fix: recreate non-view dependents around a function DROP + CREATE (#601) by christophostertag · Pull Request #622 · pgplex/pgschema

christophostertag · 2026-09-24T01:48:31Z

Summary

Follow-up to #619. A function change that CREATE OR REPLACE cannot apply (return type, parameter names, OUT parameters) is planned as DROP FUNCTION + CREATE FUNCTION (#326). #619 moved calling views through that cycle; the other objects PostgreSQL records a dependency for still made apply fail with cannot drop function ... because other objects depend on it (SQLSTATE 2BP01), e.g. a column DEFAULT lim() when lim() changes from integer to bigint — the limitation #619 left open.

Changes

Held dependents (internal/diff/function_dependents.go): column defaults, CHECK and EXCLUDE constraints, expression and partial indexes, policies, trigger WHEN conditions, and domain defaults/CHECK constraints whose desired definition calls a recreated function are taken out of the regular table/domain diff. Their current version is dropped right before the function and the desired version is created right after it, in the same transaction. Index changes of kept materialized views (built CONCURRENTLY, i.e. in transactions of their own) wait until the restores are done, and the regular diff leaves held objects alone (a held column default keeps its current value until the drop right before the function), so drops, recreation and restores share one transaction — with the one exception of GENERATED ALWAYS AS expression changes are ignored by plan #591's early drops noted below; TestHeldDependentsShareOneTransaction checks, for every diff test case, that the held steps form one transaction and that nothing else changes a held object outside it. Unchanged, modified and new dependents are handled alike; objects whose old definition calls the function but whose new one does not stay with the regular diff. An EXCLUDE constraint, policy or trigger naming a column the diff re-creates (GENERATED ALWAYS AS expression changes are ignored by plan #591) is still dropped before that column.
New tables and domains are created without the held objects, which follow the function.
Online semantics: a rebuilt index is created without CONCURRENTLY (the table is never without it, e.g. a unique expression index), a CHECK on an existing table is re-added NOT VALID and validated in its own transaction once everything is back, and an index that did not exist before keeps the usual concurrent rewrite.
Partitioned tables: held defaults use ALTER TABLE ONLY, so partitions keep defaults of their own; partitions leave the CHECK constraints and indexes they inherit to their parent.
Materialized views whose index (not only the query) calls a recreated function go through the fix: recreate dependent views around a function DROP + CREATE (#601) #619 recreate path.
Plan-time refusal (ValidateFunctionRecreations, called from GeneratePlan): a generated column that calls a recreated function (keeping it would require dropping and re-adding the column; on PG14 the DROP FUNCTION even drops it silently), or a column added to an existing table — or re-created by GENERATED ALWAYS AS expression changes are ignored by plan #591, e.g. VIRTUAL to plain — whose default (its own, or its domain type's) calls one: its existing rows would be filled before the function exists again, by the old function or with NULL. A column whose type or collation changes while its new default calls a recreated function is refused as well (change the type or collation in a separate step). The error names the column and the function.

No CASCADE is used; drops are RESTRICT/IF EXISTS.

Lock note: the drops take ACCESS EXCLUSIVE on the affected tables until the transaction commits, and a rebuilt index is built under that lock. VALIDATE CONSTRAINT runs afterwards with SHARE UPDATE EXCLUSIVE.

Behavior change: CHECK constraints declared NOT VALID

Needed so a restored NOT VALID CHECK keeps its state, and a bug on its own: a desired ALTER TABLE ... ADD CONSTRAINT ... CHECK (...) NOT VALID on an existing table was rewritten to ADD ... NOT VALID + VALIDATE CONSTRAINT. With rows violating it, apply failed with SQLSTATE 23514; without, the constraint ended up validated and every later plan re-emitted DROP CONSTRAINT / ADD ... NOT VALID / VALIDATE. It is now added NOT VALID without VALIDATE (new case online/add_check_not_valid). Foreign keys declared NOT VALID have the same problem and are left unchanged here.

Known limitations

Matching is by function name, as in fix: recreate dependent views around a function DROP + CREATE (#601) #619: an overload of a recreated function causes a redundant drop and rebuild of its callers (with the lock cost above), and a generated column calling another overload is refused.
Generated columns calling a recreated function are refused, not handled; re-creating them GENERATED ALWAYS AS expression changes are ignored by plan #591-style around the function would be a possible follow-up.
Not handled (still 2BP01): SQL-standard-body functions (RETURN/BEGIN ATOMIC) calling the function, expression partition keys (not modeled by the IR), aggregates using it as a support function, objects outside the managed schema.
Policy and constraint comments are not part of the IR (pgschema dump omits them and changing them plans as no change), so a re-created policy/constraint loses a comment set outside pgschema, as with any policy/constraint pgschema re-creates today.
A partition's CHECK constraint with the same name as its parent's (merged by PostgreSQL) is treated as inherited.
An EXCLUDE constraint, policy or trigger naming a column the diff re-creates (GENERATED ALWAYS AS expression changes are ignored by plan #591) keeps GENERATED ALWAYS AS expression changes are ignored by plan #591's early drop before the DROP COLUMN, so it is outside the single-transaction span.

Refs #601, follows #619.

Test plan

New cases in testdata/diff/dependency/: issue_601_function_recreate_unchanged_dependents, …_changed_dependents (modified, added, new table), …_domain_exclude_not_valid, …_partitioned_table, …_trigger_with_online_steps, …_with_matview_index_change and …_with_table_online_steps (other objects' online steps stay outside the function's transaction; default-only and SET NOT NULL changes keep their default until then), …_with_enum_value (enum ADD VALUE commits before it); plus online/add_check_not_valid, TestValidateFunctionRecreations* and TestHeldDependentsShareOneTransaction.

PGSCHEMA_TEST_FILTER="dependency/issue_601" go test -v ./internal/diff -run TestDiffFromFiles
PGSCHEMA_TEST_FILTER="dependency/issue_601" go test -v ./cmd -run TestPlanAndApply
PGSCHEMA_TEST_FILTER="online/add_check_not_valid" go test -v ./cmd -run TestPlanAndApply
go test -v ./internal/diff -run TestValidateFunctionRecreations
go test -v ./internal/plan -run TestHeldDependentsShareOneTransaction

Confirmed red before the fix (2BP01, and 23514 for the NOT VALID case). Full go test ./... passes locally (PG18). Also verified with the CLI (external plan database, saved-plan apply, repeat plan empty) on PostgreSQL 14–18, including runtime behavior: defaults use the new function and partition defaults survive, CHECK/EXCLUDE/unique index/policy are enforced (policy for a non-owner role), triggers fire on the new condition, unrelated objects keep their OIDs.

🤖 Generated with Claude Code

…plex#601) A function change that CREATE OR REPLACE cannot apply is planned as DROP FUNCTION + CREATE FUNCTION (pgplex#326). pgplex#619 moved the calling views through that cycle; the other objects PostgreSQL records a dependency for still made the DROP fail with SQLSTATE 2BP01. Column defaults, CHECK and EXCLUDE constraints, expression and partial indexes, policies, trigger WHEN conditions and domain defaults and CHECK constraints whose desired definition calls a recreated function are now held: the regular table and domain diff leaves them alone, their current version is dropped right before the function and the desired version is created right after it. Drops, recreation and restores share one transaction: index changes of kept materialized views, which the plan builds CONCURRENTLY, wait until the restores are done, and a test checks every diff case for a transaction boundary inside that span or a change to a held object outside it. A rebuilt index is created without CONCURRENTLY so the table is never without it, and a CHECK constraint on an existing table is added NOT VALID and validated in a transaction of its own afterwards. New tables and domains are created without the held objects, which follow the function. Objects naming a column the diff re-creates (pgplex#591) keep their early drop. The regular column diff leaves a held default as it is. Defaults on partitioned tables are changed with ALTER TABLE ONLY so partitions keep defaults of their own, and partitions leave the CHECK constraints and indexes they inherit to their parent. A materialized view whose index calls the function is recreated like one whose query does. Rejected at plan time, with the column and function named: a generated column calling a recreated function, a column added or re-created (pgplex#591) whose default - its own or its domain type's - calls one, since its existing rows would be filled before the function exists again, and a column whose type changes while its new default calls one. A CHECK constraint the desired state declares NOT VALID is now added NOT VALID without VALIDATE; the online rewrite validated it anyway, which failed with SQLSTATE 23514 when existing rows violate it and otherwise re-planned the constraint on every run. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

greptile-apps · 2026-09-24T01:51:47Z

Confidence Score: 5/5

The PR appears safe to merge with no accepted correctness or security findings.

Summary

This PR extends function recreation planning so PostgreSQL objects that depend on a function are removed and restored around its DROP FUNCTION / CREATE FUNCTION cycle.

Holds column and domain defaults, constraints, indexes, policies, and trigger conditions around function recreation.
Preserves transaction boundaries while deferring online validation and concurrent index work.
Rejects function recreations involving generated columns or unsafe column default/type transitions.
Preserves the declared state of NOT VALID CHECK constraints.
Adds regression fixtures covering dependent objects, partitions, materialized views, enum changes, and online operations.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart LR
    A[Collect function dependents] --> B[Drop held dependents]
    B --> C[Drop recreated function]
    C --> D[Create updated function]
    D --> E[Restore held dependents]
    E --> F[Validate constraints]
    E --> G[Build new indexes concurrently]

_{Reviews (1) · Last reviewed commit: "fix: recreate non-view dependents around..."}

Copilot

Copilot review overview

🟡 Changes recommended

Dependency handling and NOT VALID preservation still have correctness gaps in supported edge cases.

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Review effort: Balanced
Findings: 1 · 3

Open (4)

Preserve CHECKs referencing recreated columns · New
Process managed trigger dependencies on external tables · New
Preserve case-sensitive domain identities in catalog mapping · New
Exclude invalid CHECKs from inline column emission · New

What changed in this PR

Extends function DROP/CREATE migrations to safely recreate dependent schema objects and preserve NOT VALID CHECK semantics.

Changes:

Holds defaults, constraints, indexes, policies, triggers, domains, and materialized-view indexes around function recreation.
Rejects unsupported generated-column and default-dependent migrations.
Adds transaction-grouping and PostgreSQL integration fixtures.

File	Description
`cmd/plan/plan.go`	Validates unsafe function recreations.
`internal/diff/diff.go`	Integrates dependent holding and ordering.
`internal/diff/function_dependents.go`	Implements dependent collection, recreation, and validation.
`internal/diff/function_dependents_test.go`	Tests recreation validation.
`internal/diff/table.go`	Preserves invalid CHECK state.
`internal/diff/view.go`	Supports deferred materialized-view indexes.
`internal/plan/held_dependents_test.go`	Tests transaction grouping.
`internal/plan/plan.go`	Propagates held-dependent metadata.
`internal/plan/rewrite.go`	Adjusts online rewrites and validation isolation.
`testdata/diff/online/add_check_not_valid/diff.sql`	Expected canonical CHECK DDL.
`testdata/diff/online/add_check_not_valid/new.sql`	Desired invalid CHECK fixture.
`testdata/diff/online/add_check_not_valid/old.sql`	Legacy-row fixture.
`testdata/diff/online/add_check_not_valid/plan.json`	Expected JSON plan.
`testdata/diff/online/add_check_not_valid/plan.sql`	Expected SQL plan.
`testdata/diff/online/add_check_not_valid/plan.txt`	Expected text plan.
`testdata/diff/dependency/issue_601_function_recreate_changed_dependents/diff.sql`	Expected changed-dependent DDL.
`testdata/diff/dependency/issue_601_function_recreate_changed_dependents/new.sql`	Desired changed dependents.
`testdata/diff/dependency/issue_601_function_recreate_changed_dependents/old.sql`	Initial changed-dependent schema.
`testdata/diff/dependency/issue_601_function_recreate_changed_dependents/plan.json`	Expected JSON plan.
`testdata/diff/dependency/issue_601_function_recreate_changed_dependents/plan.sql`	Expected SQL plan.
`testdata/diff/dependency/issue_601_function_recreate_changed_dependents/plan.txt`	Expected text plan.
`testdata/diff/dependency/issue_601_function_recreate_domain_exclude_not_valid/diff.sql`	Expected domain/exclusion DDL.
`testdata/diff/dependency/issue_601_function_recreate_domain_exclude_not_valid/new.sql`	Desired domain dependencies.
`testdata/diff/dependency/issue_601_function_recreate_domain_exclude_not_valid/old.sql`	Initial domain dependencies.
`testdata/diff/dependency/issue_601_function_recreate_domain_exclude_not_valid/plan.json`	Expected JSON plan.
`testdata/diff/dependency/issue_601_function_recreate_domain_exclude_not_valid/plan.sql`	Expected SQL plan.
`testdata/diff/dependency/issue_601_function_recreate_domain_exclude_not_valid/plan.txt`	Expected text plan.
`testdata/diff/dependency/issue_601_function_recreate_partitioned_table/diff.sql`	Expected partitioned-table DDL.
`testdata/diff/dependency/issue_601_function_recreate_partitioned_table/new.sql`	Desired partition dependencies.
`testdata/diff/dependency/issue_601_function_recreate_partitioned_table/old.sql`	Initial partition dependencies.
`testdata/diff/dependency/issue_601_function_recreate_partitioned_table/plan.json`	Expected JSON plan.
`testdata/diff/dependency/issue_601_function_recreate_partitioned_table/plan.sql`	Expected SQL plan.
`testdata/diff/dependency/issue_601_function_recreate_partitioned_table/plan.txt`	Expected text plan.
`testdata/diff/dependency/issue_601_function_recreate_trigger_with_online_steps/diff.sql`	Expected trigger/online DDL.
`testdata/diff/dependency/issue_601_function_recreate_trigger_with_online_steps/new.sql`	Desired trigger dependencies.
`testdata/diff/dependency/issue_601_function_recreate_trigger_with_online_steps/old.sql`	Initial trigger dependencies.
`testdata/diff/dependency/issue_601_function_recreate_trigger_with_online_steps/plan.json`	Expected JSON plan.
`testdata/diff/dependency/issue_601_function_recreate_trigger_with_online_steps/plan.sql`	Expected SQL plan.
`testdata/diff/dependency/issue_601_function_recreate_trigger_with_online_steps/plan.txt`	Expected text plan.
`testdata/diff/dependency/issue_601_function_recreate_unchanged_dependents/diff.sql`	Expected unchanged-dependent DDL.
`testdata/diff/dependency/issue_601_function_recreate_unchanged_dependents/new.sql`	Desired unchanged dependents.
`testdata/diff/dependency/issue_601_function_recreate_unchanged_dependents/old.sql`	Initial unchanged dependents.
`testdata/diff/dependency/issue_601_function_recreate_unchanged_dependents/plan.json`	Expected JSON plan.
`testdata/diff/dependency/issue_601_function_recreate_unchanged_dependents/plan.sql`	Expected SQL plan.
`testdata/diff/dependency/issue_601_function_recreate_unchanged_dependents/plan.txt`	Expected text plan.
`testdata/diff/dependency/issue_601_function_recreate_with_enum_value/diff.sql`	Expected enum-ordering DDL.
`testdata/diff/dependency/issue_601_function_recreate_with_enum_value/new.sql`	Desired enum dependency state.
`testdata/diff/dependency/issue_601_function_recreate_with_enum_value/old.sql`	Initial enum dependency state.
`testdata/diff/dependency/issue_601_function_recreate_with_enum_value/plan.json`	Expected JSON plan.
`testdata/diff/dependency/issue_601_function_recreate_with_enum_value/plan.sql`	Expected SQL plan.
`testdata/diff/dependency/issue_601_function_recreate_with_enum_value/plan.txt`	Expected text plan.
`testdata/diff/dependency/issue_601_function_recreate_with_matview_index_change/diff.sql`	Expected materialized-view index DDL.
`testdata/diff/dependency/issue_601_function_recreate_with_matview_index_change/new.sql`	Desired materialized-view index state.
`testdata/diff/dependency/issue_601_function_recreate_with_matview_index_change/old.sql`	Initial materialized-view state.
`testdata/diff/dependency/issue_601_function_recreate_with_matview_index_change/plan.json`	Expected JSON plan.
`testdata/diff/dependency/issue_601_function_recreate_with_matview_index_change/plan.sql`	Expected SQL plan.
`testdata/diff/dependency/issue_601_function_recreate_with_matview_index_change/plan.txt`	Expected text plan.
`testdata/diff/dependency/issue_601_function_recreate_with_table_online_steps/diff.sql`	Expected table-online DDL.
`testdata/diff/dependency/issue_601_function_recreate_with_table_online_steps/new.sql`	Desired table-online state.
`testdata/diff/dependency/issue_601_function_recreate_with_table_online_steps/old.sql`	Initial table-online state.
`testdata/diff/dependency/issue_601_function_recreate_with_table_online_steps/plan.json`	Expected JSON plan.
`testdata/diff/dependency/issue_601_function_recreate_with_table_online_steps/plan.sql`	Expected SQL plan.
`testdata/diff/dependency/issue_601_function_recreate_with_table_online_steps/plan.txt`	Expected text plan.

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+	td.AddedConstraints = removeByName(td.AddedConstraints, constraints, func(c *ir.Constraint) string { return c.Name })
+	td.ModifiedConstraints = removeByName(td.ModifiedConstraints, constraints, func(c *ConstraintDiff) string { return c.New.Name })
+	earlyConstraints := make(map[string]bool)
+	for _, c := range td.DroppedConstraints {
+		if constraints[c.Name] && exclusionReferencesColumns(c, td.RecreatedColumns) {
+			earlyConstraints[c.Name] = true
+		}
+	}
+	td.DroppedConstraints = removeByName(td.DroppedConstraints, subtract(constraints, earlyConstraints), func(c *ir.Constraint) string { return c.Name })


+		oldTable := oldTables[key]
+		if newTable.IsExternal || (oldTable != nil && oldTable.IsExternal) {
+			continue


+	domains := make(map[string]*ir.Type)
+	for _, dbSchema := range newIR.Schemas {
+		for _, typ := range dbSchema.Types {
+			if typ.Kind == ir.TypeKindDomain {
+				domains[strings.ToLower(typ.Schema+"."+typ.Name)] = typ
+			}


+			if !constraint.IsValid {
+				suffix += " NOT VALID"
+			}


tianzhou requested a balanced review from Copilot September 24, 2026 02:27

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fix: recreate non-view dependents around a function DROP + CREATE (#601) - #622

fix: recreate non-view dependents around a function DROP + CREATE (#601)#622
christophostertag wants to merge 1 commit into
pgplex:mainfrom
christophostertag:fix-function-recreate-dependents-601

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christophostertag commented Sep 24, 2026

Summary

Changes

Behavior change: CHECK constraints declared NOT VALID

Known limitations

Test plan

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greptile-apps Bot commented Sep 24, 2026

Confidence Score: 5/5

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🟡 Changes recommended

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