[Thom Chiovoloni (thomcc-work)]

Replace ad-hoc quoting with more robust quoting.

[Copilot]

🟡 Changes recommended

Changed quoting for backslash-bearing substitutions causes schedule mismatches when in-flight instances replay after a binary upgrade, without preserved compatibility or a documented and tested upgrade contract.

1 open issue

• Preserve backslash substitution compatibility across binary upgrades · New

What changed in this PR

This PR hardens SQL literal quoting in pg_durable’s result substitution and upgrade tooling, particularly for values containing backslashes and apostrophes.

Changes:

• Replaces ad-hoc Rust quoting with postgres-protocol escaping.
• Adds quoting, injection-prevention, round-trip, and determinism tests.
• Updates the upgrade lifecycle’s Python quoting helper and tests.

File	Description
tests/​e2e/​sql/​97_literal_quoting.sql	Tests substitution on activity connections with nonstandard string settings.
src/​types.rs	Uses robust literal escaping and adds substitution regression tests.
src/​lib.rs	Updates test quoting and adds PostgreSQL-backed quoting tests.
scripts/​upgrade_lifecycle.py	Escapes backslashes using explicit escape-string literals.
scripts/​test_upgrade_lifecycle.py	Tests the Python literal helper’s escaping behavior.
Cargo.toml	Adds the postgres-protocol dependency.
Cargo.lock	Records the new direct dependency.

_{Review effort: Balanced}

[Copilot]

🔵 Needs a closer look

Missing PostgreSQL-backed quoting tests and real N-1 lifecycle validation leave security-sensitive SQL escaping and durable replay compatibility unverified.

No open issues 🎉

1 resolved since last review

• Preserve backslash substitution compatibility across binary upgrades

_{Review effort: Balanced}

[Copilot]

🔵 Needs a closer look

Replay-sensitive serialization and PostgreSQL quoting and connection-setting changes require real N-1 upgrade lifecycle and integration validation that could not be run in this review environment.

No open issues 🎉

_{Review effort: Balanced}