| 1 | package slides |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "testing" |
| 7 | ) |
| 8 | |
| 9 | // TestSettingsRowAndDocumentChangeTogether is the regression test for a |
| 10 | // real bug: saveDeckSettings used to write the document via editDeck |
| 11 | // and then the decks row via a second, separate Updates call — two |
| 12 | // transactions, so a failure between them left the row's title/theme |
| 13 | // diverged from what the document's own meta said. |
| 14 | // |
| 15 | // The fix folds the row write into applyOps' one transaction via |
| 16 | // editDeck's rowUpdates: it lands in the same Updates call the seq |
| 17 | // bump already makes, under the same `WHERE id = ? AND seq = ?` lock, |
| 18 | // so it commits or rolls back with the update-log insert. This proves |
| 19 | // the "or rolls back" half by making the row write fail (an unknown |
| 20 | // column — the particular reason doesn't matter, only that it is a |
| 21 | // failure applyOps' transaction sees) and checking that BOTH the row |
| 22 | // and the document come out unchanged, seq included. |
| 23 | func TestSettingsRowAndDocumentChangeTogether(t *testing.T) { |
| 24 | d := testDB(t) |
| 25 | a, _, err := newApp(d, Config{Env: EnvDevelopment, Logger: quietLogger()}) |
| 26 | if err != nil { |
| 27 | t.Fatalf("newApp: %v", err) |
| 28 | } |
| 29 | t.Cleanup(func() { a.Close() }) |
| 30 | ctx := context.Background() |
| 31 | |
| 32 | owner, _, err := ensureUser(ctx, d.G, "paul@example.test") |
| 33 | if err != nil { |
| 34 | t.Fatalf("ensureUser: %v", err) |
| 35 | } |
| 36 | |
| 37 | row, err := a.createDeckRow(ctx, owner, "Original title", defaultTheme) |
| 38 | if err != nil { |
| 39 | t.Fatalf("createDeckRow: %v", err) |
| 40 | } |
| 41 | ops, err := openingOps("Original title", defaultTheme) |
| 42 | if err != nil { |
| 43 | t.Fatalf("openingOps: %v", err) |
| 44 | } |
| 45 | if err := a.editDeck(ctx, &row, actorFor(owner), ops, nil); err != nil { |
| 46 | t.Fatalf("seed editDeck: %v", err) |
| 47 | } |
| 48 | seqBefore := row.Seq |
| 49 | |
| 50 | renameOps, err := opsJSON([]op{{"op": "set_meta", "title": "New title", "theme": defaultTheme}}) |
| 51 | if err != nil { |
| 52 | t.Fatalf("opsJSON: %v", err) |
| 53 | } |
| 54 | // No column named this, so the Updates call inside applyOps' own |
| 55 | // transaction fails — the row write, not h.Ops, is what breaks. |
| 56 | badRowUpdates := map[string]any{"no_such_column": "boom"} |
| 57 | if err := a.editDeck(ctx, &row, actorFor(owner), renameOps, badRowUpdates); err == nil { |
| 58 | t.Fatal("editDeck with an invalid row update returned no error") |
| 59 | } |
| 60 | |
| 61 | var reloaded Deck |
| 62 | if err := d.G.First(&reloaded, row.ID).Error; err != nil { |
| 63 | t.Fatalf("reload deck row: %v", err) |
| 64 | } |
| 65 | if reloaded.Title != "Original title" { |
| 66 | t.Errorf("deck row title = %q after a failed settings write, want %q (unchanged)", reloaded.Title, "Original title") |
| 67 | } |
| 68 | if reloaded.Seq != seqBefore { |
| 69 | t.Errorf("deck row seq = %d after a failed settings write, want %d (unchanged)", reloaded.Seq, seqBefore) |
| 70 | } |
| 71 | |
| 72 | h, view, err := a.openDeck(ctx, reloaded) |
| 73 | if err != nil { |
| 74 | t.Fatalf("openDeck: %v", err) |
| 75 | } |
| 76 | defer h.Close(ctx) |
| 77 | if view.Meta.Title != "Original title" { |
| 78 | t.Errorf("document meta title = %q after a failed settings write, want %q (unchanged)", view.Meta.Title, "Original title") |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | // TestConcurrentWritersConflictThenRetry is the regression test for a |
| 83 | // 500 where docs/api.md promises a 409. |
| 84 | // |
| 85 | // applyOps' optimistic lock reads as the `WHERE id = ? AND seq = ?` |
| 86 | // bump, and that clause is genuinely a lock — but it is not what a |
| 87 | // losing writer hits FIRST. The update row goes in before the bump, |
| 88 | // under the (deck_id, seq) unique index, and rastrillo's db.Open sets |
| 89 | // GORM's TranslateError, so the loser came out of the INSERT holding a |
| 90 | // wrapped gorm.ErrDuplicatedKey and never reached the clause that |
| 91 | // would have said errDeckBusy. editDeck's one retry and the API's 409 |
| 92 | // both hang off errDeckBusy, so in practice neither existed. |
| 93 | // |
| 94 | // Two handles opened on one deck at one seq is that race exactly, with |
| 95 | // no goroutine and no sleep: the second apply must report the deck |
| 96 | // moved, and editDeck from the stale row must land on its retry. |
| 97 | func TestConcurrentWritersConflictThenRetry(t *testing.T) { |
| 98 | d := testDB(t) |
| 99 | a, _, err := newApp(d, Config{Env: EnvDevelopment, Logger: quietLogger()}) |
| 100 | if err != nil { |
| 101 | t.Fatalf("newApp: %v", err) |
| 102 | } |
| 103 | t.Cleanup(func() { a.Close() }) |
| 104 | ctx := context.Background() |
| 105 | |
| 106 | owner, _, err := ensureUser(ctx, d.G, "paul@example.test") |
| 107 | if err != nil { |
| 108 | t.Fatalf("ensureUser: %v", err) |
| 109 | } |
| 110 | row, err := a.createDeckRow(ctx, owner, "Two writers", defaultTheme) |
| 111 | if err != nil { |
| 112 | t.Fatalf("createDeckRow: %v", err) |
| 113 | } |
| 114 | opening, err := openingOps("Two writers", defaultTheme) |
| 115 | if err != nil { |
| 116 | t.Fatalf("openingOps: %v", err) |
| 117 | } |
| 118 | if err := a.editDeck(ctx, &row, actorFor(owner), opening, nil); err != nil { |
| 119 | t.Fatalf("seed editDeck: %v", err) |
| 120 | } |
| 121 | |
| 122 | // Two copies of the row at one seq: two requests that each read the |
| 123 | // deck before either of them wrote to it. |
| 124 | first, second := row, row |
| 125 | |
| 126 | h1, _, err := a.openDeck(ctx, first) |
| 127 | if err != nil { |
| 128 | t.Fatalf("openDeck (first): %v", err) |
| 129 | } |
| 130 | defer h1.Close(ctx) |
| 131 | h2, _, err := a.openDeck(ctx, second) |
| 132 | if err != nil { |
| 133 | t.Fatalf("openDeck (second): %v", err) |
| 134 | } |
| 135 | defer h2.Close(ctx) |
| 136 | |
| 137 | firstOps, err := opsJSON([]op{{"op": "set_meta", "title": "First writer"}}) |
| 138 | if err != nil { |
| 139 | t.Fatalf("opsJSON: %v", err) |
| 140 | } |
| 141 | secondOps, err := opsJSON([]op{{"op": "set_meta", "title": "Second writer"}}) |
| 142 | if err != nil { |
| 143 | t.Fatalf("opsJSON: %v", err) |
| 144 | } |
| 145 | |
| 146 | if _, err := a.applyOps(ctx, h1, &first, actorFor(owner), firstOps, nil); err != nil { |
| 147 | t.Fatalf("the first writer failed: %v", err) |
| 148 | } |
| 149 | _, err = a.applyOps(ctx, h2, &second, actorFor(owner), secondOps, nil) |
| 150 | if !errors.Is(err, errDeckBusy) { |
| 151 | t.Fatalf("the second writer got %v, want errDeckBusy", err) |
| 152 | } |
| 153 | |
| 154 | // The losing request's own next move: editDeck reopens, replays the |
| 155 | // batch against the state that beat it, and lands. |
| 156 | stale := second |
| 157 | if err := a.editDeck(ctx, &stale, actorFor(owner), secondOps, nil); err != nil { |
| 158 | t.Fatalf("editDeck did not recover from the conflict: %v", err) |
| 159 | } |
| 160 | |
| 161 | var reloaded Deck |
| 162 | if err := d.G.First(&reloaded, row.ID).Error; err != nil { |
| 163 | t.Fatalf("reload deck row: %v", err) |
| 164 | } |
| 165 | if reloaded.Seq != 3 { |
| 166 | t.Errorf("deck row seq = %d after three landed batches, want 3", reloaded.Seq) |
| 167 | } |
| 168 | h, view, err := a.openDeck(ctx, reloaded) |
| 169 | if err != nil { |
| 170 | t.Fatalf("openDeck: %v", err) |
| 171 | } |
| 172 | defer h.Close(ctx) |
| 173 | if view.Meta.Title != "Second writer" { |
| 174 | t.Errorf("document meta title = %q, want %q", view.Meta.Title, "Second writer") |
| 175 | } |
| 176 | } |
| 177 | |
amadan