fix(web): do not retry plugin requests that got an HTTP answer

PluginAPI.request wrapped everything that was not a structured error as
NETWORK_ERROR: a proxy's 502 HTML page (response.json() throws) and a
JSON error without error_code included. Check & Update All retries
NETWORK_ERROR, so those updates were re-sent five more times with
backoff, contrary to the #587 contract that an HTTP error response is
the server's answer.

NETWORK_ERROR now means only that fetch() rejected. Any HTTP response
without an error_code, or with a body that is not JSON, is API_ERROR
with the HTTP status attached. Tested against the shipped api_client.js.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

test/js/README.md

@@ -35,7 +35,7 @@ nothing is listening, so it stays useful in a bare checkout.
 | Suite | Needs a server | Covers |
 |---|---|---|
 | `unit/test_list_filter.js` | no | `ListFilter` search/filter/sort/count/sticky, and the installed-plugins config **extracted verbatim** from `plugins_manager.js` so the test can't drift from it |
-| `unit/test_update_all.js` | no | `PluginInstallManager.updateAll` from `plugins/install_manager.js`: Check & Update All sends only plugin ids (never `starlark:` app entries), and re-sends a request that got no HTTP answer (web service restarting) instead of skipping that plugin. Also run by `test/web_interface/test_update_all_plugins.py` so CI covers it |
+| `unit/test_update_all.js` | no | `PluginInstallManager.updateAll` from `plugins/install_manager.js`: Check & Update All sends only plugin ids (never `starlark:` app entries), re-sends a request that got no HTTP answer (web service restarting) instead of skipping that plugin, never re-sends one that got any HTTP answer (the real `api_client.js` classifies a proxy 502 or a JSON error without `error_code` as `API_ERROR`), and counts a no-op update as already up to date in the summary. Also run by `test/web_interface/test_update_all_plugins.py` so CI covers it |
 | `unit/test_render_cards.js` | no | `renderInstalledCards` markup, both empty states, and HTML-escaping of hostile plugin metadata |
 | `unit/test_style_editor_element_keys.js` | no | `elementKeys()`/`styleRows()`/`positionRows()` from `widgets/style-editor.js`: every `customization.layout` entry gets exactly one row -- paired with its style element through core's `x-layout-key` (so `score` belongs to `score_text`, not a second row), or a position row of its own, leaves included -- since the widget claims the whole `layout` block from the generic fallback renderer |
 | `unit/test_style_editor_layout_leaf_columns.js` | no | `columnsFor()` from `widgets/style-editor.js`: a layout-only key whose own value is a leaf (no x/y sub-object, e.g. a `show_logo` toggle) gets a self-keyed column instead of a blank, uneditable row |

test/js/unit/test_update_all.js

@@ -146,6 +146,46 @@ const noSleep = { sleep: async () => {} };
     ok('...and is reported as a failure', results.find(x => x.pluginId === 'static-image').success === false);
   }
 
+  console.log('\nthe real api_client.js: only a missing HTTP answer is retried');
+  {
+    // The fake PluginAPI above decides error_code itself. This runs the shipped
+    // client so its classification is what gets tested: a proxy's 502 page or
+    // a JSON 500 without error_code used to come back as NETWORK_ERROR and be
+    // re-sent five more times.
+    const PluginAPI = require(path.join(V3, 'js/plugins/api_client.js'));
+    const run = async (makeFetch) => {
+      let requests = 0, sleeps = 0;
+      global.fetch = async () => { requests++; return makeFetch(requests); };
+      global.window = { PluginAPI, installedPlugins: [{ id: 'stock-news' }] };
+      const results = await Manager.updateAll(null, { sleep: async () => { sleeps++; }, retryDelaysMs: [1, 1, 1] });
+      return { requests, sleeps, result: results[0] };
+    };
+    const httpAnswer = (status, json) => ({ ok: status < 400, status, json });
+
+    let r = await run(() => httpAnswer(502, async () => { throw new SyntaxError('Unexpected token <'); }));
+    ok('a 502 with an HTML body is sent once', r.requests === 1 && r.sleeps === 0, r);
+    ok('...and is an API_ERROR carrying the status, not NETWORK_ERROR',
+       r.result.success === false && r.result.error.error_code === 'API_ERROR' && r.result.error.status === 502, r.result.error);
+
+    r = await run(() => httpAnswer(500, async () => ({ status: 'error', message: 'boom' })));
+    ok('a JSON 500 without error_code is sent once', r.requests === 1 && r.sleeps === 0, r);
+    ok('...and keeps the server message', r.result.error.message === 'boom', r.result.error);
+
+    r = await run(() => httpAnswer(500, async () => ({ status: 'error', error_code: 'PLUGIN_UPDATE_FAILED', message: 'x' })));
+    ok('a structured error is passed through unchanged',
+       r.requests === 1 && r.result.error.error_code === 'PLUGIN_UPDATE_FAILED', r.result.error);
+
+    r = await run((n) => {
+      if (n === 1) throw new TypeError('Failed to fetch');
+      return httpAnswer(200, async () => ({ status: 'success', message: 'ok', data: { update_status: 'updated' } }));
+    });
+    ok('a fetch() that rejects is NETWORK_ERROR and re-sent', r.requests === 2 && r.sleeps === 1 && r.result.success, r);
+
+    r = await run(() => httpAnswer(200, async () => { throw new SyntaxError('Unexpected end of JSON input'); }));
+    ok('an unreadable 200 is not retried either', r.requests === 1 && r.result.error.error_code === 'API_ERROR', r);
+    delete global.fetch;
+  }
+
   console.log('\nsummary: a no-op update is not counted as updated');
   {
     const answer = (update_status, message) => ({ success: true, result: { status: 'success', message, data: { update_status } } });