fix: rewrite double-quoted DuckDB sources in WASM

[peter-gy]

Follow up of #9480.

Fixes DuckDB WASM SQL rewrites for read_csv("https://...") and other read_* functions. DuckDB accepts double-quoted file sources, but sqlglot represents them as quoted identifiers not string literals, so we skipped the WASM remote-source rewrite and raised.

This PR normalizes DuckDB string-like reader arguments before source validation.

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Jun 18, 2026 4:23pm

[Copilot]

Pull request overview

Fixes DuckDB WASM SQL remote-source rewrites when DuckDB readers (e.g. read_csv) are called with double-quoted URL arguments that sqlglot parses as quoted identifiers/columns rather than string literals. This ensures remote URL fetching/replacement-scan rewrites trigger correctly in Pyodide/WASM notebooks.

Changes:

• Normalize DuckDB “string-like” reader arguments by treating quoted identifiers/columns as string literal values for WASM source detection.
• Reuse the same normalization for option parsing so double-quoted string options don’t get rejected as dynamic.
• Add a regression test covering read_csv("https://...") rewrite behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
marimo/_runtime/_wasm/_duckdb/sources.py	Adds _string_literal_value() and uses it for reader source + option literal extraction, enabling double-quoted URL rewrites under sqlglot.
tests/_runtime/test_duckdb_wasm.py	Adds a unit test asserting wrapped_sql rewrites read_csv("https://...") and triggers the WASM fetch path.

[cubic-dev-ai]

No issues found across 2 files

Architecture diagram

sequenceDiagram
    participant Test as UserTest
    participant Wrapped as wrapped_sql()
    participant Parser as SQLParser (sqlglot)
    participant Rewriter as RewriteEngine
    participant StringLit as _string_literal_value (NEW)
    participant Fetch as fetch_url_bytes
    participant DuckDB as DuckDB Connection

    Test->>Wrapped: call wrapped_sql(read_csv("https://..."))
    Wrapped->>Parser: parse SQL to AST
    Parser-->>Wrapped: AST with read_csv Function
    Wrapped->>Rewriter: rewrite_remote_sources(AST)
    Rewriter->>Rewriter: find read_* functions
    Rewriter->>Rewriter: _read_function_source(args[0])

    Note over Rewriter: arg is exp.Column (double-quoted identifier)
    Rewriter->>StringLit: _string_literal_value(exp.Column)
    alt Identifier without table/db/catalog
        StringLit->>StringLit: check quoted identifier
        StringLit-->>Rewriter: "https://datasets.marimo.app/cars.csv"
    else old behavior (Identifier not Literal)
        Rewriter-->>Rewriter: would return None → raise error
    end

    Rewriter->>Rewriter: source is remote (https)
    Note over Rewriter: NEW: rewrite to use fetch_url_bytes
    Rewriter-->>Wrapped: rewritten SQL (fetches URL)
    Wrapped->>Fetch: fetch_url_bytes(url)
    Fetch-->>Wrapped: CSV bytes
    Wrapped->>DuckDB: execute(SELECT FROM read_csv_auto(bytes))
    DuckDB-->>Wrapped: relation
    Wrapped-->>Test: relation rows

    Note over Test,Fetch: Test asserts fetch_url_bytes called once

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