ci(nightly): show per-PR changelog notes on nightly updates

.github/nightly-notes/2026-10-20-ci-nightly-notes.md

@@ -0,0 +1,2 @@
+## New
+- Nightly updates now list what changed, grouped into new, improved and fixed (#1330)

.github/nightly-notes/README.md

@@ -0,0 +1,23 @@
+# Nightly notes
+
+Every pull request with a change users can notice adds one file here. On each push to `main`, CI
+merges all of them into the body of the rolling `nightly` release, which the in-app update screen
+shows to nightly testers.
+
+- Name the file `YYYY-MM-DD-<branch>.md`: the date the PR is opened, then the branch name in
+  lowercase with `/` replaced by `-`. One file per PR, and never edit another PR's file, so open
+  PRs never conflict.
+- Use only `## New`, `## Improved` and `## Fixed`, each followed by one short `- ` bullet per change.
+- Write for users, in one line per bullet, with issue numbers as `(#123)` and no em-dashes.
+- CI, test and refactor-only PRs add no file.
+
+```markdown
+## Fixed
+- Music no longer stays in audio offload after a long pause (#1364)
+```
+
+When a stable version is released, these notes are folded into `release-notes.md` and the
+`app/src/main/assets/changelog/v*.txt` changelog, and every file here except this README is deleted.
+
+`python3 .github/scripts/nightly_notes.py --check` validates the files; the Checks job runs it on
+every PR.

.github/scripts/nightly_notes.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+"""Checks the nightly notes, or merges them into the nightly release body.
+
+Each file in .github/nightly-notes/ holds one PR's user-visible changes as `## <Section>` headings
+followed by `- ` bullets. The in-app update screen (ReleaseNotes.kt) shows the intro paragraph, then
+one group per `##` section, so the merged body keeps exactly that shape.
+
+    nightly_notes.py --check
+    nightly_notes.py --intro "Built from ..." > body.md
+"""
+
+import argparse
+import pathlib
+import re
+import sys
+
+SECTIONS = ("New", "Improved", "Fixed")
+NOTES_DIR = pathlib.Path(__file__).resolve().parents[1] / "nightly-notes"
+FILE_NAME = re.compile(r"\d{4}-\d{2}-\d{2}-[a-z0-9][a-z0-9.-]*\.md")
+
+
+def read_note(path):
+    sections = {}
+    errors = []
+    current = None
+    for number, raw in enumerate(path.read_text(encoding="utf-8").splitlines(), 1):
+        line = raw.strip()
+        where = f"{path.name}:{number}"
+        if not line:
+            continue
+        if "—" in line:
+            errors.append(f"{where}: no em-dashes in user-facing copy")
+        if line.startswith("## "):
+            current = line[3:].strip()
+            if current not in SECTIONS:
+                errors.append(f"{where}: section '{current}' must be one of {', '.join(SECTIONS)}")
+            sections.setdefault(current, [])
+        elif line.startswith("- "):
+            if current is None:
+                errors.append(f"{where}: bullet before any '## Section' heading")
+            else:
+                sections[current].append(line[2:].strip())
+        else:
+            errors.append(f"{where}: expected a '## Section' heading or a '- ' bullet")
+    if not any(sections.values()):
+        errors.append(f"{path.name}: has no bullets")
+    return sections, errors
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__, formatter_class=argparse.RawDescriptionHelpFormatter)
+    parser.add_argument("--check", action="store_true", help="only validate the notes")
+    parser.add_argument("--intro", default="", help="paragraph shown above the sections")
+    args = parser.parse_args()
+
+    notes = sorted(path for path in NOTES_DIR.glob("*.md") if path.name != "README.md")
+    merged = {section: [] for section in SECTIONS}
+    errors = []
+    # File names start with the date, so reversed order lists the newest changes first.
+    for path in reversed(notes):
+        if not FILE_NAME.fullmatch(path.name):
+            errors.append(f"{path.name}: name must be YYYY-MM-DD-<branch>.md in lowercase")
+        sections, problems = read_note(path)
+        errors += problems
+        for section, items in sections.items():
+            merged.setdefault(section, []).extend(items)
+
+    if errors:
+        print("\n".join(errors), file=sys.stderr)
+        return 1
+    if args.check:
+        print(f"{len(notes)} nightly notes are valid.")
+        return 0
+
+    lines = [args.intro] if args.intro else []
+    for section in SECTIONS:
+        if merged[section]:
+            lines += ["", f"## {section}", *(f"- {item}" for item in merged[section])]
+    print("\n".join(lines).strip())
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())

.github/workflows/build.yml

@@ -70,6 +70,10 @@ jobs:
           git status --porcelain -- app/src/main/java/org/tartarus/snowball
           test -z "$(git status --porcelain -- app/src/main/java/org/tartarus/snowball)"
 
+      # The nightly job publishes these as the release body the update screen shows.
+      - name: Check nightly notes
+        run: python3 .github/scripts/nightly_notes.py --check
+
       - name: Check Kotlin formatting
         run: >
           ./gradlew spotlessCheck
@@ -457,6 +461,14 @@ jobs:
       cancel-in-progress: false
 
     steps:
+      - name: Checkout nightly notes
+        uses: actions/checkout@v7
+        with:
+          ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
+          sparse-checkout: |
+            .github/nightly-notes
+            .github/scripts
+
       - name: Download nightly APK
         uses: actions/download-artifact@v8
         with:
@@ -483,9 +495,12 @@ jobs:
               gh release delete-asset nightly "$old" --yes
             fi
           done
+          python3 .github/scripts/nightly_notes.py \
+            --intro "Built from ${GITHUB_SHA::7} by run ${GITHUB_RUN_NUMBER}. Installs next to the stable app as Flow Nightly and updates itself from here." \
+            > nightly-body.md
           gh release edit nightly --prerelease --latest=false \
             --title "Flow nightly ${GITHUB_RUN_NUMBER}" \
-            --notes "Built from ${GITHUB_SHA::7} by run ${GITHUB_RUN_NUMBER}. Installs next to the stable app as Flow Nightly and updates itself from here."
+            --notes-file nightly-body.md
 
   release:
     name: Create Release

AGENTS.md

@@ -450,6 +450,16 @@ rows, bespoke empty/error states, bespoke badges, bespoke formatters, or a secon
 3. Follow current Kotlin and Android best practices — when unsure, check official docs rather than guessing.
 4. DO NOT edit the app's Room database schema without explicit instruction (schema changes require a version bump and migration, handled deliberately).
 5. DO NOT bump the app version in any file — version bumps are done manually by the project owner.
+6. Every PR with a change users can notice adds a nightly note: one new file
+   `.github/nightly-notes/YYYY-MM-DD-<branch>.md` (the date the PR is opened, the branch name in
+   lowercase with `/` replaced by `-`) holding `## New`, `## Improved` or `## Fixed` headings, each
+   with one short `- ` bullet per change, written for users, issues as `(#123)`, no em-dashes. One
+   file per PR, never edit another PR's file. CI, test and refactor-only PRs add none. CI publishes
+   every note as the nightly release body that the in-app update screen shows, and the Checks job
+   fails on a malformed note (`python3 .github/scripts/nightly_notes.py --check`). This is separate
+   from the release changelog in `app/src/main/assets/changelog/v*.txt`; at a stable release the
+   notes are folded into it and into `release-notes.md`, and the note files are deleted (keep the
+   folder's `README.md`).
 
 ## AI-only guidelines