fix: correct LANGUAGE for overloaded functions with mixed languages (#368)

[tianzhou]

Summary

• Fixed cross-join in the information_schema.routines ↔ pg_proc JOIN that caused overloaded functions with different languages to get the wrong LANGUAGE assigned
• Added OID matching via specific_name to all 4 affected queries (GetFunctions, GetProcedures, GetFunctionsForSchema, GetProceduresForSchema)
• Merged mixed-language overload test into existing issue_191_function_procedure_overload test case

Fixes #368

Test plan

• New test scenario added to TestDumpCommand_Issue191FunctionProcedureOverload with sql vs plpgsql overloads
• Existing function/procedure dump tests pass (issues Regression: losing default arguments #125, Force qualified names in dump #252, Truncated functions in grants #275, Respect quoted identifiers in plpgsql functions when dumping schema #320)
• Diff tests pass (create_function/, create_procedure/)

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

This PR fixes a cross-join bug in the information_schema.routines ↔ pg_proc JOIN that caused overloaded functions with different languages to be assigned the wrong LANGUAGE in the dump output. The fix adds AND p.oid = (regexp_match(r.specific_name, '_(\d+)$'))[1]::oid to the JOIN condition in all 4 affected queries, using the OID embedded in specific_name to uniquely identify each function/procedure row.

Key changes:

• ir/queries/queries.sql and ir/queries/queries.sql.go: All 4 queries (GetFunctions, GetProcedures, GetFunctionsForSchema, GetProceduresForSchema) now include the OID-based join condition.
• testdata/dump/issue_191_function_procedure_overload/: Test scenario extended with provide_tx(VARIADIC text[]) (sql) and provide_tx(uuid) (plpgsql) mixed-language overloads to exercise the fix.
• cmd/dump/dump_integration_test.go: Adds TestDumpCommand_Issue191FunctionProcedureOverload as the first proper test function wired to the existing issue_191 test data directory.

The approach is sound: information_schema.routines.specific_name in PostgreSQL is always formatted as <routine_name>_<oid>, making the regex _(\d+)$ a reliable, well-established way to extract the OID for an unambiguous JOIN. The proname and pronamespace conditions are technically redundant once the OID is matched, but they serve as harmless defensive guards. The version header change in the snapshot file (PostgreSQL 17.5 → 18.0) is cosmetic — normalizeSchemaOutput strips those lines before comparison.

Confidence Score: 5/5

• Safe to merge — targeted, correct fix with comprehensive test coverage and no side-effects on non-overloaded functions.
• The OID-based join via specific_name is the canonical PostgreSQL approach to disambiguating overloaded routines in information_schema.routines. All 4 affected queries are updated consistently in both the SQL source and the generated Go file, and the new mixed-language test scenario directly reproduces the reported bug. No regressions are introduced since the OID condition only tightens the existing name + namespace match.
• No files require special attention.

Important Files Changed

Filename	Overview
ir/queries/queries.sql	Core SQL fix: adds AND p.oid = (regexp_match(r.specific_name, '_(\d+)$'))[1]::oid to the LEFT JOIN in all 4 queries (GetFunctions, GetProcedures, GetFunctionsForSchema, GetProceduresForSchema), correctly resolving the cross-join that assigned wrong LANGUAGEs to overloaded functions.
ir/queries/queries.sql.go	Auto-generated Go file kept in sync with queries.sql; all 4 affected queries consistently updated with the OID-matching join condition.
cmd/dump/dump_integration_test.go	Adds TestDumpCommand_Issue191FunctionProcedureOverload as the first proper test function for the issue_191 test data directory; the test infrastructure (runExactMatchTest / normalizeSchemaOutput) strips version headers so the snapshot is version-agnostic.
testdata/dump/issue_191_function_procedure_overload/pgschema.sql	Expected pgschema dump snapshot updated with both provide_tx overloads using their correct LANGUAGE (sql vs plpgsql); version header change (17.5→18.0) is cosmetic and stripped at comparison time.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[information_schema.routines row\ne.g. provide_tx with specific_name='provide_tx_12345'] --> B{JOIN pg_proc}

    subgraph OLD["Before fix (cross-join)"]
        B1["ON proname = routine_name\nAND pronamespace = schema_oid"]
        B1 --> C1["Matches ALL overloads\nwith same name"]
        C1 --> D1["provide_tx_12345 gets LANGUAGE plpgsql\n(from wrong overload)"]
    end

    subgraph NEW["After fix (OID-pinned)"]
        B2["ON proname = routine_name\nAND pronamespace = schema_oid\nAND oid = extract_oid(specific_name)"]
        B2 --> C2["Matches EXACTLY ONE pg_proc row\nvia OID from specific_name"]
        C2 --> D2["provide_tx_12345 gets LANGUAGE sql ✓\nprovide_tx_67890 gets LANGUAGE plpgsql ✓"]
    end

    B --> B1
    B --> B2

    E["specific_name format\n'provide_tx_12345'\n→ regexp_match('_(\d+)$')\n→ OID 12345\n→ cast to ::oid"] --> B2

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[Copilot]

Pull request overview

This PR fixes routine introspection so overloaded functions/procedures are joined to the correct pg_proc row, preventing mixed-language overloads from being dumped with an incorrect LANGUAGE (fixing #368) and expanding coverage in the existing overload dump fixture (#191).

Changes:

• Updates the information_schema.routines ↔ pg_proc join to additionally match the routine OID derived from r.specific_name (applied to 4 queries).
• Extends the issue_191_function_procedure_overload dump fixture to include a same-name overload pair with different languages (sql vs plpgsql).
• Adds an integration test entry to run the issue_191_function_procedure_overload exact-match dump fixture.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
ir/queries/queries.sql	Fixes routine ↔ pg_proc joining by uniquely matching on OID extracted from specific_name, preventing overload cross-joins.
ir/queries/queries.sql.go	Regenerates the sqlc output to reflect the updated SQL joins.
testdata/dump/issue_191_function_procedure_overload/raw.sql	Adds mixed-language overload DDL to reproduce/cover #368 in the existing fixture.
testdata/dump/issue_191_function_procedure_overload/pgschema.sql	Updates expected pgschema dump output to include both overloads with correct LANGUAGE.
testdata/dump/issue_191_function_procedure_overload/pgdump.sql	Updates pg_dump input fixture to include the new overloads.
testdata/dump/issue_191_function_procedure_overload/manifest.json	Updates fixture metadata to reflect covering both #191 and #368.
cmd/dump/dump_integration_test.go	Adds an integration test function to execute the updated overload fixture.

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