fix(core): Truncate db aliases if necessary

[jnugh]

Fixes #2899

Description

Postgres truncates long identifiers making them equal if they share the same prefix. For instance if two tables are being joined with a long alias (the names need to be a lot longer in reality) product_variant_relation_0_relation_1 and product_variant_relation_0_relation_2 postgres will truncate both aliases to product_variant_rel and fail because it's not allowed to have two join statements with the same target alias.

Breaking changes

None

Checklist

📌 Always:

• I have set a clear title
• My PR is small and contains a single feature
• I have checked my own PR

👍 Most of the time:

• I have added or updated test cases
• I have updated the README if needed

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated (UTC)
docs	✅ Ready (Inspect)	Visit Preview	Aug 5, 2024 8:42am

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[jnugh]

I have read the CLA Document and I hereby sign the CLA

[michaelbromley]

Hi,

Thanks for this contribution!

Since this is quite a low-level modification, and heavily subject to the TypeORM internals, I'm wondering if there is some way we can add a test for this that:

1. Fails before your modification
2. Passes after it
3. Will therefore detect regressions in future changes to TypeORM

Do you think this is something you can look into?

[jnugh]

Sorry for the long delay. I implemented a test case, inside the entity hydrator test suite. Without the fix the test will fail with:

Serialized Error: { response: { errors: [ { message: 'table name "TreeEntity_childrenPropertyWithAVeryLongNameThatExceedsPostgres" specified more than once', locations: [ { line: 2, column: 3 } ], path: [ 'hydrateChannelWithVeryLongPropertyName' ] } ], data: { hydrateChannelWithVeryLongPropertyName: null }, status: 200 }, request: { query: 'query GetHydratedChannelNested($id: ID!) {\n  hydrateChannelWithVeryLongPropertyName(id: $id)\n}', variables: { id: 'T_1' } } }

[michaelbromley]

Excellent work, thanks so much!