Diff Upstream Grammar

Check whether the hand-written AST action rules in python/syntaqlite/ast_codegen/ast_actions/*.y are still compatible with the SQLite grammar in third_party/src/sqlite/src/parse.y.

Action file rule signatures must match upstream parse.y exactly. When SQLite updates its grammar, some signatures may change and the action files need updating.

Running the diff

bash

tools/dev/diff-upstream-grammar third_party/src/sqlite/src/parse.y

The tool uses Lemon -g to strip C action code from both grammars, producing clean rule signatures for comparison.

•Exit 0: No rule changes — AST actions are in sync.
•Exit 1: Changes found. The diff output shows added (+) / removed (-) rules. If any changed nonterminals have AST actions, a WARNING lists them with the affected files.

When changes affect AST actions

The warning output names the nonterminals. Find the corresponding action files:

File	Nonterminals
`_common.y`	input, cmdlist, ecmd, cmdx
`select.y`	cmd, select, selectnowith, oneselect, selcollist, sclp, scanpt, as, distinct, from, where_opt, groupby_opt, having_opt, orderby_opt, limit_opt
`expressions.y`	Expression-related rules
`identifiers.y`	nm, ids, identifier rules
`literals.y`	Literal value rules

All files are in python/syntaqlite/ast_codegen/ast_actions/.

Update the rule signatures in the action files to match the new grammar exactly, preserving the C action code.

After fixing action files

Regenerate extracted code and verify:

bash

python3 python/tools/extract_sqlite.py --output-dir src
tools/dev/ninja -C out/mac_debug
out/mac_debug/syntaqlite_unittests
tools/tests/run-ast-diff-tests --binary out/mac_debug/ast_test

Key files

Path	Role
`tools/dev/diff-upstream-grammar`	CLI entry point
`python/tools/diff_upstream_grammar.py`	Implementation
`third_party/src/sqlite/src/parse.y`	Repo's current SQLite grammar
`python/syntaqlite/ast_codegen/ast_actions/*.y`	Hand-written AST action rules
`python/tools/extract_sqlite.py`	Full code regeneration