mirror: remove unnecessary shadowing

[wchargin]

Summary:
A common table expression shadows a (main or temporary) table name for
SELECT statements, but doing so is confusing and makes the code harder
to read.

Test Plan:
Existing unit tests suffice.

wchargin-branch: mirror-no-cte-shadow

[wchargin]

FWIW, I’m especially inclined to patch this because I wasn’t able to
find an official source on whether it’s well defined behavior. I asked
on the sqlite-users list, but haven’t heard back yet:
http://sqlite.1065341.n5.nabble.com/Shadowing-a-table-name-with-a-common-table-expression-td110832.html

[Beanow]

Needed to look a bit closer for what shadowing you meant.

sourcecred/src/graphql/mirror.js

Lines 1639 to 1646 in 5de027e

	db.prepare(
	dedent`\
	CREATE TEMPORARY TABLE transitive_dependencies (
	id TEXT NOT NULL PRIMARY KEY,
	typename TEXT NOT NULL
	)
	`
	).run();

Is created for that same extract method and used as the target table for a INSERT INTO ... FROM query. Meanwhile we're using the same name of transitive_dependencies as a CTE created from the WITH statement.

sourcecred/src/graphql/mirror.js

Lines 1663 to 1668 in 5de027e

	transitive_dependencies (id) AS (
	VALUES (:rootId) UNION
	SELECT direct_dependencies.child_id
	FROM transitive_dependencies JOIN direct_dependencies
	ON transitive_dependencies.id = direct_dependencies.parent_id
	)

[Beanow]

Agree it's better to avoid. Change LGTM

[wchargin]

Yes, that is correct.