fix: robustly strip psql meta commands #4177
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@andrewmbenton please review |
This was referenced Nov 10, 2025
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Thanks @ignat980 this looks a much more complete solution than I was expecting |
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@ignat980 if you open this against main I can get this merged. Just make sure to includes Andrew's commits. |
kyleconroy
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Replace naive line-based removal with a single-pass state machine that correctly distinguishes psql meta-commands from backslashes in SQL code, literals, and comments.
The previous implementation would incorrectly strip any line starting with a backslash, breaking valid SQL containing:
- Backslashes in string literals (E'\\n', escape sequences)
- Meta-command text in comments or documentation
- Dollar-quoted function bodies with backslash content
Changes:
- Track parsing state for single quotes, dollar quotes, and block comments
- Only remove backslash commands at true line starts outside any literal context
- Properly handle escaped quotes (''), nested block comments (/* /* */ */)
- Support dollar-quoted tags with identifiers ($tag$...$tag$)
- Add comprehensive test suite covering:
* All documented psql meta-commands (\connect, \set, \d*, etc.)
* String literals with backslashes and nested quotes
* Dollar-quoted blocks with various tag formats
* Nested block comments containing meta-command text
* Edge cases: empty input, whitespace-only, missing newlines
Performance improvements:
- Pre-allocate output buffer with strings.Builder.Grow()
- Single pass eliminates redundant string operations
- Reduces allocations by avoiding intermediate line slice
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@kyleconroy Thanks! I rebased to latest sqlc/main and changed this PR's merge-into branch as sqlc/main. Just waiting on the test CI to finish |
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@kyleconroy bump for visibility - not sure why the CI tests haven't run, maybe you need to push something? |
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fix(compiler): robustly strip psql meta commands without breaking SQL
Implements a single-pass state machine that correctly distinguishes psql meta-commands from backslashes in SQL code, literals, and comments.
This fixes schema parsing failures when files contain psql meta-commands like
\connect,\set,\d, etc., which are PostgreSQL client commands that aren't valid SQL.The Problem
Backslashes can appear in valid SQL:
E'\\n', escape sequences)A naive line-based approach would incorrectly strip these, breaking valid SQL.
Changes
''), nested block comments (/* /* */ */)$tag$...$tag$)\connect,\set,\d*, etc.) See PostgreSQLpsqldocsPerformance improvements
strings.Builder.Grow()Testing
go test ./internal/compilerremovePsqlMetaCommands()Credits
Co-authored-by: Andrew Benton andrew@sqlc.dev
Addresses gbarr's comment in #4082 which closes #4065