refactor(provision)!: suffix the start scale pair _on_start

docs/architecture/README.md

@@ -25,7 +25,7 @@ Declarative architecture docs (English, present tense). These describe the syste
 | Command surface | Two commands, `site` and `bench`, named for the situation rather than for the tool's internal steps; they differ in one thing, the memory tuning, which only `site` applies |
 | Archive read access | `ALTER DEFAULT PRIVILEGES FOR ROLE scada_writer` set **before** `public.trends` is created, and before the writer first runs. The `semiplot_*` tables are granted table by table instead, since the superuser creates them |
 | Objects we add | `semiplot_tags`, `semiplot_groups`, `semiplot_pen_groups`, `semiplot_meta`, the `semiplot_register_new_pens()` function the viewer calls, and the vendor-shaped `public.trends` — no triggers, scheduled jobs, extensions, or other functions; `messages` is not created, the SCADA makes it |
-| SemiPlot schema version | `semiplot_meta.schema_version`, `1` in this release, written by `provision` alone. A floor, not an equality: a viewer refuses a database below the version it needs and accepts one above, because the versions this repository issues grow by addition. |
+| SemiPlot schema version | `semiplot_meta.schema_version`, `1` in this release, written by `provision` alone. A floor, not an equality: a viewer refuses a database below the version it needs and accepts one above, because the versions this repository issues grow by addition. The rule starts with the first installation: until then a schema change, a rename included, edits the `CREATE TABLE` alone and keeps `1`. |
 | Archive schema | Owned by Simple-Scada 2 and documented in the SemiPlot repository. This tool creates `public.trends` once, with the vendor's shape, connected as `scada_writer`, and never alters it afterwards; day partitions and every later change to the schema remain the vendor's |
 | Distribution | Binaries as GitHub release assets; the Linux binary also as `ghcr.io/semiteq/semibase`, `FROM scratch`, one file, pushed after the release exists; benches track `:latest` and a prerelease never moves it |
 | Backup method | `UNDECIDED` — commissioning-time, needs the customer's archive size |

docs/architecture/provisioning.md

@@ -183,7 +183,7 @@ saves a pen through the same connection it reads history on, and a bug in it can
 A `semiplot_tags` row is keyed by `id`, the SCADA variable number. SemiPlot owns the settings in the
 row and none of the keys: its editor changes a pen and never adds one, deletes one or moves one onto
 another variable. The grant on that table is therefore column-level,
-`GRANT SELECT, UPDATE (name, unit, format, color, line_style, enabled_on_start, scale_min, scale_max)`,
+`GRANT SELECT, UPDATE (name, unit, format, color, line_style, enabled_on_start, scale_min_on_start, scale_max_on_start)`,
 and a table-level `UPDATE` would not do: it would let `UPDATE semiplot_tags SET id = ...` re-key a
 pen. A column grant is not a table grant, so `has_table_privilege('semiplot', 'semiplot_tags',
 'UPDATE')` answers false, and no check asks it. A pen row is added only by
@@ -235,7 +235,7 @@ checks a `LANGUAGE sql` body against the relations it names when the function is
 
 | Table | Holds |
 | --- | --- |
-| `semiplot_tags` | One pen: `id` matching `trends.id`, `name`, `unit`, `format` as a .NET numeric format string the viewer applies and the server does not validate, `color` as `#RRGGBB`, `line_style` (0 interpolated, 1 stepped), `enabled_on_start`, and the `scale_min`/`scale_max` pair that bounds the pen's own Y axis. Both bounds `NULL` means autoscale |
+| `semiplot_tags` | One pen: `id` matching `trends.id`, `name`, `unit`, `format` as a .NET numeric format string the viewer applies and the server does not validate, `color` as `#RRGGBB`, `line_style` (0 interpolated, 1 stepped), `enabled_on_start`, and the `scale_min_on_start`/`scale_max_on_start` pair that bounds the pen's own Y axis. Both bounds `NULL` means autoscale. A column with the `_on_start` suffix holds a start value: what the pen opens with in a new window and what the viewer's "Restore initial scale" returns to. Editing the pen on the chart changes the current view and never a start value, and a changed start value never changes a chart already open. Every other settings column is a live setting, which a running chart applies at its next catalogue read |
 | `semiplot_groups` | A group name. `GENERATED ALWAYS AS IDENTITY` rather than `serial`, so `semiplot` needs no `USAGE` on a sequence to insert one |
 | `semiplot_pen_groups` | Membership, `(pen_id, group_id)`. A pen may sit in several groups and in none: a pen with no row here is legal and the viewer shows it ungrouped |
 | `semiplot_meta` | One row: `schema_version`. A `singleton boolean PRIMARY KEY DEFAULT true CHECK (singleton)` admits no second row, and the value is written by one `INSERT ... ON CONFLICT (singleton) DO UPDATE`, so a failure cannot leave the table empty and a re-run cannot leave two rows |
@@ -318,7 +318,9 @@ inside the `semiplot` role's 30 s `statement_timeout` either way.
 This release writes `1`. A viewer states the minimum version it needs and refuses a database
 storing a **lower** one; a **higher** one is accepted, because the versions this repository issues
 grow by addition and a database carrying more than a viewer needs still carries what it needs.
-When `semiplot_markers` arrives it bumps the number to 2, and a viewer that reads only the pen
+The rule starts with the first installation. Until a site runs a provisioned database, a schema
+change, a column rename included, edits the `CREATE TABLE` alone, issues no `ALTER`, and leaves the
+number at `1`. When `semiplot_markers` arrives it bumps the number to 2, and a viewer that reads only the pen
 tables has to keep working against it, which an equality check would break.
 
 A removal is not signalled by this number. An older viewer meeting a dropped column gets 42703,

docs/deployment.md

@@ -70,7 +70,7 @@ SemiBase разворачивается одной утилитой — `semibas
 не может — эту проверку утилита выполняет на каждом запуске.
 
 Строка `semiplot_tags` привязана к номеру переменной SCADA. SemiPlot меняет в ней только
-настройки пера: имя, единицы, формат, цвет, стиль линии, показ при старте и границы шкалы.
+настройки пера: имя, единицы, формат, цвет, стиль линии, показ при старте и начальные границы шкалы.
 Добавить перо напрямую, удалить его или сменить ему `id` роль не может, и утилита на каждом запуске
 проверяет, что эти три команды ей запрещены. Новые перья добавляет только функция
 `semiplot_register_new_pens()`, и только для переменных, которые SCADA уже записала в `trends`.
@@ -98,7 +98,7 @@ DDL. Права `CREATE` в схеме `public` у роли `semiplot` нет 
 
 | Таблица               | Что хранит                                                                                  |
 | --------------------- | ------------------------------------------------------------------------------------------- |
-| `semiplot_tags`       | Перо: `id` из `trends`, имя, единицы, формат числа, цвет `#RRGGBB`, стиль линии, показ при старте, границы шкалы |
+| `semiplot_tags`       | Перо: `id` из `trends`, имя, единицы, формат числа, цвет `#RRGGBB`, стиль линии, показ при старте, начальные границы шкалы |
 | `semiplot_groups`     | Имена групп перьев                                                                            |
 | `semiplot_pen_groups` | Принадлежность пера группам. Перо может входить в несколько групп и ни в одну                 |
 | `semiplot_meta`       | Одну строку: версию схемы                                                                     |

internal/provision/check_test.go

@@ -36,8 +36,8 @@ func TestPlotWriteProbesCoverTheWritableTables(t *testing.T) {
 
 func TestPlotTagsUpdateProbeWritesEverySettingsColumn(t *testing.T) {
 	want := "UPDATE semiplot_tags SET name = name, unit = unit, format = format, color = color, " +
-		"line_style = line_style, enabled_on_start = enabled_on_start, scale_min = scale_min, " +
-		"scale_max = scale_max WHERE id = -1"
+		"line_style = line_style, enabled_on_start = enabled_on_start, " +
+		"scale_min_on_start = scale_min_on_start, scale_max_on_start = scale_max_on_start WHERE id = -1"
 	probes := plotWriteProbes()
 	if got := probes[probePosition(t, probes, "semiplot_tags", "UPDATE")].statement; got != want {
 		t.Errorf("the semiplot_tags probe is %q, want %q", got, want)
@@ -92,8 +92,8 @@ func TestWriteProbeFailure(t *testing.T) {
 	}
 
 	tags := writeProbeFailure(plotWriteProbe{"semiplot_tags", "UPDATE", ""}, errors.New("permission denied"))
-	wantTags := "GRANT SELECT, UPDATE (name, unit, format, color, line_style, enabled_on_start, scale_min, " +
-		"scale_max) ON semiplot_tags TO semiplot"
+	wantTags := "GRANT SELECT, UPDATE (name, unit, format, color, line_style, enabled_on_start, " +
+		"scale_min_on_start, scale_max_on_start) ON semiplot_tags TO semiplot"
 	if !strings.Contains(tags.Error(), wantTags) {
 		t.Errorf("the semiplot_tags repair does not prescribe the column grant: %q", tags)
 	}

internal/provision/schema.go

@@ -26,8 +26,8 @@ var plotEditableTagColumns = []string{
 	"color",
 	"line_style",
 	"enabled_on_start",
-	"scale_min",
-	"scale_max",
+	"scale_min_on_start",
+	"scale_max_on_start",
 }
 
 const (

internal/provision/schema_test.go

@@ -69,8 +69,8 @@ func TestSemiplotTagsColumns(t *testing.T) {
 		"color",
 		"line_style",
 		"enabled_on_start",
-		"scale_min",
-		"scale_max",
+		"scale_min_on_start",
+		"scale_max_on_start",
 	}
 	got := columnNamesOf(semibase.SemiplotTagsSQL)
 	if len(got) != len(want) {
@@ -150,7 +150,7 @@ func TestSemiplotGrantStatements(t *testing.T) {
 		statement string
 	}{
 		{"semiplot_tags", "GRANT SELECT, UPDATE (name, unit, format, color, line_style, enabled_on_start, " +
-			"scale_min, scale_max) ON semiplot_tags TO semiplot"},
+			"scale_min_on_start, scale_max_on_start) ON semiplot_tags TO semiplot"},
 		{"semiplot_groups", "GRANT SELECT, INSERT, UPDATE, DELETE ON semiplot_groups TO semiplot"},
 		{"semiplot_pen_groups", "GRANT SELECT, INSERT, UPDATE, DELETE ON semiplot_pen_groups TO semiplot"},
 		{"semiplot_meta", "GRANT SELECT ON semiplot_meta TO semiplot"},

sql/semiplot_tags.sql

@@ -1,17 +1,17 @@
 -- docs/architecture/provisioning.md#the-semiplot-configuration-schema
 
 CREATE TABLE IF NOT EXISTS semiplot_tags (
-	id               integer PRIMARY KEY,
-	name             text    NOT NULL,
-	unit             text,
-	format           text,
-	color            text,
-	line_style       smallint NOT NULL DEFAULT 0,
-	enabled_on_start boolean  NOT NULL DEFAULT true,
-	scale_min        double precision,
-	scale_max        double precision,
+	id                 integer PRIMARY KEY,
+	name               text    NOT NULL,
+	unit               text,
+	format             text,
+	color              text,
+	line_style         smallint NOT NULL DEFAULT 0,
+	enabled_on_start   boolean  NOT NULL DEFAULT true,
+	scale_min_on_start double precision,
+	scale_max_on_start double precision,
 	CONSTRAINT semiplot_tags_scale_paired CHECK (
-		(scale_min IS NULL) = (scale_max IS NULL)
-		AND (scale_min IS NULL OR scale_min < scale_max)),
+		(scale_min_on_start IS NULL) = (scale_max_on_start IS NULL)
+		AND (scale_min_on_start IS NULL OR scale_min_on_start < scale_max_on_start)),
 	CONSTRAINT semiplot_tags_color_hex CHECK (color IS NULL OR color ~ '^#[0-9A-Fa-f]{6}$')
 );