fix(share): preserve the shared query across the OAuth login redirect

A share link carries the SQL in the URL hash (#<base64>). When the recipient
wasn't signed in, the OAuth redirect to the IdP dropped the hash (redirect_uri is
path-only and fragments don't round-trip), and the in-memory tab was wiped by the
full-page navigation — so they landed on a blank /sql after signing in.

bootstrap now stashes the decoded query in sessionStorage (`oauth_shared_sql`),
which survives the same-tab redirect like oauth_state/verifier, and restores it
when the hash is gone, clearing it once consumed on a signed-in render.

Verified in-browser: not-signed-in load stashes the query + shows login; the
post-redirect load (no hash, signed in) restores it into the editor and clears
the stash. 353 tests pass; main.js at 100%.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QennTvGKAtJZrv9EpQagef

Author: 2 people

src/main.js

@@ -49,15 +49,24 @@ export async function bootstrap(app, env) {
     hist.replaceState(null, '', loc.origin + loc.pathname + (qs ? '?' + qs : '') + loc.hash);
   }
 
-  const sharedSql = decodeSqlFromHash(loc.hash);
+  // A shared query rides in the URL hash, which is lost through the OAuth
+  // redirect (and we strip it below). Stash it in sessionStorage so it survives
+  // the round-trip and restore it once we're back, signed in.
+  let sharedSql = decodeSqlFromHash(loc.hash);
+  if (sharedSql) ss.setItem('oauth_shared_sql', sharedSql);
+  else sharedSql = ss.getItem('oauth_shared_sql') || '';
   if (sharedSql) {
     app.state.tabs[0].sql = sharedSql;
     app.state.tabs[0].name = 'Shared query';
     hist.replaceState(null, '', loc.pathname + loc.search);
   }
 
-  if (app.token && !isTokenExpired(app.token, 0)) app.renderApp();
-  else app.showLogin(callbackError);
+  if (app.token && !isTokenExpired(app.token, 0)) {
+    ss.removeItem('oauth_shared_sql'); // consumed
+    app.renderApp();
+  } else {
+    app.showLogin(callbackError);
+  }
   return { callbackError, signedIn: app.isSignedIn() };
 }
 

tests/unit/main.test.js

@@ -120,14 +120,27 @@ describe('bootstrap', () => {
     expect(app.showLogin).toHaveBeenCalledWith('OAuth token exchange failed: plain failure');
   });
 
-  it('seeds the first tab from a share-link hash', async () => {
+  it('seeds the first tab from a share-link hash (and stashes it for login)', async () => {
     const app = fakeApp();
     const sql = 'SELECT 1';
     const hash = '#' + btoa(unescape(encodeURIComponent(sql)));
     const env = fakeEnv({ location: { href: 'https://ch/sql' + hash, origin: 'https://ch', pathname: '/sql', search: '', hash } });
     await bootstrap(app, env);
     expect(app.state.tabs[0].sql).toBe('SELECT 1');
     expect(app.state.tabs[0].name).toBe('Shared query');
+    expect(env.sessionStorage.getItem('oauth_shared_sql')).toBe('SELECT 1'); // survives a login redirect
+  });
+
+  it('restores a shared query from sessionStorage after the OAuth round-trip', async () => {
+    // The hash is gone after the IdP redirect; the stash carries it through.
+    const app = fakeApp({ token: valid, isSignedIn: () => true });
+    const env = fakeEnv({ location: { href: 'https://ch/sql', origin: 'https://ch', pathname: '/sql', search: '', hash: '' } });
+    env.sessionStorage.setItem('oauth_shared_sql', 'SELECT 42');
+    await bootstrap(app, env);
+    expect(app.state.tabs[0].sql).toBe('SELECT 42');
+    expect(app.state.tabs[0].name).toBe('Shared query');
+    expect(app.renderApp).toHaveBeenCalled();
+    expect(env.sessionStorage.getItem('oauth_shared_sql')).toBeNull(); // consumed on render
   });
 
   it('preserves extra query params while stripping oauth ones', async () => {