Release notes that are not forty lines of base64

Found by documenting it. `_notes_for` stripped `-----BEGIN PGP SIGNATURE-----`
from an annotated tag's contents and nothing else, and which header appears
depends on `gpg.format`: `openpgp` writes that one, `ssh` writes
`-----BEGIN SSH SIGNATURE-----`. This repository signs with an SSH key, so the
first signed release tag would have rendered its whole signature block as the
release notes on the update page.

`%(contents:subject)` and `%(contents:body)` would have avoided the question,
and would also have thrown away every blank line in a body written as a list --
which is what release notes are.

The suite caught the other half of the same change: `tag.gpgSign` makes a bare
`git tag <name>` behave as `-s`, so the lightweight tags a test was making now
wait for an editor it does not have.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/test_updates.py

@@ -144,6 +144,36 @@ def test_stable_picks_the_newest_release_and_reads_its_notes(db, tagged):
     assert "one thing" in target.notes
 
 
+def test_a_signed_tag_shows_notes_and_not_base64(db):
+    """`%(contents)` carries the signature block, and which header it uses
+    depends on `gpg.format` -- PGP for `openpgp`, SSH for `ssh`. Stripping only
+    the first would have rendered forty lines of base64 as the release notes on
+    a repository that signs with an SSH key, which is this one."""
+    import subprocess
+
+    root = updates.checkout_dir()
+    subprocess.run(
+        ["git", "tag", "-a", "v9.9.8", "-m", "Signed release.\n\n- a note"],
+        cwd=root, check=True, capture_output=True,
+    )
+    try:
+        code, raw = updates._git(
+            ["for-each-ref", "--format=%(contents)", "refs/tags/v9.9.8"], cwd=root
+        )
+        notes = updates._notes_for(root, "v9.9.8")
+    finally:
+        subprocess.run(
+            ["git", "tag", "-d", "v9.9.8"], cwd=root, check=False, capture_output=True
+        )
+
+    assert code == 0
+    # Only meaningful while this repository actually signs its tags; when it
+    # does, the raw contents carry a block and the notes must not.
+    if any(header in raw for header in updates._SIGNATURE_HEADERS):
+        assert not any(header in notes for header in updates._SIGNATURE_HEADERS)
+    assert notes == "Signed release.\n\n- a note"
+
+
 def test_a_version_sort_is_not_a_lexical_one(db, tagged):
     """`v1.10.0` above `v1.9.0`, which a lexical sort gets wrong -- and gets
     wrong silently the first time a project reaches ten of anything."""
@@ -151,7 +181,12 @@ def test_a_version_sort_is_not_a_lexical_one(db, tagged):
 
     root = updates.checkout_dir()
     for tag in ("v1.9.0", "v1.10.0"):
-        subprocess.run(["git", "tag", tag], cwd=root, check=True, capture_output=True)
+        # `-m` rather than a lightweight tag: this repository sets
+        # `tag.gpgSign`, which makes a bare `git tag <name>` behave as `-s` and
+        # wait for an editor that a test does not have.
+        subprocess.run(
+            ["git", "tag", "-m", tag, tag], cwd=root, check=True, capture_output=True
+        )
     try:
         tags = updates.release_tags(root)
         assert tags.index("v1.10.0") < tags.index("v1.9.0")