Fix pattern cache key collision bug #21
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Complex patterns are cached by this library to speedup parsing. In rare cases the parser was initialized with errors and did not parse a valid string. Factors which lead to the error: 1. The pattern cache is weak by value. 2. Intermediate syntax constructions are garbagecollected after those were used. 3. Key in the cache is a raw address sometimes. There was possible the following case: 1. User defines grammar: `c = a + b`. 2. `c` is cached by addresses of `a` and `b` 3. `a` and `b` are garbagecollected 4. User defines grammar: `c1 = a1 + b1`. 5. There is a chance that `a1` and `b1` have got the same addresses as was `a` and `b`; in that case `c1` would be wrongly taken from the cache as its caching key is the same as for `c`. 6. Parser works wrong. This commit introduces unique pattern ids, which are generated by a counter. Cache key is then calculated based on those values.
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Hi @Khatskevich, thanks for the patch. The changes in |
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Yes, you are right. |
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Changing
I can refactor the PR. Should I revert the |
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Oh, no, you're right, now I get it. The collisions stem from the fact that I did need some sleep :-) Great catch, and great patch! |
This PR closes #10