[Harshg999]

What changes are proposed in this pull request?

Fixes a set of problems in the native Trino connector (interface=trino) so that basic Trino support works reliably, and adds an opt-in switch for API-defined custom connectors.

Trino connector (notebook/connectors/trino.py)

• Use basic authentication only over HTTPS (the Trino client refuses it over HTTP). Over http:// the credentials are ignored with a warning instead of failing. Empty auth_username / auth_password options fall back to the global defaults.
• New options: ssl_verify (true, false or a CA bundle path) and trino_user (user sent to Trino, defaults to the Hue user).
• The default port now follows the URL scheme (443 for https, 8080 otherwise).
• Metadata queries (SHOW CATALOGS, tables, columns, schemas, sample data, explain) read all result pages. They previously read only the first page, so large results were cut.
• SHOW SCHEMAS FROM quotes the catalog name, and USE is skipped when no database is given.
• has_more is correct when the last fetched page still has rows to return.
• Add cancel(), which deletes the Trino next URI.
• The query error handler no longer uses the Python 2 only ex.message.
• create_session no longer shares a mutable properties default.

[notebook] enable_custom_connectors (default false)

• A snippet of type custom lets an API client choose the interface and options, so the host the Hue server connects to. It is now disabled by default and can be enabled by an admin.
• Connectors defined in hue.ini are not affected.
• The legacy RDBMS/JDBC importer builds its own custom snippets on the server and bypasses the flag.
• Behavior change: API clients that rely on custom snippets need enable_custom_connectors=true.

Docs and config

• Updated the Trino examples in hue.ini and pseudo-distributed.ini.tmpl and the connectors documentation. Added the new flag.

How was this patch tested?

• Unit tests: 190 passed in notebook and indexer, including new tests for auth, ssl_verify, trino_user, paging, cancel, the gate and the interpreter config. Added a jest test for sqlUtils.backTickIfNeeded with the trino dialect (6 tests). ruff is clean on the changed files.
• End to end against trinodb/trino:476 through the notebook API:
  • catalog, schema and table browsing, sample data and explain
  • error handling
  • paging (15,000 and 60,175 rows read exactly)
  • cancel (the query ends as USER_CANCELED on the server)
  • HTTPS with basic auth and a password file: ssl_verify as false, as a CA bundle path and as the default (refused for a self-signed certificate), auth_password_script, and a wrong password (clean 401)
  • trino_user
  • credentials over http://: ignored with a warning

Not covered: Kerberos, JWT and OAuth (not supported by this connector) and the browser UI itself.

[github-actions]

✅ Test files were modified. Ensure that the tests cover all relevant changes. ✅

[github-actions]

UI Code Coverage Report

Lines	Statements	Branches	Functions
	40.16% (31638/78763)	32.07% (14993/46738)	26.41% (2415/9142)

[github-actions]

Backend Code Coverage Report •

File	Stmts	Miss	Branch	BrPart	Cover	Missing
desktop/libs/indexer/src/indexer/indexers
rdbms.py	148	119	56	54	15%	37–39, 41, 43–48, 50–55, 57, 64->87, 66->75, 75–76, 85, 87–88, 90–93, 105–108, 110, 114–117, 119, 121, 125–139, 141–142, 144, 146–151, 153–158, 164–169, 175–180, 182–183, 189–190, 199–201, 203, 209–210, 212–217, 223, 228–229, 239–240, 243–244, 247–251, 257, 268–270, 273, 278, 293–294, 296, 300–301, 305
desktop/libs/notebook/src/notebook/connectors
base.py	433	190	159	90	53%	56, 61, 76, 159, 161, 173, 175, 178, 180, 191, 193, 196, 198, 208, 210, 213, 215, 227, 229, 233, 235–242, 244, 258, 260, 263, 279, 281–282, 290, 292–294, 296, 306->307, 307, 315->340, 317->322, 340, 348, 350, 359->360, 360, 367->368, 368, 375->376, 376, 393->394, 394, 404->405, 405–408, 409->410, 410–411, 412->413, 413, 428->429, 429, 431->432, 432, 439->440, 440–441, 442->443, 443–444, 445->449, 469->470, 470, 471->472, 472–473, 474->475, 475–476, 477->478, 478–479, 480->481, 481–482, 483->484, 484–501, 503–504, 505->506, 506–507, 508->509, 509–510, 511->512, 512–513, 514->515, 515–516, 517->518, 518–519, 520->521, 521–522, 523->524, 524–525, 526->527, 527–528, 529->530, 530–531, 532->535, 535–539, 541, 545–547, 549, 563, 570, 573, 579, 596, 599, 602, 605, 608, 611, 618, 621, 624, 627–628, 630–631, 633, 636–637, 639, 641, 644–645, 647, 649, 652–655, 668–669, 671, 679–681, 684, 687–690, 693, 695->exit, 699->700, 700–703, 708, 713->714, 714, 728->741, 735->736, 736, 741->744, 744, 749->752, 752–755, 757–764, 766–767, 769–776, 779->exit
trino.py	301	78	110	41	71%	46->53, 53–55, 130->139, 175->176, 176, 186–187, 189–192, 194, 249->250, 250, 254->255, 255, 256->257, 257, 274->277, 280–281, 287->288, 288–289, 325->336, 350->351, 351, 375–377, 379, 388, 407–408, 410, 426–427, 429, 447->454, 461, 463–464, 466–467, 473–474, 477–479, 481–482, 484–485, 487–488, 490–493, 495, 498–499, 501–504, 506–515, 517–518, 520–528
TOTAL	56859	28774	21937	12923	47%

[agl29]

LGTM!