From 096a2d94655ee349c78abd7afe9b6d09d4c58d43 Mon Sep 17 00:00:00 2001
From: Justus Magin <keewis@posteo.de>
Date: Mon, 29 Jul 2024 15:03:42 +0200
Subject: [PATCH 1/3] script to generate the release string

---
 ci/release_contributors.py | 49 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)
 create mode 100644 ci/release_contributors.py

diff --git a/ci/release_contributors.py b/ci/release_contributors.py
new file mode 100644
index 00000000000..dab95c651c5
--- /dev/null
+++ b/ci/release_contributors.py
@@ -0,0 +1,49 @@
+import re
+import textwrap
+
+import git
+from tlz.itertoolz import last, unique
+
+co_author_re = re.compile(r"Co-authored-by: (?P<name>[^<]+?) <(?P<email>.+)>")
+
+
+def main():
+    repo = git.Repo(".")
+
+    most_recent_release = last(repo.tags)
+
+    # extract information from commits
+    contributors = {}
+    for commit in repo.iter_commits(f"{most_recent_release.name}.."):
+        matches = co_author_re.findall(commit.message)
+        if matches:
+            contributors.update({email: name for name, email in matches})
+        contributors[commit.author.email] = commit.author.name
+
+    # deduplicate and ignore
+    # TODO: extract ignores from .github/release.yml
+    ignored = ["dependabot", "pre-commit-ci"]
+    unique_contributors = unique(
+        contributor
+        for contributor in contributors.values()
+        if contributor.removesuffix("[bot]") not in ignored
+    )
+
+    sorted_ = sorted(unique_contributors)
+    if len(sorted_) > 1:
+        names = f"{', '.join(sorted_[:-1])} and {sorted_[-1]}"
+    else:
+        names = "".join(sorted_)
+
+    statement = textwrap.dedent(
+        f"""\
+    Thanks to the {len(sorted_)} contributors to this release:
+    {names}
+    """.rstrip()
+    )
+
+    print(statement)
+
+
+if __name__ == "__main__":
+    main()

From b5b34fe6fc965d1386c112d99458ca48c7f39d98 Mon Sep 17 00:00:00 2001
From: Justus Magin <keewis@posteo.de>
Date: Mon, 29 Jul 2024 15:05:35 +0200
Subject: [PATCH 2/3] use the new script in the release guide

---
 HOW_TO_RELEASE.md | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/HOW_TO_RELEASE.md b/HOW_TO_RELEASE.md
index 9d1164547b9..629c444d63f 100644
--- a/HOW_TO_RELEASE.md
+++ b/HOW_TO_RELEASE.md
@@ -23,14 +23,13 @@ upstream        https://github.com/pydata/xarray (push)
     ```sh
     git fetch upstream --tags
     ```
-    This will return a list of all the contributors since the last release:
+    Then run
     ```sh
-    git log "$(git tag --sort=v:refname | tail -1).." --format=%aN | sort -u | perl -pe 's/\n/$1, /'
-    ```
-    This will return the total number of contributors:
-    ```sh
-    git log "$(git tag --sort=v:refname | tail -1).." --format=%aN | sort -u | wc -l
+    python ci/release_contributors.py
     ```
+    (needs `gitpython`)
+
+    and copy the output.
  3. Write a release summary: ~50 words describing the high level features. This
     will be used in the release emails, tweets, GitHub release notes, etc.
  4. Look over whats-new.rst and the docs. Make sure "What's New" is complete

From 04fd9c2502ba5e387cd0429a8914bb9afbb4b615 Mon Sep 17 00:00:00 2001
From: Justus Magin <keewis@posteo.de>
Date: Mon, 29 Jul 2024 15:18:14 +0200
Subject: [PATCH 3/3] include `toolz` in the deps

---
 HOW_TO_RELEASE.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/HOW_TO_RELEASE.md b/HOW_TO_RELEASE.md
index 629c444d63f..28f7b8e8775 100644
--- a/HOW_TO_RELEASE.md
+++ b/HOW_TO_RELEASE.md
@@ -27,7 +27,7 @@ upstream        https://github.com/pydata/xarray (push)
     ```sh
     python ci/release_contributors.py
     ```
-    (needs `gitpython`)
+    (needs `gitpython` and `toolz` / `cytoolz`)
 
     and copy the output.
  3. Write a release summary: ~50 words describing the high level features. This