.env.example

@@ -1,22 +1,29 @@
 # Copy to .env and fill in. .env is gitignored — the real registry hostname
 # must not end up in the repository.
 
-# Image coordinates. FOODSTER_REPO carries no tag.
-FOODSTER_REPO=registry.example.com/you/foodster
-FOODSTER_TAG=latest
+# Image coordinates. REPO carries no tag.
+REPO=registry.example.com/you/foodster
+TAG=latest
 
 # Shared household password. The app will not start without it.
-FOODSTER_PASSWORD=changeme
+PASSWORD=changeme
 
 # Hostname Traefik routes to. Kept here rather than in compose.yaml so no
 # infrastructure detail is committed.
-FOODSTER_HOST=foodster.example.com
+HOST=foodster.example.com
+
+# Anything other than prod is written into the browser tab title, so a dev
+# instance open beside the real one can be told apart.
+ENV=prod
 
 # The database lives in ./data, bind-mounted into the container. These must
 # match whoever owns that directory on the host, or the container cannot
 # write to it. `id -u` and `id -g` will tell you.
-FOODSTER_UID=1000
-FOODSTER_GID=1000
+#
+# Named PUID/PGID because UID is read-only in bash and a plain UID here would
+# be quietly replaced by the invoking shell's own.
+PUID=1000
+PGID=1000
 
 # Used for every calendar-day calculation. Set it in development too: under
 # UTC the date rolls over three hours late, which is exactly when dinner

CONTRIBUTING.md

@@ -0,0 +1,94 @@
+# Contributing
+
+A household project, so this is less a set of rules than a note to whoever
+picks it up next — including me in six months.
+
+## Getting set up
+
+```sh
+cp .env.example .env      # then edit it
+make run                  # http://localhost:8080, tab titled "dev · Foodster"
+make                      # every target, with a one-line description
+```
+
+`make check` is the gate: `go vet`, gofmt, unit tests, and `scripts/smoke.sh`,
+which drives a real server over HTTP. Run it before every commit.
+
+## Branches
+
+`dev` is where work happens. `main` holds released versions only — it is
+protected on the remote and takes no direct pushes, so a release arrives as a
+pull request from `dev`, squash-merged.
+
+After a squash merge, reset `dev` onto it or the next pull request will offer
+the same commits again:
+
+```sh
+git switch main && git pull --ff-only
+git switch dev && git reset --hard main
+git push --force-with-lease origin dev
+```
+
+`make image` refuses to run outside `main`. That check has to be local: the
+tag and the image are made before anything reaches the remote, so branch
+protection cannot catch a release built from the wrong branch.
+
+## Commit messages
+
+Conventional Commits — a type, an optional scope, then a short subject in the
+imperative.
+
+```
+feat(kirjaa): expand the selected day in place
+fix: redirect the catalog to /ruuat, not /ruoat
+chore(deps): bump the vendored Datastar client
+```
+
+| Type | For |
+|---|---|
+| `feat` | new behaviour someone will notice |
+| `fix` | a bug, ideally naming what broke |
+| `refactor` | same behaviour, different shape |
+| `test` | tests only |
+| `docs` | documentation only |
+| `build` | Makefile, Containerfile, compose, CI |
+| `chore` | anything else: dependencies, seeds, tidying |
+
+**The body matters more than the type.** Explain *why*, and what the
+alternative was — the diff already says what changed. If a fix was subtle,
+say what made it subtle; if a test caught something, say what. Commits here
+are the only design record this project has.
+
+### Release pull requests
+
+Because `main` is squash-merged, a pull request title becomes a commit message
+on `main`. A release spans a fix, a feature and some chores at once, so none
+of the types above fits it honestly. Use `release:` instead:
+
+```
+release: repair the catalog 404 and stop the page jumping
+```
+
+`main`'s log is then one line per deployment, which is what that branch is
+for, and the pull request body serves as the release notes. No version in the
+title — the CalVer tag is not created until `make image` runs after the merge.
+
+The types above are for `dev`, where a commit really does do one thing.
+
+## Things that are easy to get wrong
+
+- **The interface is Finnish.** Code, comments, this file and the PRD are
+  English. There is no i18n layer and no language switcher.
+- **No infrastructure detail is committed** — no hostnames, registry paths or
+  ports. They live in `.env`, which is gitignored, because the PRD leaves the
+  door open to publishing this repository.
+- **Migrations are immutable once shipped.** A released migration has run on a
+  live database and will not run again. Add a new numbered file instead.
+- **Interactions patch, they do not navigate.** Anything that reloads the page
+  loses the scroll position, which on a long list is maddening. Links stay
+  links and forms stay forms so it works without JavaScript; Datastar layers
+  over them with `data-on:click__prevent` and `data-on:submit__prevent`.
+- **A `ponytail:` comment marks a deliberate shortcut** and names its ceiling,
+  so the next reader can tell a decision from an oversight.
+- **Assert what a response does, not just that it responded.** A redirect to a
+  dead URL is still a 303; that one shipped.

Makefile

@@ -38,7 +38,7 @@ build: generate ## Build ./foodster
 		-ldflags="-s -w -X main.version=dev" -o $(BIN) $(PKG)
 
 run: generate ## Run locally on :8080 (database in ./data)
-	FOODSTER_PASSWORD=$${FOODSTER_PASSWORD:-dev} go run $(PKG)
+	PASSWORD=$${PASSWORD:-dev} ENV=dev go run $(PKG)
 
 seed: ## Import a dish bundle (SEED=seeds/testi.json)
 	go run $(PKG) -import $(SEED)
@@ -85,7 +85,7 @@ fix: ## Format Go and templ sources, tidy go.mod
 	go mod tidy
 
 image: ## Build and tag an image as vYYYYMMDD-N. Creates a git tag.
-	@test -n "$(FOODSTER_REPO)" || { echo "set FOODSTER_REPO in .env"; exit 1; }
+	@test -n "$(REPO)" || { echo "set REPO in .env"; exit 1; }
 	@# A release tag must point into main, or the tag records a commit that
 	@# was never released.
 	@branch=$$(git symbolic-ref --short HEAD); \
@@ -99,7 +99,7 @@ image: ## Build and tag an image as vYYYYMMDD-N. Creates a git tag.
 	echo "==> $$tag"; \
 	git tag "$$tag"; \
 	podman build --platform linux/amd64 --build-arg VERSION="$$tag" \
-		-t "$(FOODSTER_REPO):$$tag" -t "$(FOODSTER_REPO):latest" . ; \
+		-t "$(REPO):$$tag" -t "$(REPO):latest" . ; \
 	echo "$$tag" > $(TAGFILE)
 
 # Pushing reported success while uploading the previous release once, because
@@ -107,18 +107,18 @@ image: ## Build and tag an image as vYYYYMMDD-N. Creates a git tag.
 # registry what it actually serves for each tag and fail if it is not the
 # image we just built.
 push: ## Push the newest tag and :latest, then verify the registry
-	@test -n "$(FOODSTER_REPO)" || { echo "set FOODSTER_REPO in .env"; exit 1; }
+	@test -n "$(REPO)" || { echo "set REPO in .env"; exit 1; }
 	@test -f $(TAGFILE) || { echo "nothing built - run make image"; exit 1; }; \
 	tag=$$(cat $(TAGFILE)); \
-	built=$$(podman image inspect "$(FOODSTER_REPO):$$tag" --format '{{.Id}}' 2>/dev/null) || \
+	built=$$(podman image inspect "$(REPO):$$tag" --format '{{.Id}}' 2>/dev/null) || \
 		{ echo "no local image tagged $$tag - run make image"; exit 1; }; \
-	podman push "$(FOODSTER_REPO):$$tag"; \
-	podman push "$(FOODSTER_REPO):latest"; \
+	podman push "$(REPO):$$tag"; \
+	podman push "$(REPO):latest"; \
 	echo "==> verifying $$tag"; \
 	for ref in "$$tag" latest; do \
-		podman pull -q "$(FOODSTER_REPO):$$ref" >/dev/null 2>&1 || \
+		podman pull -q "$(REPO):$$ref" >/dev/null 2>&1 || \
 			{ echo "  FAIL  $$ref is not in the registry"; exit 1; }; \
-		served=$$(podman image inspect "$(FOODSTER_REPO):$$ref" --format '{{.Id}}'); \
+		served=$$(podman image inspect "$(REPO):$$ref" --format '{{.Id}}'); \
 		if [ "$$served" != "$$built" ]; then \
 			echo "  FAIL  $$ref serves $$served"; \
 			echo "        expected $$built"; \

PRD.md

@@ -351,7 +351,7 @@ build and no asset bundler.
   is imported because the runtime image carries no zoneinfo. All date logic
   uses that location explicitly and never `time.Local`.
 - **Auth**: HTTP Basic with one shared household password read from
-  `FOODSTER_PASSWORD`; the username is ignored. Compared using
+  `PASSWORD`; the username is ignored. Compared using
   `subtle.ConstantTimeCompare` over SHA-256 digests so neither the value nor
   its length leaks through timing. `/healthz` is the only route outside auth.
 - **Exposure**: the app is served on a public hostname behind Traefik, which
@@ -395,21 +395,25 @@ on the server and run with Docker Compose.
   `/data/foodster.db`, bind-mounted from `./data` on the host rather than
   kept in a named volume, so the file can be listed and copied without going
   through the container engine. Backup is `cp -r data`. Because the image
-  runs as UID 65534, compose sets `user:` from `FOODSTER_UID`/`FOODSTER_GID`
+  runs as UID 65534, compose sets `user:` from `PUID`/`PGID`
   to match whoever owns that directory. `restart: unless-stopped`.
 - **Configuration**, entirely through environment variables (see
   `.env.example`):
-  - `FOODSTER_REPO` and `FOODSTER_TAG` — image coordinates.
-  - `FOODSTER_PASSWORD` — the shared password. Required; the app refuses to
-    start without it.
-  - `FOODSTER_DB` — database file path, default `./data/foodster.db`. The
-    directory is created on startup if missing.
-  - `FOODSTER_UID` / `FOODSTER_GID` — host owner of `./data`.
+  Names carry no application prefix: the container namespaces them already.
+  - `REPO` and `TAG` — image coordinates.
+  - `PASSWORD` — the shared password. Required; the app refuses to start
+    without it.
+  - `DB` — database file path, default `./data/foodster.db`. The directory is
+    created on startup if missing.
+  - `ENV` — anything but `prod` is prefixed to the browser tab title, so a
+    dev instance open beside the real one can be told apart.
+  - `PUID` / `PGID` — host owner of `./data`. Not `UID`, which is read-only
+    in bash and would be replaced by the invoking shell's own value.
   - `TZ` — default `Europe/Helsinki`.
 - The registry hostname exists only in `.env`, which is gitignored, because
   §11 leaves open the possibility of publishing this repository.
 - **Routing**: Traefik on an external `traefik` network, matching on
-  `FOODSTER_HOST` and terminating TLS. The container publishes no ports —
+  `HOST` and terminating TLS. The container publishes no ports —
   doing so would put an unencrypted copy of the app on the host, bypassing
   the proxy. The hostname lives in `.env` rather than `compose.yaml`, so no
   infrastructure detail is committed.

README.md

@@ -58,6 +58,9 @@ One static Go binary. No Node.js, no bundler, no separate database server.
 | Auth | HTTP Basic, one shared household password |
 | Runtime image | `FROM scratch` |
 
+Working on it: [CONTRIBUTING.md](CONTRIBUTING.md) — branches, commit messages,
+and the conventions that are easy to miss.
+
 ## Branches
 
 `main` holds released versions only. Every release tag points at a commit on
@@ -173,13 +176,19 @@ Everything is environment variables. `.env` is gitignored; start from
 
 | Variable | Default | Purpose |
 |---|---|---|
-| `FOODSTER_PASSWORD` | *required* | Shared password. The app will not start without it. |
-| `FOODSTER_DB` | `./data/foodster.db` | SQLite file path; the directory is created if missing. |
-| `FOODSTER_UID` / `FOODSTER_GID` | `1000` | Host owner of `./data`, for the bind mount. |
+| `PASSWORD` | *required* | Shared password. The app will not start without it. |
+| `DB` | `./data/foodster.db` | SQLite file path; the directory is created if missing. |
+| `ENV` | `prod` | Anything else is prefixed to the tab title (`dev · Foodster`). |
+| `ADDR` | `:8080` | Listen address. Only useful for a second local instance. |
+| `PUID` / `PGID` | `1000` | Host owner of `./data`, for the bind mount. |
 | `TZ` | `Europe/Helsinki` | Used for every calendar-day calculation. |
-| `FOODSTER_REPO` | *required to build* | Image repository, no tag. |
-| `FOODSTER_TAG` | `latest` | Tag to run under compose. |
-| `FOODSTER_PORT` | `8080` | Host port to publish. |
+
+Names carry no prefix: the container gives them their own namespace already.
+`PUID`/`PGID` are the exception — `UID` is read-only in bash, so a value set
+in `.env` would be silently replaced by the invoking shell's own.
+| `REPO` | *required to build* | Image repository, no tag. |
+| `TAG` | `latest` | Tag to run under compose. |
+| `HOST` | *required to run* | Hostname Traefik routes to. |
 
 Set `TZ` in development too. Under UTC the date rolls over three hours late,
 which is exactly when dinner gets logged.
@@ -204,7 +213,7 @@ the container, so a backup is `cp -r data` and you can inspect the file with
 any sqlite client without going through the engine.
 
 That directory must exist and be owned by the user compose runs as — `make up`
-creates it, and `FOODSTER_UID`/`FOODSTER_GID` in `.env` tell the container who
+creates it, and `PUID`/`PGID` in `.env` tell the container who
 that is. Get them from `id -u` and `id -g`.
 
 If the app exits with `cannot open /data/foodster.db ... unable to open
@@ -213,7 +222,7 @@ bind-mount directory as root, and the container is not root:
 
 ```sh
 ls -ldn data                      # whose is it?
-sudo chown -R 1000:1000 data      # match FOODSTER_UID / FOODSTER_GID
+sudo chown -R 1000:1000 data      # match PUID / PGID
 docker compose restart
 ```
 
@@ -235,7 +244,7 @@ counting it would lock the household out for simply opening the app.
 address, meaning it arrived through the proxy. A client connecting directly
 could otherwise forge a new address per attempt and skip the limiter.
 
-**None of this replaces a strong `FOODSTER_PASSWORD`.** Rate limiting removes
+**None of this replaces a strong `PASSWORD`.** Rate limiting removes
 brute force as a practical route; it does not make a guessable password safe.
 
 ## Mockups

cmd/foodster/handlers.go

@@ -98,16 +98,56 @@ type logView struct {
 	Confirming bool
 }
 
-func (a *app) index(w http.ResponseWriter, r *http.Request) {
-	date := a.date(r)
-	v := logView{
-		Date:    date,
-		Today:   today(a.loc),
-		Search:  strings.TrimSpace(r.URL.Query().Get("haku")),
-		Checked: map[int64]bool{},
-	}
+// logOptions is what the Kirjaa screen is being asked to show. Pulled out of
+// the request for a page load or a patch, and set directly after a write,
+// where the answer is simply "that day, nothing else open".
+type logOptions struct {
+	Date       time.Time
+	Dish       string // ?ruoka=, opening the sides step
+	Changing   bool   // ?muuta=, swapping the dish on a logged day
+	Confirming bool   // ?poista=, asking before deleting the entry
+	Search     string
+}
 
-	v.Confirming = r.URL.Query().Get("poista") != ""
+func (a *app) logOptionsFrom(r *http.Request) logOptions {
+	q := r.URL.Query()
+	return logOptions{
+		Date:       a.date(r),
+		Dish:       q.Get("ruoka"),
+		Changing:   q.Get("muuta") != "",
+		Confirming: q.Get("poista") != "",
+		Search:     strings.TrimSpace(q.Get("haku")),
+	}
+}
+
+func (a *app) index(w http.ResponseWriter, r *http.Request) {
+	render(w, r, logPage(a.buildLog(r, a.logOptionsFrom(r))))
+}
+
+// day patches the list in place. Every link in it calls here rather than
+// loading a page, so opening a day leaves the scroll position alone.
+func (a *app) day(w http.ResponseWriter, r *http.Request) {
+	fragment(w, r, dayList(a.buildLog(r, a.logOptionsFrom(r))))
+}
+
+// finishDay answers a write: a patch for Datastar, a redirect otherwise.
+func (a *app) finishDay(w http.ResponseWriter, r *http.Request, date time.Time) {
+	if isDatastar(r) {
+		fragment(w, r, dayList(a.buildLog(r, logOptions{Date: date})))
+		return
+	}
+	a.redirectToDay(w, r, date)
+}
+
+func (a *app) buildLog(r *http.Request, o logOptions) logView {
+	date := o.Date
+	v := logView{
+		Date:       date,
+		Today:      today(a.loc),
+		Search:     o.Search,
+		Checked:    map[int64]bool{},
+		Confirming: o.Confirming,
+	}
 
 	entry, err := entryFor(a.db, date)
 	if err != nil {
@@ -118,8 +158,8 @@ func (a *app) index(w http.ResponseWriter, r *http.Request) {
 	// ?ruoka= opens the sides step for that dish. When it is the dish already
 	// logged, the existing sides come back ticked, which makes editing an
 	// entry the same screen as creating one.
-	if raw := r.URL.Query().Get("ruoka"); raw != "" {
-		if id, err := strconv.ParseInt(raw, 10, 64); err == nil {
+	if o.Dish != "" {
+		if id, err := strconv.ParseInt(o.Dish, 10, 64); err == nil {
 			if dish, err := dishByID(a.db, id); err == nil {
 				v.Chosen = dish
 				if entry != nil && entry.Main.ID == id {
@@ -134,7 +174,7 @@ func (a *app) index(w http.ResponseWriter, r *http.Request) {
 	// The board shows when there is nothing logged yet, or when the entry is
 	// being changed. "Muokkaa" on a logged day sets ?muuta=1 and lands here,
 	// so swapping the dish and picking one for the first time are one path.
-	changing := r.URL.Query().Get("muuta") != "" || v.Search != ""
+	changing := o.Changing || v.Search != ""
 	if v.Chosen == nil && (v.Entry == nil || changing) {
 		v.ShowBoard = true
 		if v.Dishes, err = listDishes(a.db, v.Search); err != nil {
@@ -157,7 +197,7 @@ func (a *app) index(w http.ResponseWriter, r *http.Request) {
 	}
 
 	a.loadDays(r, &v)
-	render(w, r, logPage(v))
+	return v
 }
 
 // loadDays fills the day list. The selected day expands inside it rather than
@@ -215,6 +255,50 @@ func fragment(w http.ResponseWriter, r *http.Request, c templ.Component) {
 	}
 }
 
+// isDatastar reports whether the request came from the client library, which
+// tags its own. Everything below keeps working without JavaScript: the same
+// handlers redirect instead of patching when the header is absent.
+func isDatastar(r *http.Request) bool {
+	return r.Header.Get("Datastar-Request") != ""
+}
+
+// patchElements sends one Datastar event carrying several elements, each
+// matched to the page by its id. A text/html response can only replace one
+// element, and the catalog has to move its list and its forms together —
+// opening an edit form also has to un-highlight whatever was open before.
+//
+// ponytail: about twenty lines instead of the SDK, which brought four modules
+// for an SSE generator we would otherwise never call.
+func patchElements(w http.ResponseWriter, r *http.Request, components ...templ.Component) {
+	w.Header().Set("Content-Type", "text/event-stream")
+	w.Header().Set("Cache-Control", "no-cache")
+
+	var out strings.Builder
+	out.WriteString("event: datastar-patch-elements\n")
+	for _, c := range components {
+		var html strings.Builder
+		if err := c.Render(r.Context(), &html); err != nil {
+			log.Printf("patch %s: %v", r.URL.Path, err)
+			return
+		}
+		// One `data: elements` line per line of HTML, as the protocol wants.
+		for _, line := range strings.Split(html.String(), "\n") {
+			if strings.TrimSpace(line) == "" {
+				continue
+			}
+			out.WriteString("data: elements ")
+			out.WriteString(line)
+			out.WriteString("\n")
+		}
+	}
+	out.WriteString("\n")
+
+	io.WriteString(w, out.String())
+	if f, ok := w.(http.Flusher); ok {
+		f.Flush()
+	}
+}
+
 // searchBoard re-renders the dish board as the search box is typed into.
 func (a *app) searchBoard(w http.ResponseWriter, r *http.Request) {
 	var signals searchSignals
@@ -300,6 +384,12 @@ func (a *app) quickAdd(w http.ResponseWriter, r *http.Request) {
 			log.Printf("quick add: %v", err)
 			form.Err = "Tallennus epäonnistui."
 		default:
+			// Created: straight on to its sides step.
+			opts := logOptions{Date: date, Dish: strconv.FormatInt(id, 10)}
+			if isDatastar(r) {
+				fragment(w, r, dayList(a.buildLog(r, opts)))
+				return
+			}
 			a.redirectToPick(w, r, date, id)
 			return
 		}
@@ -307,23 +397,12 @@ func (a *app) quickAdd(w http.ResponseWriter, r *http.Request) {
 
 	// Rejected: back to the board with the form filled in and the search
 	// still narrowed, so the add card stays on screen.
-	v := logView{
-		Date:      date,
-		Today:     today(a.loc),
-		Search:    form.Name,
-		Checked:   map[int64]bool{},
-		New:       form,
-		ShowBoard: true,
+	v := a.buildLog(r, logOptions{Date: date, Search: form.Name})
+	v.New = form
+	if isDatastar(r) {
+		fragment(w, r, dayList(v))
+		return
 	}
-	var err error
-	if v.Dishes, err = listDishes(a.db, v.Search); err != nil {
-		log.Printf("list dishes: %v", err)
-	}
-	v.Groups = groupDishes(v.Dishes)
-	if v.Special, err = listSpecial(a.db, v.Search); err != nil {
-		log.Printf("list special: %v", err)
-	}
-	a.loadDays(r, &v)
 	render(w, r, logPage(v))
 }
 
@@ -333,9 +412,7 @@ func (a *app) redirectToPick(w http.ResponseWriter, r *http.Request, date time.T
 	if strings.Contains(target, "?") {
 		sep = "&"
 	}
-	http.Redirect(w, r,
-		target+sep+"ruoka="+strconv.FormatInt(id, 10)+"#"+dayAnchor(date),
-		http.StatusSeeOther)
+	http.Redirect(w, r, target+sep+"ruoka="+strconv.FormatInt(id, 10), http.StatusSeeOther)
 }
 
 // save records the meal and redirects, so a refresh cannot double-post.
@@ -360,7 +437,7 @@ func (a *app) save(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "tallennus epäonnistui", http.StatusInternalServerError)
 		return
 	}
-	a.redirectToDay(w, r, date)
+	a.finishDay(w, r, date)
 }
 
 func (a *app) delete(w http.ResponseWriter, r *http.Request) {
@@ -370,13 +447,12 @@ func (a *app) delete(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "poisto epäonnistui", http.StatusInternalServerError)
 		return
 	}
-	a.redirectToDay(w, r, date)
+	a.finishDay(w, r, date)
 }
 
-// redirectToDay returns to the day in the list, anchor included, so saving or
-// deleting leaves the viewport where the work was happening.
+// redirectToDay is the no-JavaScript path back after a write.
 func (a *app) redirectToDay(w http.ResponseWriter, r *http.Request, date time.Time) {
-	http.Redirect(w, r, dayLink(date, today(a.loc)), http.StatusSeeOther)
+	http.Redirect(w, r, dayURL("/", date, today(a.loc)), http.StatusSeeOther)
 }
 
 // mainForm and sideForm carry what the user typed, so a rejected submission
@@ -410,7 +486,20 @@ type catalogView struct {
 	DeleteKind string
 }
 
+// catalog renders the whole page. show patches the same state in place, so
+// nothing navigates: both build the view the same way.
 func (a *app) catalog(w http.ResponseWriter, r *http.Request) {
+	a.renderCatalog(w, r, a.catalogState(r))
+}
+
+// show is what every catalog link actually calls. It patches the list and both
+// forms rather than loading a page, so opening an edit form or asking to
+// delete a row leaves the scroll position exactly where it was.
+func (a *app) show(w http.ResponseWriter, r *http.Request) {
+	a.patchCatalog(w, r, a.catalogState(r))
+}
+
+func (a *app) catalogState(r *http.Request) catalogView {
 	v := catalogView{
 		Main:   mainForm{Categories: map[string]bool{}, HasSides: true},
 		Search: strings.TrimSpace(r.URL.Query().Get("haku")),
@@ -446,10 +535,11 @@ func (a *app) catalog(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	a.renderCatalog(w, r, v)
+	return v
 }
 
-func (a *app) renderCatalog(w http.ResponseWriter, r *http.Request, v catalogView) {
+// fillCatalog loads the lists into a view built from the request.
+func (a *app) fillCatalog(v *catalogView) {
 	if v.Main.Categories == nil {
 		v.Main.Categories = map[string]bool{}
 	}
@@ -465,9 +555,20 @@ func (a *app) renderCatalog(w http.ResponseWriter, r *http.Request, v catalogVie
 	if v.Sides, err = listSides(a.db, v.Search); err != nil {
 		log.Printf("list sides: %v", err)
 	}
+}
+
+func (a *app) renderCatalog(w http.ResponseWriter, r *http.Request, v catalogView) {
+	a.fillCatalog(&v)
 	render(w, r, catalogPage(v))
 }
 
+// patchCatalog swaps the list and both forms in one event. They move together:
+// opening an edit form also has to clear whatever delete was being confirmed.
+func (a *app) patchCatalog(w http.ResponseWriter, r *http.Request, v catalogView) {
+	a.fillCatalog(&v)
+	patchElements(w, r, catalogList(v), mainForm_(v.Main), sideForm_(v.Side))
+}
+
 // saveMain adds or updates a main dish. A rejected form is re-rendered with
 // the values still in it; a good one redirects, so refresh cannot re-submit.
 func (a *app) saveMain(w http.ResponseWriter, r *http.Request) {
@@ -508,11 +609,28 @@ func (a *app) saveMain(w http.ResponseWriter, r *http.Request) {
 			log.Printf("save main: %v", err)
 			form.Err = "Tallennus epäonnistui."
 		default:
-			http.Redirect(w, r, "/ruoat", http.StatusSeeOther)
+			// Saved: hand back a blank form so it collapses, and a list with
+			// the dish in it.
+			a.finishCatalog(w, r, catalogView{})
 			return
 		}
 	}
-	a.renderCatalog(w, r, catalogView{Main: form})
+	a.finishCatalog(w, r, catalogView{Main: form})
+}
+
+// finishCatalog answers a catalog write: a patch for Datastar, a redirect for
+// a plain form post. Without the redirect, submitting with JavaScript off
+// would leave the browser sitting on a POST it could not reload.
+func (a *app) finishCatalog(w http.ResponseWriter, r *http.Request, v catalogView) {
+	if isDatastar(r) {
+		a.patchCatalog(w, r, v)
+		return
+	}
+	if v.Main.Err != "" || v.Side.Err != "" {
+		a.renderCatalog(w, r, v)
+		return
+	}
+	http.Redirect(w, r, "/ruuat", http.StatusSeeOther)
 }
 
 func (a *app) saveSide(w http.ResponseWriter, r *http.Request) {
@@ -537,11 +655,11 @@ func (a *app) saveSide(w http.ResponseWriter, r *http.Request) {
 			log.Printf("save side: %v", err)
 			form.Err = "Tallennus epäonnistui."
 		default:
-			http.Redirect(w, r, "/ruoat", http.StatusSeeOther)
+			a.finishCatalog(w, r, catalogView{})
 			return
 		}
 	}
-	a.renderCatalog(w, r, catalogView{Side: form})
+	a.finishCatalog(w, r, catalogView{Side: form})
 }
 
 // deleteDish soft-deletes, so log entries keep resolving the name (PRD §6).
@@ -565,7 +683,7 @@ func (a *app) deleteDish(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "poisto epäonnistui", http.StatusInternalServerError)
 		return
 	}
-	http.Redirect(w, r, "/ruoat", http.StatusSeeOther)
+	a.finishCatalog(w, r, catalogView{})
 }
 
 // importDishes takes a bundle either pasted into the textarea or uploaded as a

cmd/foodster/main.go

@@ -35,6 +35,21 @@ var staticFS embed.FS
 // version is replaced at build time with the CalVer tag (see `make image`).
 var version = "dev"
 
+// envTag marks the browser tab of anything that is not production, so a dev
+// instance and the real one open side by side are told apart at a glance.
+// Empty in production, which is the default.
+var envTag string
+
+func setEnvTag(value string) {
+	value = strings.TrimSpace(value)
+	if value == "" || strings.EqualFold(value, "prod") || strings.EqualFold(value, "production") {
+		envTag = ""
+		return
+	}
+	// Whatever it says, so ENV=staging labels itself too.
+	envTag = strings.ToLower(value)
+}
+
 const (
 	listenAddr = ":8080"
 	defaultTZ  = "Europe/Helsinki"
@@ -55,7 +70,7 @@ func run() error {
 		"import a JSON dish bundle (PRD §7.3 shape) and exit")
 	flag.Parse()
 
-	db, err := openDB(cmp.Or(os.Getenv("FOODSTER_DB"), defaultDB))
+	db, err := openDB(cmp.Or(os.Getenv("DB"), defaultDB))
 	if err != nil {
 		return err
 	}
@@ -66,9 +81,9 @@ func run() error {
 		return runImport(db, *importPath)
 	}
 
-	password := os.Getenv("FOODSTER_PASSWORD")
+	password := os.Getenv("PASSWORD")
 	if password == "" {
-		return errors.New("FOODSTER_PASSWORD is not set")
+		return errors.New("PASSWORD is not set")
 	}
 
 	// Fail rather than fall back to UTC: a silently wrong zone shifts logged
@@ -79,9 +94,11 @@ func run() error {
 		return fmt.Errorf("TZ: %w", err)
 	}
 
-	// The container always publishes :8080; FOODSTER_ADDR exists so tests and
-	// a second local instance can pick another port.
-	addr := cmp.Or(os.Getenv("FOODSTER_ADDR"), listenAddr)
+	setEnvTag(os.Getenv("ENV"))
+
+	// The container always publishes :8080; ADDR exists so tests and a second
+	// local instance can pick another port.
+	addr := cmp.Or(os.Getenv("ADDR"), listenAddr)
 
 	srv := &http.Server{
 		Addr:              addr,
@@ -159,9 +176,11 @@ func routes(db *sql.DB, loc *time.Location, password string) http.Handler {
 	mux.HandleFunc("POST /kirjaa", a.save)
 	mux.HandleFunc("POST /lisaa", a.quickAdd)
 	mux.HandleFunc("GET /etsi", a.searchBoard)
+	mux.HandleFunc("GET /paiva", a.day)
 	mux.HandleFunc("POST /poista", a.delete)
 	mux.HandleFunc("GET /ruuat", a.catalog)
 	mux.HandleFunc("GET /ruuat/etsi", a.searchCatalog)
+	mux.HandleFunc("GET /ruuat/nayta", a.show)
 	mux.HandleFunc("POST /ruuat/paaruoka", a.saveMain)
 	mux.HandleFunc("POST /ruuat/lisuke", a.saveSide)
 	mux.HandleFunc("POST /ruuat/poista", a.deleteDish)

cmd/foodster/main_test.go

@@ -105,6 +105,29 @@ func TestReadSignals(t *testing.T) {
 	}
 }
 
+func TestEnvTagMarksNonProduction(t *testing.T) {
+	t.Cleanup(func() { envTag = "" })
+
+	cases := []struct{ env, want string }{
+		// Production is the default and must stay unmarked: the tag exists to
+		// pick the dev tab out of two identical ones.
+		{"", "Foodster"},
+		{"prod", "Foodster"},
+		{"PRODUCTION", "Foodster"},
+		{"  ", "Foodster"},
+		{"dev", "dev · Foodster"},
+		{"DEV", "dev · Foodster"},
+		{"staging", "staging · Foodster"},
+	}
+
+	for _, c := range cases {
+		setEnvTag(c.env)
+		if got := pageTitle("Foodster"); got != c.want {
+			t.Errorf("ENV=%q: title = %q, want %q", c.env, got, c.want)
+		}
+	}
+}
+
 func TestMigrateCreatesSchema(t *testing.T) {
 	db, err := openDB(t.TempDir() + "/test.db")
 	if err != nil {

cmd/foodster/views.templ

@@ -43,16 +43,21 @@ func dayURL(base string, d, now time.Time) string {
 	return base + "?pvm=" + isoDate(d)
 }
 
-// dayAnchor names the element a day expands into.
-func dayAnchor(d time.Time) string {
-	return "paiva-" + isoDate(d)
+// showURL turns a catalog page link into the patch endpoint behind it, so the
+// href and the Datastar call never drift apart.
+func showURL(pageURL string) string {
+	return strings.Replace(pageURL, "/ruuat?", "/ruuat/nayta?", 1)
 }
 
-// dayLink opens a day and lands the viewport on it. Without the fragment the
-// browser would jump to the top of a page whose selected day might be far
-// down the list.
-func dayLink(d, now time.Time) string {
-	return dayURL("/", d, now) + "#" + dayAnchor(d)
+// dayPatch is the endpoint behind every link in the day list. The href beside
+// it stays a real page URL for anyone without JavaScript; Datastar calls this
+// instead and swaps the list where it stands.
+func dayPatch(d time.Time, param string) string {
+	url := "/paiva?pvm=" + isoDate(d)
+	if param != "" {
+		url += "&" + param
+	}
+	return url
 }
 
 // pickSeparator joins a dish onto a day URL, which already carries ?pvm= for
@@ -64,15 +69,14 @@ func pickSeparator(v logView) string {
 	return "&"
 }
 
-// stepURL is any link inside the open day. It keeps the anchor, so picking a
-// dish or cancelling stays where the day is instead of throwing the viewport
-// back to the top of the list.
+// stepURL is the page URL for a link inside the open day: the fallback when
+// there is no JavaScript to intercept it.
 func stepURL(v logView, param string) string {
 	url := dayURL("/", v.Date, v.Today)
 	if param != "" {
 		url += pickSeparator(v) + param
 	}
-	return url + "#" + dayAnchor(v.Date)
+	return url
 }
 
 // jsString renders a Go string as a JavaScript literal, for the data-signals
@@ -104,6 +108,16 @@ func categoryLabels(d Dish) string {
 	return strings.Join(names, ", ")
 }
 
+// pageTitle prefixes the tab title on any instance that is not production.
+// The tab is the only place a browser shows which of two identical apps you
+// are looking at.
+func pageTitle(title string) string {
+	if envTag == "" {
+		return title
+	}
+	return envTag + " · " + title
+}
+
 // countFI renders "1 pääruoka" but "16 pääruokaa": Finnish takes the partitive
 // after every number except one.
 func countFI(n int, one, many string) string {
@@ -126,7 +140,7 @@ templ page(title, current string) {
 			// header rather than butting against it.
 			<meta name="theme-color" media="(prefers-color-scheme: light)" content="#FFFFFF"/>
 			<meta name="theme-color" media="(prefers-color-scheme: dark)" content="#1C1E22"/>
-			<title>{ title }</title>
+			<title>{ pageTitle(title) }</title>
 			<link rel="icon" href="/static/favicon.svg" type="image/svg+xml"/>
 			<link rel="apple-touch-icon" href="/static/apple-touch-icon.png"/>
 			<!-- use-credentials: the manifest is fetched behind Basic auth and
@@ -314,13 +328,13 @@ templ logPage(v logView) {
 // above the list and drop that day out of it, so the rows below jumped up
 // under the tap. Now nothing moves — the row grows.
 templ dayList(v logView) {
-	<section class="history">
+	<section class="history" id="paivat">
 		for i, row := range v.History.Rows {
 			if i == 0 || v.History.Rows[i-1].Date.Month() != row.Date.Month() {
 				<p class="monthrule">{ monthFI(row.Date) }</p>
 			}
 			if row.Date.Equal(v.Date) {
-				<div class="open" id={ dayAnchor(row.Date) }>
+				<div class="open">
 					<p class="openday">
 						if row.Date.Equal(v.Today) {
 							Tänään
@@ -338,7 +352,11 @@ templ dayList(v logView) {
 					}
 				</div>
 			} else if row.Entry != nil {
-				<a class="entry" href={ templ.SafeURL(dayLink(row.Date, v.Today)) }>
+				<a
+					class="entry"
+					href={ templ.SafeURL(dayURL("/", row.Date, v.Today)) }
+					data-on:click__prevent={ "@get('" + dayPatch(row.Date, "") + "')" }
+				>
 					<time>{ dayLabelFI(row.Date) }</time>
 					<div>
 						<div class="nm">
@@ -350,7 +368,11 @@ templ dayList(v logView) {
 					<span class="chev">›</span>
 				</a>
 			} else {
-				<a class="gapline" href={ templ.SafeURL(dayLink(row.Date, v.Today)) }>
+				<a
+					class="gapline"
+					href={ templ.SafeURL(dayURL("/", row.Date, v.Today)) }
+					data-on:click__prevent={ "@get('" + dayPatch(row.Date, "") + "')" }
+				>
 					<time>{ dayLabelFI(row.Date) }</time>
 					<span>Ei merkintää</span>
 					<span class="act">Merkitse</span>
@@ -361,6 +383,7 @@ templ dayList(v logView) {
 			<a
 				class="more"
 				href={ templ.SafeURL(dayURL("/", v.Date, v.Today) + pickSeparator(v) + "paivat=" + strconv.Itoa(v.HistoryMore)) }
+				data-on:click__prevent={ "@get('" + dayPatch(v.Date, "paivat="+strconv.Itoa(v.HistoryMore)) + "')" }
 			>Näytä lisää</a>
 		}
 	</section>
@@ -436,6 +459,7 @@ templ boardList(v logView) {
 					<a
 						class="pill plain"
 						href={ templ.SafeURL(stepURL(v, "ruoka="+strconv.FormatInt(d.ID, 10))) }
+						data-on:click__prevent={ "@get('" + dayPatch(v.Date, "ruoka="+strconv.FormatInt(d.ID, 10)) + "')" }
 					>
 						@categoryIcon(d.CategoryKey())
 						{ d.Name }
@@ -471,7 +495,11 @@ templ quickAddCard(v logView) {
 		if v.New.Err != "" {
 			<p class="formerr">{ v.New.Err }</p>
 		}
-		<form method="post" action="/lisaa">
+		<form
+			method="post"
+			action="/lisaa"
+			data-on:submit__prevent="@post('/lisaa', {contentType: 'form'})"
+		>
 			<input type="hidden" name="pvm" value={ isoDate(v.Date) }/>
 			<label class="field">
 				<span>Nimi</span>
@@ -503,6 +531,7 @@ templ dishPill(d Dish, v logView) {
 	<a
 		class={ "pill", d.Size() }
 		href={ templ.SafeURL(stepURL(v, "ruoka="+strconv.FormatInt(d.ID, 10))) }
+		data-on:click__prevent={ "@get('" + dayPatch(v.Date, "ruoka="+strconv.FormatInt(d.ID, 10)) + "')" }
 	>
 		@categoryIcon(d.CategoryKey())
 		{ d.Name }
@@ -518,7 +547,11 @@ templ sidesStep(v logView) {
 			@categoryIcon(v.Chosen.CategoryKey())
 			{ v.Chosen.Name }
 		</h3>
-		<form method="post" action="/kirjaa">
+		<form
+			method="post"
+			action="/kirjaa"
+			data-on:submit__prevent="@post('/kirjaa', {contentType: 'form'})"
+		>
 			<input type="hidden" name="pvm" value={ isoDate(v.Date) }/>
 			<input type="hidden" name="ruoka" value={ strconv.FormatInt(v.Chosen.ID, 10) }/>
 			if v.Chosen.HasSides && len(v.Sides) > 0 {
@@ -540,7 +573,11 @@ templ sidesStep(v logView) {
 			}
 			<button class="primary" type="submit">Tallenna</button>
 		</form>
-		<a class="ghost" href={ templ.SafeURL(stepURL(v, "")) }>Peruuta</a>
+		<a
+			class="ghost"
+			href={ templ.SafeURL(stepURL(v, "")) }
+			data-on:click__prevent={ "@get('" + dayPatch(v.Date, "") + "')" }
+		>Peruuta</a>
 	</section>
 }
 
@@ -561,21 +598,31 @@ templ loggedCard(v logView) {
 		if v.Confirming {
 			<p class="q">Poistetaanko merkintä?</p>
 			<div class="pair">
-				<form method="post" action="/poista">
+				<form
+					method="post"
+					action="/poista"
+					data-on:submit__prevent="@post('/poista', {contentType: 'form'})"
+				>
 					<input type="hidden" name="pvm" value={ isoDate(v.Date) }/>
 					<button class="btn del" type="submit">Kyllä, poista</button>
 				</form>
-				<a class="btn" href={ templ.SafeURL(stepURL(v, "")) }>Peruuta</a>
+				<a
+					class="btn"
+					href={ templ.SafeURL(stepURL(v, "")) }
+					data-on:click__prevent={ "@get('" + dayPatch(v.Date, "") + "')" }
+				>Peruuta</a>
 			</div>
 		} else {
 			<div class="pair">
 				<a
 					class="btn"
 					href={ templ.SafeURL(stepURL(v, "muuta=1")) }
+					data-on:click__prevent={ "@get('" + dayPatch(v.Date, "muuta=1") + "')" }
 				>Muokkaa</a>
 				<a
 					class="btn del"
 					href={ templ.SafeURL(stepURL(v, "poista=1")) }
+					data-on:click__prevent={ "@get('" + dayPatch(v.Date, "poista=1") + "')" }
 				>Poista</a>
 			</div>
 		}
@@ -689,25 +736,39 @@ templ emptyNote(search string) {
 // rowActions is a pencil and a bin, until the bin is tapped: then the row
 // asks. An icon is a smaller target to hit by accident than a word, and the
 // dish disappears from every picker the moment it goes.
+// Every control here is a real link or form, so the page still works without
+// JavaScript. Datastar intercepts them and patches the list in place instead,
+// which is the whole point: a delete confirmation halfway down a long list
+// must not send the browser back to the top.
 templ rowActions(v catalogView, editURL string, id int64, kind string) {
 	if v.DeleteID == id && v.DeleteKind == kind {
 		<div class="rowactions confirming">
 			<span>Poista?</span>
-			<form method="post" action="/ruuat/poista">
+			<form
+				method="post"
+				action="/ruuat/poista"
+				data-on:submit__prevent="@post('/ruuat/poista', {contentType: 'form'})"
+			>
 				<input type="hidden" name="id" value={ strconv.FormatInt(id, 10) }/>
 				<input type="hidden" name="tyyppi" value={ kind }/>
 				<button type="submit" class="del">Kyllä</button>
 			</form>
-			<a href="/ruuat">Peruuta</a>
+			<a href="/ruuat" data-on:click__prevent="@get('/ruuat/nayta')">Peruuta</a>
 		</div>
 	} else {
 		<div class="rowactions">
-			<a href={ templ.SafeURL(editURL) } aria-label="Muokkaa" title="Muokkaa">
+			<a
+				href={ templ.SafeURL(editURL) }
+				data-on:click__prevent={ "@get('" + showURL(editURL) + "')" }
+				aria-label="Muokkaa"
+				title="Muokkaa"
+			>
 				@iconPencil()
 			</a>
 			<a
 				class="del"
 				href={ templ.SafeURL("/ruuat?poista=" + strconv.FormatInt(id, 10) + "&tyyppi=" + kind) }
+				data-on:click__prevent={ "@get('/ruuat/nayta?poista=" + strconv.FormatInt(id, 10) + "&tyyppi=" + kind + "')" }
 				aria-label="Poista"
 				title="Poista"
 			>
@@ -746,7 +807,11 @@ templ mainForm_(f mainForm) {
 		if f.Err != "" {
 			<p class="formerr">{ f.Err }</p>
 		}
-		<form method="post" action="/ruuat/paaruoka">
+		<form
+			method="post"
+			action="/ruuat/paaruoka"
+			data-on:submit__prevent="@post('/ruuat/paaruoka', {contentType: 'form'})"
+		>
 			if f.ID != 0 {
 				<input type="hidden" name="id" value={ strconv.FormatInt(f.ID, 10) }/>
 			}
@@ -774,7 +839,7 @@ templ mainForm_(f mainForm) {
 			<button class="primary" type="submit">Tallenna</button>
 		</form>
 		if f.ID != 0 {
-			<a class="ghost" href="/ruuat">Peruuta</a>
+			<a class="ghost" href="/ruuat" data-on:click__prevent="@get('/ruuat/nayta')">Peruuta</a>
 		}
 	</details>
 }
@@ -803,7 +868,11 @@ templ sideForm_(f sideForm) {
 		if f.Err != "" {
 			<p class="formerr">{ f.Err }</p>
 		}
-		<form method="post" action="/ruuat/lisuke">
+		<form
+			method="post"
+			action="/ruuat/lisuke"
+			data-on:submit__prevent="@post('/ruuat/lisuke', {contentType: 'form'})"
+		>
 			if f.ID != 0 {
 				<input type="hidden" name="id" value={ strconv.FormatInt(f.ID, 10) }/>
 			}
@@ -814,7 +883,7 @@ templ sideForm_(f sideForm) {
 			<button class="primary" type="submit">Tallenna</button>
 		</form>
 		if f.ID != 0 {
-			<a class="ghost" href="/ruuat">Peruuta</a>
+			<a class="ghost" href="/ruuat" data-on:click__prevent="@get('/ruuat/nayta')">Peruuta</a>
 		}
 	</details>
 }

compose.yaml

@@ -1,19 +1,23 @@
 services:
   app:
-    image: ${FOODSTER_REPO:?set FOODSTER_REPO in .env}:${FOODSTER_TAG:-latest}
+    image: ${REPO:?set REPO in .env}:${TAG:-latest}
     restart: unless-stopped
 
-    # The database is a bind mount, not a named volume: it sits in ./data on
-    # the host where it can be listed, copied and opened with any sqlite
-    # client. The image runs as UID 65534, so the container has to be told
-    # which host user owns that directory.
-    user: "${FOODSTER_UID:-1000}:${FOODSTER_GID:-1000}"
+    # A bind mount rather than a named volume: the database sits in ./data on
+    # the host, where it can be listed, copied and backed up without going
+    # through the container engine. The image runs as UID 65534, so the
+    # container has to be told which host user owns that directory.
+    #
+    # PUID/PGID rather than UID/GID: UID is a read-only variable in bash, so a
+    # value set here would be silently replaced by the invoking shell's own.
+    user: "${PUID:-1000}:${PGID:-1000}"
     volumes:
       - ./data:/data
 
     environment:
-      FOODSTER_PASSWORD: ${FOODSTER_PASSWORD:?set FOODSTER_PASSWORD in .env}
-      FOODSTER_DB: /data/foodster.db
+      PASSWORD: ${PASSWORD:?set PASSWORD in .env}
+      DB: /data/foodster.db
+      ENV: ${ENV:-prod}
       TZ: ${TZ:-Europe/Helsinki}
 
     # No published ports: Traefik reaches the container over the shared
@@ -22,7 +26,7 @@ services:
     labels:
       - traefik.enable=true
       - traefik.http.routers.foodster.entrypoints=websecure
-      - traefik.http.routers.foodster.rule=Host(`${FOODSTER_HOST:?set FOODSTER_HOST in .env}`)
+      - traefik.http.routers.foodster.rule=Host(`${HOST:?set HOST in .env}`)
       - traefik.http.routers.foodster.tls=true
       - traefik.http.services.foodster.loadbalancer.server.port=8080
       - traefik.docker.network=traefik

scripts/smoke.sh

@@ -16,7 +16,7 @@ trap 'kill ${srv:-0} 2>/dev/null || true; rm -rf "$tmp"' EXIT
 
 go build -o "$tmp/foodster" ./cmd/foodster
 
-FOODSTER_PASSWORD="$pass" FOODSTER_DB="$tmp/smoke.db" FOODSTER_ADDR="$addr" \
+PASSWORD="$pass" DB="$tmp/smoke.db" ADDR="$addr" \
 	"$tmp/foodster" >"$tmp/server.log" 2>&1 &
 srv=$!
 
@@ -72,6 +72,8 @@ check "theme script is served" \
 
 home=$(curl -s -u ":$pass" "http://$addr/")
 check "the header carries the brand" "$home" "Foodster"
+# ENV is unset here, so this instance is production and unmarked.
+check "production tabs are not tagged" "$home" "<title>Foodster</title>"
 check "dark is the default without JavaScript" "$home" '<html lang="fi" data-theme="dark">'
 check "the theme toggle is present" "$home" "data-theme-toggle"
 check "both theme icons ship so CSS can pick one" "$home" 'class="i-moon"'
@@ -140,13 +142,31 @@ check "the saved day shows what was eaten" \
 # The selected day expands inside the list rather than in a panel above it,
 # so the rows below do not shift when one is tapped.
 day=$(curl -s -u ":$pass" "http://$addr/?pvm=2026-09-05")
-check "the selected day expands in place" "$day" 'id="paiva-2026-09-05"'
+check "the selected day expands in place" "$day" 'class="open"'
 check "and stays in the list rather than being lifted out" "$day" "kirjattu"
-check "links inside it keep the anchor" "$day" "#paiva-2026-09-05"
 
-check "saving returns to the day, not the top" \
+# ---- the day list patches in place instead of navigating ----------------
+
+dayp=$(curl -s -u ":$pass" -H 'Datastar-Request: true' "http://$addr/paiva?pvm=2026-09-05")
+check "opening a day patches the list" "$dayp" 'id="paivat"'
+refute "and returns a fragment, not a page" "$dayp" "<html"
+
+check "picking a dish patches to the sides step" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+		"http://$addr/paiva?pvm=2026-09-05&ruoka=$ruoka")" "Tallenna"
+
+check "saving from Datastar patches back" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+		-d "pvm=2026-09-04&ruoka=$ruoka" "http://$addr/kirjaa")" 'id="paivat"'
+
+check "deleting from Datastar patches back" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+		-d "pvm=2026-09-04" "http://$addr/poista")" 'id="paivat"'
+
+# Without the header it must still redirect, for no JavaScript.
+check "a plain save still redirects to the day" \
 	"$(curl -s -o /dev/null -w '%{redirect_url}' -u ":$pass" \
-		-d "pvm=2026-09-04&ruoka=$ruoka" "http://$addr/kirjaa")" "#paiva-2026-09-04"
+		-d "pvm=2026-09-04&ruoka=$ruoka" "http://$addr/kirjaa")" "pvm=2026-09-04"
 
 # Deleting a logged meal drops the row outright, so it asks first.
 saved=$(curl -s -u ":$pass" "http://$addr/?pvm=2026-09-05&poista=1")
@@ -220,9 +240,12 @@ check "the quick-added dish is on the board" \
 
 # ---- catalog CRUD from the UI -------------------------------------------
 
-check "adding a main redirects" \
-	"$(curl -s -o /dev/null -w '%{http_code}' -u ":$pass" \
-		-d 'nimi=uunikala&kategoria=fish&lisukkeita=1' "http://$addr/ruuat/paaruoka")" "303"
+# Assert where it redirects, not just that it does: these pointed at the old
+# /ruoat spelling for a while and every 303-only check was happy.
+check "adding a main redirects back to the catalog" \
+	"$(curl -s -o /dev/null -w '%{redirect_url}' -u ":$pass" \
+		-d 'nimi=uunikala&kategoria=fish&lisukkeita=1' "http://$addr/ruuat/paaruoka")" \
+	"/ruuat"
 
 catalog=$(curl -s -u ":$pass" "http://$addr/ruuat")
 check "the new main is listed, sentence-cased" "$catalog" "Uunikala"
@@ -239,9 +262,10 @@ check "a nameless dish is refused" \
 	"$(curl -s -u ":$pass" -d 'nimi=+++&kategoria=fish' "http://$addr/ruuat/paaruoka")" \
 	"Anna nimi."
 
-check "adding a side redirects" \
-	"$(curl -s -o /dev/null -w '%{http_code}' -u ":$pass" \
-		-d 'nimi=lohkoperunat' "http://$addr/ruuat/lisuke")" "303"
+check "adding a side redirects back to the catalog" \
+	"$(curl -s -o /dev/null -w '%{redirect_url}' -u ":$pass" \
+		-d 'nimi=lohkoperunat' "http://$addr/ruuat/lisuke")" \
+	"/ruuat"
 
 check "the new side is listed" \
 	"$(curl -s -u ":$pass" "http://$addr/ruuat")" "Lohkoperunat"
@@ -264,9 +288,35 @@ check "the bin asks before deleting" \
 check "the dish is still there while it asks" \
 	"$(curl -s -u ":$pass" "http://$addr/ruuat?poista=$uusi&tyyppi=paa")" "Uunikala"
 
-check "confirming the delete redirects" \
-	"$(curl -s -o /dev/null -w '%{http_code}' -u ":$pass" \
-		-d "id=$uusi&tyyppi=paa" "http://$addr/ruuat/poista")" "303"
+# ---- the catalog patches in place instead of navigating -----------------
+
+# A delete confirmation halfway down a long list must not send the browser
+# back to the top, so these answer with a Datastar patch rather than a page.
+patch=$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+	"http://$addr/ruuat/nayta?poista=$uusi&tyyppi=paa")
+check "asking to delete patches rather than navigates" "$patch" "event: datastar-patch-elements"
+check "the patch carries the list" "$patch" 'id="ruokalista"'
+check "and both forms, so an open one closes" "$patch" 'id="paaruoka"'
+check "the row it patches in is asking" "$patch" "Poista?"
+
+check "patches are served as an event stream" \
+	"$(curl -s -o /dev/null -w '%{content_type}' -u ":$pass" -H 'Datastar-Request: true' \
+		"http://$addr/ruuat/nayta")" "text/event-stream"
+
+check "deleting from Datastar patches too" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' \
+		-d "id=$uusi&tyyppi=paa" "http://$addr/ruuat/poista")" \
+	"event: datastar-patch-elements"
+
+refute "and the dish is gone from the patched list" \
+	"$(curl -s -u ":$pass" -H 'Datastar-Request: true' "http://$addr/ruuat/nayta")" \
+	"Uunikala"
+
+# Without the header it must still be an ordinary redirect, for no JavaScript.
+check "a plain form post still redirects" \
+	"$(curl -s -o /dev/null -w '%{redirect_url}' -u ":$pass" \
+		-d 'nimi=Testiruoka&kategoria=fish' "http://$addr/ruuat/paaruoka")" \
+	"/ruuat"
 
 refute "the dish is gone once confirmed" \
 	"$(curl -s -u ":$pass" "http://$addr/ruuat")" "Uunikala"