fix(postgres): fix v15 migration failures on Postgres

[ili-ad]

Summary

Fix two PostgreSQL-specific failures encountered during bench --site iliad.local migrate on ERPNext v15.

Reproduction

• DB: PostgreSQL
• Run: bench --site iliad.local migrate

Fix 1: update_pick_list_fields fails on Postgres (UPDATE ... JOIN)

• Patch: erpnext.patches.v15_0.update_pick_list_fields
• Error: psycopg2.errors.SyntaxError: syntax error at or near "JOIN"
• Cause: MariaDB-style UPDATE <table> JOIN <table> is not supported on Postgres
• Change: use frappe.db.multisql:
  • MariaDB: keep existing UPDATE ... JOIN
  • Postgres: equivalent UPDATE ... SET ... FROM ... WHERE ...

Fix 2: allow_on_submit_dimensions_for_repostable_doctypes fails on Postgres (DISTINCT + ordering)

• Patch: erpnext.patches.v15_0.allow_on_submit_dimensions_for_repostable_doctypes
• Call chain: get_allowed_types_from_settings(child_doc=True) in
  erpnext/accounts/doctype/repost_accounting_ledger/repost_accounting_ledger.py
• Error: psycopg2.errors.InvalidColumnReference: for SELECT DISTINCT, ORDER BY expressions must appear in select list
• Cause: fields=["distinct(document_type)"] generates a SELECT DISTINCT ... query which conflicts with ordering rules on Postgres
• Change: replace distinct(document_type) with pluck="document_type" and de-duplicate results in Python while preserving order

Notes

• Scope is limited to migration code paths
• MariaDB behavior unchanged
• Target branch: version-15-hotfix

Summary by CodeRabbit

• Refactor
  • Improved retrieval and deduplication of document types eligible for reposting, preserving original order when expanding child document types.
  • Rewrote the delivery note pick-list synchronization to use a more direct, database-specific update approach for reliable propagation to line items.

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[coderabbitai]

Walkthrough

This change refactors two database-related operations. In repost_accounting_ledger, retrieval of allowed document types was changed from a DISTINCT(document_type) query to pluck-based fetching with application-level deduplication and preservation of order, and results are returned as single-element lists. In the v15 patch, delivery note pick_list propagation was rewritten from ORM-based updates to dialect-specific SQL: an UPDATE...JOIN for MariaDB and UPDATE...FROM for PostgreSQL.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: fixing PostgreSQL-specific failures in v15 migrations, which is the core focus of both file changes in the PR.

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🧹 Recent nitpick comments

erpnext/patches/v15_0/update_pick_list_fields.py (1)

2-2: Remove unused IfNull import.

The IfNull import is no longer used after refactoring to raw SQL with COALESCE. This is now dead code.

Suggested fix

 import frappe
-from frappe.query_builder.functions import IfNull

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📜 Recent review details

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 36228f6 and 626cab7.

📒 Files selected for processing (2)

• erpnext/accounts/doctype/repost_accounting_ledger/repost_accounting_ledger.py
• erpnext/patches/v15_0/update_pick_list_fields.py

🚧 Files skipped from review as they are similar to previous changes (1)

• erpnext/accounts/doctype/repost_accounting_ledger/repost_accounting_ledger.py

🧰 Additional context used

🧠 Learnings (2)

📓 Common learnings

Learnt from: vorasmit
Repo: frappe/erpnext PR: 51099
File: erpnext/patches/v16_0/migrate_tax_withholding_data.py:904-910
Timestamp: 2025-12-23T11:28:49.128Z
Learning: In the old Tax Withholding system (before the Tax Withholding Entry refactor), only one TCS account per Sales Invoice was supported. When reviewing migration code in erpnext/patches/v16_0/migrate_tax_withholding_data.py, the query selecting TCS accounts from GL Entries doesn't need explicit aggregation because historical data will only have one TCS account per invoice.

📚 Learning: 2025-12-16T05:33:58.723Z

Learnt from: Abdeali099
Repo: frappe/erpnext PR: 51078
File: erpnext/accounts/doctype/financial_report_template/financial_report_engine.py:486-491
Timestamp: 2025-12-16T05:33:58.723Z
Learning: In ERPNext/Frappe codebase, query.run(as_dict=True) returns frappe._dict objects that support both dict-style access (obj["key"]) and attribute-style access (obj.key). Therefore, attribute access on query results is valid and will not raise AttributeError. When reviewing Python code, prefer attribute access (obj.key) for readability where the key is known to exist, but ensure existence checks or fallback handling if there is any doubt about missing keys.

Applied to files:

• erpnext/patches/v15_0/update_pick_list_fields.py

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (6)

• GitHub Check: Python Unit Tests (3)
• GitHub Check: Python Unit Tests (1)
• GitHub Check: Python Unit Tests (4)
• GitHub Check: Python Unit Tests (2)
• GitHub Check: Patch Test
• GitHub Check: Summary

🔇 Additional comments (2)

erpnext/patches/v15_0/update_pick_list_fields.py (2)

10-28: LGTM!

The dialect-specific SQL is correctly structured for both databases:

• MariaDB uses the UPDATE ... JOIN syntax with backtick-quoted identifiers.
• PostgreSQL uses the UPDATE ... FROM syntax with double-quoted identifiers and the join condition in the WHERE clause.

The COALESCE filter ensures consistent behavior across both dialects.

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31-40: LGTM!

This single-table update using the query builder works correctly on both MariaDB and PostgreSQL. No changes needed here.

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🎉 This PR is included in version 15.95.0 🎉

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