Summary

This PR adds a hidden config option, logger.hideWelcomeMessage, to suppress startup welcome/URL terminal output, and wires it into bootstrap._print_url(). It also includes a targeted unit test for the new suppression behavior and a small wording cleanup in Snowflake connection log messages.

Code Quality

The changes are small, focused, and follow existing patterns in the config and bootstrap modules.
No code quality issues were identified in the modified files:

• lib/streamlit/config.py
• lib/streamlit/web/bootstrap.py
• lib/streamlit/connections/snowflake_connection.py
• lib/tests/streamlit/config_test.py
• lib/tests/streamlit/web/bootstrap_test.py

Test Coverage

Coverage for the new behavior is good for a scoped config addition:

• lib/tests/streamlit/config_test.py validates the new config key is registered.
• lib/tests/streamlit/web/bootstrap_test.py adds a regression test that verifies _print_url() emits no output when logger.hideWelcomeMessage=True.

No e2e coverage was added, which is acceptable for this internal, hidden config path; residual risk is low and mostly limited to startup logging behavior.

Backwards Compatibility

No breaking changes detected.

• The new option is hidden and defaults to False, so existing behavior is unchanged unless explicitly enabled.
• Existing startup output remains intact for all current users by default.
• The Snowflake logging text changes are message-only and do not affect behavior or API contracts.

Security & Risk

No security concerns identified.

Regression risk appears low:

• The functional change is a single early return in _print_url() gated by an explicit config flag.
• The option does not alter network binding, auth, or request handling behavior.

Accessibility

No frontend/UI changes in this PR; accessibility impact is not applicable.

Recommendations

1. Optional: add one additional unit assertion for the non-hello path (_print_url(False)) with logger.hideWelcomeMessage=True to make intent explicit across both title branches.

Verdict

APPROVED: The implementation is focused, backward compatible, and adequately tested for the new hidden config behavior.

This is an automated AI review by gpt-5.3-codex-high. Please verify the feedback and use your judgment.

Summary

This PR adds a new hidden config option logger.hideWelcomeMessage that suppresses the welcome/URL message printed when starting a Streamlit server. When set to True, the "Welcome to Streamlit" / "You can now view your Streamlit app" output (including Local URL, Network URL, and External URL) is suppressed. This is intended for hosted environments (e.g. Streamlit in Snowflake) where the default messages showing localhost URLs are misleading.

Additionally, a minor grammar fix changes "Connect to Snowflake..." to "Connecting to Snowflake..." in two log messages in snowflake_connection.py.

Code Quality

The implementation is clean and minimal:

• lib/streamlit/config.py (lines 550-564): The new config option is well-placed in the logger section, correctly marked as visibility="hidden", uses bool type with a False default, and has a clear description. The placement follows alphabetical order within the section.

• lib/streamlit/web/bootstrap.py (lines 236-237): The early-return guard at the top of _print_url is the simplest correct approach. It prevents all output — title message, URLs, and the hello footer — with a single check.

• lib/streamlit/connections/snowflake_connection.py (lines 643, 652): The grammar fix ("Connect" -> "Connecting") is trivial and correct. Using the present participle is more natural for a log message emitted while an action is in progress.

No issues with code structure or patterns.

Test Coverage

• lib/tests/streamlit/config_test.py (line 769): The new option is correctly added to the exhaustive config key list in alphabetical order.

• lib/tests/streamlit/web/bootstrap_test.py (lines 66-72): The new test test_print_url_hidden_when_config_set verifies that stdout is empty when the config is enabled. The test uses patch_config_options which is idiomatic for the project. The test has a descriptive docstring, consistent with project guidelines.

Minor observations:

• The test only exercises is_running_hello=True, but since the early return occurs before that parameter is read, testing both values would be redundant.
• The test method lacks a -> None return type annotation (per lib/tests/AGENTS.md: "New tests should be fully annotated with types"), but all existing methods in this unittest class also omit annotations, so this is consistent with the file's conventions.
• There is no negative test verifying that the welcome message still prints when logger.hideWelcomeMessage is False (the default). However, the existing test_print_hello_message and test_print_urls_configured tests already exercise _print_url without this config set (defaulting to False) and assert output is produced, which implicitly covers this.

Overall, test coverage is adequate for the scope of this change.

Backwards Compatibility

No breaking changes:

• The config option defaults to False, so existing behavior is unchanged.
• The option has visibility="hidden", so it does not appear in user-facing config documentation or streamlit config show.
• No public API surface is modified.
• The Snowflake log message wording change is internal and has no user-facing impact.

Security & Risk

No security concerns identified:

• The change only affects CLI output suppression; no authentication, network, or data-handling logic is modified.
• The config option is hidden and boolean-only, with no injection surface.
• Risk of regression is minimal — the guard is a simple early return with no side effects.

Accessibility

Not applicable — this PR modifies only backend Python code (CLI output and config). No frontend or UI changes are involved.

Recommendations

No blocking issues. Minor suggestions for consideration:

1. Type annotation on test method: Consider adding -> None to test_print_url_hidden_when_config_set for consistency with the lib/tests/AGENTS.md guideline about fully annotated new tests. This is a nit given the existing file conventions.

Verdict

APPROVED: Clean, well-scoped addition of a hidden config option to suppress the welcome message in hosted environments. Implementation is correct, tests are adequate, and there are no backwards compatibility or security concerns.

This is an automated AI review by opus-4.6-thinking.