ci(postgres): flag COALESCE/IfNull of a typed column with a mismatched-type literal (#56358)

ci(postgres): teach the guard about COALESCE(date, int) type mismatch

New class found by the whole-repo audit (the Asset Depreciations report fix in this PR): IfNull/Coalesce of a typed column with a different-typed literal -- e.g. IfNull(date_col, 0) -> COALESCE(date, integer), which PostgreSQL rejects (DatatypeMismatch). Added to the Greptile config and POSTGRES_COMPATIBILITY.md (not statically checkable without column types).

.github/POSTGRES_COMPATIBILITY.md

@@ -67,6 +67,12 @@ Flag a changed query that uses any of these:
   Use `VARCHAR` / `Cast_(x, "varchar")`.
 - **`.rlike()` / raw `RLIKE`** — frappe rewrites `REGEXP` → `~*` on PostgreSQL but does **not**
   translate `RLIKE` (no such PostgreSQL operator). Use `.regexp()` (or `.like()` for a simple prefix).
+- **`IfNull`/`Coalesce` of a typed column with a different-typed literal** — `IfNull(asset.disposal_date, 0)`
+  renders `COALESCE("disposal_date", 0)`, coalescing a **DATE** with an **integer**. PostgreSQL requires
+  `COALESCE` args to share a type (`DatatypeMismatch: COALESCE types date and integer cannot be matched`);
+  MariaDB's `IFNULL` is permissive. The common shape is `IfNull(date_col, 0) != 0 / == 0` as a presence test —
+  replace with `date_col.isnotnull()` / `date_col.isnull()` (identical, and valid on both). Otherwise coalesce
+  to a **same-type** default (`Coalesce(date_col, '1900-01-01')`, `Coalesce(text_col, '')`).
 
 ---
 

.greptile/config.json

@@ -7,7 +7,7 @@
             "frappe/frappe"
         ]
     },
-    "instructions": "ERPNext runs on both MariaDB and PostgreSQL from one codebase, but the PostgreSQL test job is label-gated and may not run on this PR, so review every new or changed database query (raw frappe.db.sql, frappe.qb, frappe.get_all/get_list/get_value, and report SQL) for cross-engine compatibility. PRIME RULE: MariaDB output must never change; PostgreSQL is bent to match MariaDB, never the reverse, so a change to the value, row count, or ordering MariaDB produced is a regression even if it looks more correct (the only accepted change is replacing an arbitrary/undefined result with a deterministic one, row count preserved, and it should be called out). Flag a changed query that (1) would ERROR on PostgreSQL: loose GROUP BY (selecting/ordering a column neither grouped nor aggregated -- including an aggregate like Sum()/Count() selected next to bare columns with NO .groupby() at all), MySQL-only functions (TIMESTAMP(date,time), TIMEDIFF, STR_TO_DATE, DATE_FORMAT, DATE_ADD/DATE_SUB, GROUP_CONCAT, PERIOD_DIFF, SQL IF()), .rlike()/RLIKE (frappe rewrites REGEXP->~* on PostgreSQL but does NOT translate RLIKE; use .regexp()), .like()/LIKE on a NON-text column such as idx/docstatus (bigint ILIKE has no operator; Cast_(col,'varchar') first), CAST AS CHAR / Cast(x,'char') (bare CHAR is character(1) on PostgreSQL and truncates multi-digit values; use 'varchar'), UPDATE..JOIN, HAVING on a SELECT alias, SELECT DISTINCT with an ORDER BY expr not in the select list, single-quoted column aliases, varchar bitwise OR, capital-cased identifiers used as fieldnames in get_value(dt,dn,'Status') or get_all(dt,fields=['Account']) (PostgreSQL matches the quoted identifier case-sensitively; use the stored lower-case name), or a Python bool written to a Check/int column via set_value/db_set/qb.update().set() instead of 1/0; or (2) would SILENTLY DIVERGE across engines: case-sensitive ==/.isin()/Strpos on USER-ENTERED free-text columns such as Data/Small Text/Long Text but NOT on Link/Select/name columns where exact-case matching is intended (PostgreSQL is case-sensitive, use Lower() both sides), lowercasing a value used as a document-name lookup, empty-string vs NULL in Concat/Concat_ws (MariaDB CONCAT(x,NULL) is NULL but PostgreSQL CONCAT drops the NULL, so a label like Concat('MFG-', nullable_date) leaks a bare 'MFG-' on PostgreSQL -- guard with Case/Coalesce/NullIf), NULL ordering (PostgreSQL sorts NULLs last) in ORDER BY..LIMIT 1, integer division (int/int truncates on PostgreSQL; multiply by 100.0 or make a literal a float, e.g. col/1440 -> col/1440.0), get_all(distinct=True, order_by=...) (frappe DROPS the ORDER BY for distinct queries on PostgreSQL, so sort in Python with key=str.casefold), an engine-specific function rewrite that does not match MariaDB on edge cases, or UnixTimestamp(date)/date-to-epoch math that is timezone-dependent (a strict epoch <= now bound is flaky on PostgreSQL). Also flag CATCH-AND-CONTINUE inserts: on PostgreSQL a failed insert aborts the WHOLE transaction (InFailedSqlTransaction), so code that swallows a duplicate/unique error and keeps going in the same transaction must wrap the fallible insert in frappe.db.savepoint(name) + rollback(save_point=name), unless it re-throws with no DB call before the throw or the insert uses ignore_if_duplicate=True or autoname='hash'. GROUP BY ROW-COUNT TRAP (most important): to make a loose GROUP BY PostgreSQL-valid, do NOT add a non-functionally-dependent column (the classic traps are the child/row primary key or an editable per-row field) to GROUP BY because that splits one row into N and changes the MariaDB row count; Max()/Min()-wrap it instead (row count preserved, value arbitrary to deterministic). Judge functional dependence by the SOURCE TABLE: a column from a master joined on the group key is FD and safe in GROUP BY, but a descriptive field on the transaction table (e.g. t1.supplier_name, t1.territory) is NOT FD and must be wrapped. Do NOT suggest changing a Max()-wrapped column to Sum() to make a number more correct, that changes MariaDB's value. DO NOT FLAG these false positives: .like()/['like'] on a TEXT column (already ILIKE on PostgreSQL -- but DO flag it on a non-text/integer column, see above), raw ifnull/backticks/LOCATE/REGEXP/.regexp() inside frappe.db.sql (auto-translated by the framework -- but RLIKE/.rlike() is NOT translated, see above), or an ORDER BY..LIMIT 1 tie where adding a tiebreaker would change MariaDB's current pick. Full catalog with examples and portable fixes is in .github/POSTGRES_COMPATIBILITY.md.",
+    "instructions": "ERPNext runs on both MariaDB and PostgreSQL from one codebase, but the PostgreSQL test job is label-gated and may not run on this PR, so review every new or changed database query (raw frappe.db.sql, frappe.qb, frappe.get_all/get_list/get_value, and report SQL) for cross-engine compatibility. PRIME RULE: MariaDB output must never change; PostgreSQL is bent to match MariaDB, never the reverse, so a change to the value, row count, or ordering MariaDB produced is a regression even if it looks more correct (the only accepted change is replacing an arbitrary/undefined result with a deterministic one, row count preserved, and it should be called out). Flag a changed query that (1) would ERROR on PostgreSQL: loose GROUP BY (selecting/ordering a column neither grouped nor aggregated -- including an aggregate like Sum()/Count() selected next to bare columns with NO .groupby() at all), MySQL-only functions (TIMESTAMP(date,time), TIMEDIFF, STR_TO_DATE, DATE_FORMAT, DATE_ADD/DATE_SUB, GROUP_CONCAT, PERIOD_DIFF, SQL IF()), .rlike()/RLIKE (frappe rewrites REGEXP->~* on PostgreSQL but does NOT translate RLIKE; use .regexp()), .like()/LIKE on a NON-text column such as idx/docstatus (bigint ILIKE has no operator; Cast_(col,'varchar') first), CAST AS CHAR / Cast(x,'char') (bare CHAR is character(1) on PostgreSQL and truncates multi-digit values; use 'varchar'), UPDATE..JOIN, HAVING on a SELECT alias, SELECT DISTINCT with an ORDER BY expr not in the select list, single-quoted column aliases, varchar bitwise OR, capital-cased identifiers used as fieldnames in get_value(dt,dn,'Status') or get_all(dt,fields=['Account']) (PostgreSQL matches the quoted identifier case-sensitively; use the stored lower-case name), a Python bool written to a Check/int column via set_value/db_set/qb.update().set() instead of 1/0, or IfNull/Coalesce of a typed column with a different-typed literal such as IfNull(date_col, 0) -> COALESCE(date, integer) (PostgreSQL: 'COALESCE types date and integer cannot be matched'; the common IfNull(date,0) != 0 / == 0 presence test should be date_col.isnotnull() / .isnull(), else coalesce to a same-type default); or (2) would SILENTLY DIVERGE across engines: case-sensitive ==/.isin()/Strpos on USER-ENTERED free-text columns such as Data/Small Text/Long Text but NOT on Link/Select/name columns where exact-case matching is intended (PostgreSQL is case-sensitive, use Lower() both sides), lowercasing a value used as a document-name lookup, empty-string vs NULL in Concat/Concat_ws (MariaDB CONCAT(x,NULL) is NULL but PostgreSQL CONCAT drops the NULL, so a label like Concat('MFG-', nullable_date) leaks a bare 'MFG-' on PostgreSQL -- guard with Case/Coalesce/NullIf), NULL ordering (PostgreSQL sorts NULLs last) in ORDER BY..LIMIT 1, integer division (int/int truncates on PostgreSQL; multiply by 100.0 or make a literal a float, e.g. col/1440 -> col/1440.0), get_all(distinct=True, order_by=...) (frappe DROPS the ORDER BY for distinct queries on PostgreSQL, so sort in Python with key=str.casefold), an engine-specific function rewrite that does not match MariaDB on edge cases, or UnixTimestamp(date)/date-to-epoch math that is timezone-dependent (a strict epoch <= now bound is flaky on PostgreSQL). Also flag CATCH-AND-CONTINUE inserts: on PostgreSQL a failed insert aborts the WHOLE transaction (InFailedSqlTransaction), so code that swallows a duplicate/unique error and keeps going in the same transaction must wrap the fallible insert in frappe.db.savepoint(name) + rollback(save_point=name), unless it re-throws with no DB call before the throw or the insert uses ignore_if_duplicate=True or autoname='hash'. GROUP BY ROW-COUNT TRAP (most important): to make a loose GROUP BY PostgreSQL-valid, do NOT add a non-functionally-dependent column (the classic traps are the child/row primary key or an editable per-row field) to GROUP BY because that splits one row into N and changes the MariaDB row count; Max()/Min()-wrap it instead (row count preserved, value arbitrary to deterministic). Judge functional dependence by the SOURCE TABLE: a column from a master joined on the group key is FD and safe in GROUP BY, but a descriptive field on the transaction table (e.g. t1.supplier_name, t1.territory) is NOT FD and must be wrapped. Do NOT suggest changing a Max()-wrapped column to Sum() to make a number more correct, that changes MariaDB's value. DO NOT FLAG these false positives: .like()/['like'] on a TEXT column (already ILIKE on PostgreSQL -- but DO flag it on a non-text/integer column, see above), raw ifnull/backticks/LOCATE/REGEXP/.regexp() inside frappe.db.sql (auto-translated by the framework -- but RLIKE/.rlike() is NOT translated, see above), or an ORDER BY..LIMIT 1 tie where adding a tiebreaker would change MariaDB's current pick. Full catalog with examples and portable fixes is in .github/POSTGRES_COMPATIBILITY.md.",
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