Array.prototype.join creates unrooted C heap references to ejsvals
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Nobody has claimed this yet.
- Dominant language
- JavaScript
- Stars
- 431
- Forks
- 20
- PR merge metrics
- No merged PRs in 30d
Description
from _ejs_Array_prototype_join:
ejsval* strings = (ejsval*)malloc (sizeof (ejsval) * num_strings);
int i;
for (i = 0; i < num_strings; i ++) {
strings[i] = ToString(EJS_DENSE_ARRAY_ELEMENTS(_this)[i]);
result_len += EJSVAL_TO_STRLEN(strings[i]);
}
If a collection is run during the course of that loop, the strings allocated prior to the allocation causing the collection will become garbage.
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start at _ejs_Array_prototype_join and inspect how the malloc'ed strings array interacts with collection during the loop. Trace the runtime's rooting behavior for each ejsval and determine how to keep earlier converted strings reachable until the join completes. Done means a collection during this loop no longer makes those references garbage.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c, javascript
- Domain
- compilers
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100