Render tabs as 4 spaces when pasting into clickhouse-client

[Algunenano]

Changelog category (leave one):

• Improvement

Changelog entry (a user-readable short description of the changes that goes into CHANGELOG.md):

Render tabs as 4 spaces when pasting into clickhouse-client. Closes #100405

Needs ClickHouse/replxx#37 merged first and then updating submodule

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

[clickhouse-gh]

Workflow [PR], commit [4654f7f]

Summary: ❌

job_name	test_name	status	info	comment
Stateless tests (amd_tsan, parallel, 2/2)		failure
	02889_file_log_save_errors	FAIL	cidb, issue	ISSUE CREATED
Stress test (amd_asan_ubsan)		failure
	Unknown error	FAIL	cidb, issue	ISSUE CREATED
Stress test (amd_msan)		failure
	Hung check failed, possible deadlock found	FAIL	cidb	IGNORED
Stress test (arm_msan)		failure
	Logical error: Can't adjust last granule because it has A rows, but try to subtract B rows (num_read_rows = C, total_rows_per_granule = D, rows_per_granule = [E], debug: max_rows=F, rows_from_read=G, rows_from_finalize_loop=H, rows_from_finalize_post=I, ranges_processed=J, skipped_marks=K, use_query_condition_cache=L, can_read_incomplete_granules=M) (STID: 5258-4a6f)	FAIL	cidb, issue	ISSUE CREATED
Stress test (arm_tsan)		error		IGNORED

---

AI Review

Summary

This PR updates contrib/replxx to render pasted tab characters as four spaces in interactive display while preserving literal tab bytes in the submitted query, and adds regression coverage in stateless tests (including an interactive expect scenario for bracketed paste mode). I did not find correctness, safety, concurrency, or performance issues in the introduced changes, and the PR metadata/changelog category appear aligned with the change.

ClickHouse Rules

Item	Status	Notes
Deletion logging	➖
Serialization versioning	➖
Core-area scrutiny	✅
No test removal	✅
Experimental gate	➖
No magic constants	✅
Backward compatibility	✅
SettingsChangesHistory.cpp	➖
PR metadata quality	✅
Safe rollout	✅
Compilation time	✅

Final Verdict

• Status: ✅ Approve

[azat]

I like the idea, but, there is one problem with it, if I will paste a query, the copy it back, I will have spaces not tabs

And the problem is only with copying what replxx renders I guess, but not with formatted query that is printed by ClickHouse AFAU

What do you think about this?

[azat]

Why this has been broken in #84412?
It should not use replxx at all AFAIU

[Algunenano]

Because it modified the query itself while pasting it, so ClickHouse got the modified query replacing any tab char with a space.

[azat]

It is still not clear, why non-interactive mode uses replxx.

[Algunenano]

Yes, in CI with clickhouse-client --queries this will not fail. I just took the failed query from the revert to add it as part of the PR just in case

[Algunenano]

And the problem is only with copying what replxx renders I guess, but not with formatted query that is printed by ClickHouse AFAU

I'll see if I can improve it, but the current status is much worse since replxx gives you a broken query:

~ $ clickhouse local
ClickHouse local version 26.4.1.1.

:) select
^I1,
^I2
from my_table

SELECT
    1,
    2
FROM my_table

Query id: ad9db4ad-4c7c-44fc-ab6b-7f081621b1cc


Elapsed: 0.049 sec. 

Received exception:
Code: 60. DB::Exception: Unknown table expression identifier 'my_table' in scope SELECT 1, 2 FROM my_table. (UNKNOWN_TABLE)

:) select
^I1,
^I2
from my_table

Syntax error: failed at position 8 (^) (line 2, col 1):

select
^I1,
^I2
from my_table

Expected one of: ALL, DISTINCT ON, DISTINCT, TOP, not empty list of expressions, list of expressions, list of elements, expression with optional alias, element of expression with optional alias, lambda expression, CAST operator, NOT, INTERVAL, CASE, DATE, TIMESTAMP, tuple, collection of literals, array, number, literal, NULL, NULL, Bool, TRUE, FALSE, string literal, asterisk, qualified asterisk, compound identifier, identifier, COLUMNS matcher, COLUMNS, qualified COLUMNS matcher, function name, substitution, MySQL-style global variable

[azat]

I'll see if I can improve it, but the current status is much worse since replxx gives you a broken query:

I see, then I guess we are good

[Algunenano]

I can force replxx to emit a tab character but it has 2 drawbacks:

• You need to update the cursor. I can make it 8 characters, which is the posix default, but if somebody changed it then it might cause issues.
• Even when you then copy the output from replxx and try again, at least in my terminal (konsole), the paste buffer already replaces tabs and you get spaces, so it's complicating things unnecessarily.

I'll merge this as is. I don't think it's worth the headache