fix: fix crash in scalar caused by window function without from

[dapan1121]

…s in query without FROM

Defect: #6935331548

Root cause: Window pseudo-column functions (_wend, _wstart, _wduration, _irowts, _isfilled) were not rejected at parse time in no-FROM (dual) queries. They reached the scalar execution layer where winEndTsFunction tried to read row data from empty/uninitialized input via colDataGetData(pInput->columnData, 4), causing a SIGSEGV at source/libs/scalar/src/sclfunc.c:4748.

Fix in parser (parTranslater.c):

• Add validateDualQueryFunc called from translateFunction that rejects at parse time all functions unsupported without a table: UDFs, window pseudo-column funcs, and agg funcs that have no scalar exec path
• Client pseudo-column funcs (_qstart, _qend, _qduration) are allowed as they are rewritten to constants by rewriteClientPseudoColumnFunc
• Add early return in rewriteCountStar and rewriteCountNotNullValue when pCxt->dual is set; this also fixes count(1)/count(*) without FROM incorrectly returning TABLE_NOT_EXIST (found during investigation)

Fix in scalar (scalar.c):

• Correct the boolean condition in sclRewriteFunction from (!scalar && !dual) || UDF to !dual && (!scalar || UDF) so that in dual mode all functions are routed to scalar execution (no premature DEAL_RES_CONTINUE skip) while in normal mode non-scalar functions and UDFs are still skipped for executor handling

Test: add test/cases/11-Functions/09-NoFrom/test_fun_no_from_all.py covering 120+ positive cases and 11 negative cases; register in cases.task

Description

Issue(s)

• Close/close/Fix/fix/Resolve/resolve: Issue Link

Checklist

Please check the items in the checklist if applicable.

• Is the user manual updated?
• Are the test cases passed and automated?
• Is there no significant decrease in test coverage?

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[Copilot]

Pull request overview

This PR fixes a crash triggered by using window pseudo-column functions (e.g., _wend, _wstart) in SELECT ... queries without a FROM clause by rejecting unsupported functions during parsing and adjusting scalar constant-folding behavior in dual-query mode.

Changes:

• Add parser-side validation for dual (no-FROM) queries to reject UDFs, window pseudo-column functions, and non-scalar functions without a scalar execution path.
• Fix scalar rewrite routing so dual-mode functions are evaluated in the scalar layer rather than being prematurely skipped.
• Add a comprehensive no-FROM function test suite and register it in CI.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
source/libs/parser/src/parTranslater.c	Adds dual-query function validation and adjusts count(*) / count(1) rewrites for no-FROM queries.
source/libs/scalar/src/scalar.c	Fixes conditional logic so dual-mode function rewriting/execution is routed correctly.
test/cases/11-Functions/09-NoFrom/test_fun_no_from_all.py	New test covering many supported/unsupported function calls in no-FROM queries.
test/ci/cases.task	Registers the new no-FROM test in CI task list.

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