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42 lines
1.8 KiB
Markdown
42 lines
1.8 KiB
Markdown
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How to use Fuzzer
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===
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The fuzzer consists of auto-generated files:
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ClickHouseUnlexer.py
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ClickHouseUnparser.py
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They are generated from grammar files (.g4) using Grammarinator:
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pip3 install grammarinator
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grammarinator-process ClickHouseLexer.g4 ClickHouseParser.g4 -o fuzzer/
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Then you can generate test input for ClickHouse client:
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cd fuzzer
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grammarinator-generate \
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-r query_list \ # top-level rule
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-o /tmp/sql_test_%d.sql \ # template for output test names
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-n 10 \ # number of tests
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-c 0.3 \
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-d 20 \ # depth of recursion
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-p ClickHouseUnparser.py -l ClickHouseUnlexer.py \ # auto-generated unparser and unlexer
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--test-transformers SpaceTransformer.single_line_whitespace \ # transform function to insert whitespace
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For more details see `grammarinator-generate --help`. As a test-transformer function also can be used `SpaceTransformer.multi_line_transformer` - both functions reside in `fuzzer/SpaceTransformer.py` file.
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Parsing steps
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===
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1. Replace all operators with corresponding functions.
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2. Replace all asterisks with columns - if it's inside function call, then expand it as multiple arguments. Warn about undeterministic invocations when functions have positional arguments.
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Old vs. new parser
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===
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- `a as b [c]` - accessing aliased array expression is not possible.
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- `a as b . 1` - accessing aliased tuple expression is not possible.
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- `between a is not null and b` - `between` operator should have lower priority than `is null`.
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- `*.1` - accessing asterisk tuple expression is not possible.
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