Hold a joining module at the build it ran, own its directories by its own group, and take a library only when its act is done (hq ADR 0328 review, ADR 0334)

A held module is composed exactly as before it joined, at the build its machine runs, so its port, resources and
contributions stay. A joining module's directories belong to its user and its own group, and its tools' directories
are refused closed to that group; the runner joins it where the engine can say so. A take records the root and is
taken only when the engine states the act done. Libraries' paths and verdicts count modules pulled in by a
requirement, and a unit takes the identity.

internal/inventory/libraries.go

@@ -179,13 +179,17 @@ func (i *Inventory) LibraryNamed(ctx context.Context, module string) error {
 	return nil
 }
 
-// LibraryPaths is every sub-path a module assigned anywhere asks of each library (§6): what its home keeps.
+// LibraryPaths is every sub-path a module on any machine asks of each library (§6): what its home keeps. A module on a
+// machine is one assigned there or one a requirement pulled in — what the machine was last sent.
 func (i *Inventory) LibraryPaths(ctx context.Context) (map[string][]string, error) {
 	shelf, err := i.Catalogue(ctx)
 	if err != nil {
 		return nil, err
 	}
-	rows, err := i.store.Pool().Query(ctx, `select distinct module from assignment`)
+	// Every module assigned anywhere, and every module a machine was last sent — those a requirement pulled in too.
+	rows, err := i.store.Pool().Query(ctx,
+		`select module from assignment
+		 union select jsonb_object_keys(sent_builds) from node where sent_builds is not null and jsonb_typeof(sent_builds) = 'object'`)
 	if err != nil {
 		return nil, err
 	}
@@ -219,17 +223,20 @@ func (i *Inventory) LibraryPaths(ctx context.Context) (map[string][]string, erro
 type TakenLibrary struct {
 	Library string
 	Home    string
+	Root    string
 	Placed  string
 	By      string
 	Ask     string
 	Warrant string
 	Said    string
+	// Done is whether the engine stated the take's act done: only then is the library taken.
+	Done bool
 }
 
-// TakenLibraries is every library taken, by name.
+// TakenLibraries is every library whose take was started, by name; Done says it is taken.
 func (i *Inventory) TakenLibraries(ctx context.Context) (map[string]TakenLibrary, error) {
 	rows, err := i.store.Pool().Query(ctx,
-		`select library, home, placed, taken_by, ask, warrant, said from kept_library`)
+		`select library, home, root, placed, taken_by, ask, warrant, said, done from kept_library`)
 	if err != nil {
 		return nil, err
 	}
@@ -237,7 +244,7 @@ func (i *Inventory) TakenLibraries(ctx context.Context) (map[string]TakenLibrary
 	out := map[string]TakenLibrary{}
 	for rows.Next() {
 		var t TakenLibrary
-		if err := rows.Scan(&t.Library, &t.Home, &t.Placed, &t.By, &t.Ask, &t.Warrant, &t.Said); err != nil {
+		if err := rows.Scan(&t.Library, &t.Home, &t.Root, &t.Placed, &t.By, &t.Ask, &t.Warrant, &t.Said, &t.Done); err != nil {
 			return nil, err
 		}
 		out[t.Library] = t
@@ -245,23 +252,41 @@ func (i *Inventory) TakenLibraries(ctx context.Context) (map[string]TakenLibrary
 	return out, rows.Err()
 }
 
-// RecordTaken keeps that a library was taken on its home, under the operator's warrant. Once per home and filesystem:
-// a second take of the same keeps the first, and one on another home or filesystem (it moved, and the operator was
-// asked again) replaces it.
-func (i *Inventory) RecordTaken(ctx context.Context, t TakenLibrary) error {
+// RecordTakeStarted keeps that a take of a library was started on its home, under the operator's warrant: the
+// engine said it began. The library is taken only once the engine states the act done (TakeDone). Once per home, root
+// and filesystem: a second start of the same keeps the first, and one on another (it moved, and the operator was asked
+// again) replaces it, not done.
+func (i *Inventory) RecordTakeStarted(ctx context.Context, t TakenLibrary) error {
 	switch {
-	case t.Library == "" || t.Home == "":
-		return errors.New("a taken library names itself and its home")
+	case t.Library == "" || t.Home == "" || !strings.HasPrefix(t.Root, "/"):
+		return errors.New("a taken library names itself, its home and its root")
 	case strings.TrimSpace(t.Warrant) == "" || strings.TrimSpace(t.Ask) == "":
 		return errors.New("a library is taken only on the operator's warrant, and this names none")
 	}
 	_, err := i.store.Pool().Exec(ctx,
-		`insert into kept_library (library, home, placed, taken_by, ask, warrant, said)
-		 values ($1, $2, $3, $4, $5, $6, $7)
+		`insert into kept_library (library, home, root, placed, taken_by, ask, warrant, said, done)
+		 values ($1, $2, $3, $4, $5, $6, $7, $8, false)
 		 on conflict (library) do update
-		   set home = excluded.home, placed = excluded.placed, taken_at = now(), taken_by = excluded.taken_by,
-		       ask = excluded.ask, warrant = excluded.warrant, said = excluded.said
-		 where kept_library.home <> excluded.home or kept_library.placed <> excluded.placed`,
-		t.Library, t.Home, t.Placed, t.By, t.Ask, t.Warrant, t.Said)
+		   set home = excluded.home, root = excluded.root, placed = excluded.placed, taken_at = now(),
+		       taken_by = excluded.taken_by, ask = excluded.ask, warrant = excluded.warrant, said = excluded.said,
+		       done = false
+		 where kept_library.home <> excluded.home or kept_library.root <> excluded.root
+		    or kept_library.placed <> excluded.placed`,
+		t.Library, t.Home, t.Root, t.Placed, t.By, t.Ask, t.Warrant, t.Said)
+	return err
+}
+
+// TakeDone keeps that the engine stated a library's take done under a warrant: the library is taken. A warrant the
+// recorded take was not started under changes nothing.
+func (i *Inventory) TakeDone(ctx context.Context, library, warrant string) error {
+	_, err := i.store.Pool().Exec(ctx,
+		`update kept_library set done = true where library = $1 and warrant = $2 and not done`, library, warrant)
+	return err
+}
+
+// TakeFailed forgets a take the engine stated failed under a warrant, never one done: the library is asked about again.
+func (i *Inventory) TakeFailed(ctx context.Context, library, warrant string) error {
+	_, err := i.store.Pool().Exec(ctx,
+		`delete from kept_library where library = $1 and warrant = $2 and not done`, library, warrant)
 	return err
 }