Hard-code conda channel into asv_delegated_conda.py (#5435)

* What's new entry.

* What's New entry.

* Hard-code conda channel into asv_delegated_conda.py .

* Fix some rebase confusion in the What's New.

benchmarks/asv.conf.json

@@ -4,7 +4,6 @@
     "project_url": "https://github.com/SciTools/iris",
     "repo": "..",
     "environment_type": "conda-delegated",
-    "conda_channels": ["conda-forge", "defaults"],
     "show_commit_url": "http://github.com/scitools/iris/commit/",
     "branches": ["upstream/main"],
 

benchmarks/asv_delegated_conda.py

@@ -66,6 +66,8 @@ def __init__(
             ignored.append("`requirements`")
         if tagged_env_vars:
             ignored.append("`tagged_env_vars`")
+        if conf.conda_channels:
+            ignored.append("conda_channels")
         if conf.conda_environment_file:
             ignored.append("`conda_environment_file`")
         message = (
@@ -75,6 +77,8 @@ def __init__(
         log.warning(message)
         requirements = {}
         tagged_env_vars = {}
+        # All that is required to create ASV's bare-bones environment.
+        conf.conda_channels = ["defaults"]
         conf.conda_environment_file = None
 
         super().__init__(conf, python, requirements, tagged_env_vars)

docs/src/whatsnew/latest.rst

@@ -97,6 +97,7 @@ This document explains the changes made to Iris for this release
    error. This fixes an oversight introduced in :pull:`5215`. (feature branch:
    :pull`5434`)
 
+
 .. comment
     Whatsnew author names (@github name) in alphabetical order. Note that,
     core dev names are automatically included by the common_links.inc: