("=", 1)[1])
+                            i += 1
+                            continue
+
+                        i += 1
+        return channels
+
     def create_prefix(self, env_file: Path):
         # read the environment file
         root_prefix = Path(self.cwd_name) / "_env"

tests/test_xeus.py

@@ -210,8 +210,6 @@ def test_multiple_envs():
         update_action_args = update_cp_env_steps["actions"][0][1]
         expected_tmp_path = update_action_args[0]
         assert expected_tmp_path.name == "empack_env_meta.json"
-        assert isinstance(update_action_args[1], dict)
-        assert "specs" in update_action_args[1]
 
         copy_action_args = update_cp_env_steps["actions"][1][1]
         assert copy_action_args[1] == target_path / env_name_tmp / "empack_env_meta.json"