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json_pretty inserts formatting inside strings, corrupting values and producing invalid JSON

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
78/100
Issue type
Bug
Clarity
Clearly specified
Activity status
Active
Tech stack
c
Domain
tooling

Research direction

Start with lib/json.eigs:55–94 and run the supplied program through src/eigenscript to observe the corruption. Add regression coverage for punctuation, escaped quotes, backslashes, and nested arrays or objects, using an independent JSON validity check. Done means formatting occurs only outside strings and all string values remain exact; docs/STDLIB.md:488 describes the promised API.

Written by the indexing model from the issue text.

Description

area:stdlib bug found-by:code-review kind:silent-wrong

json.json_pretty inserts indentation inside JSON strings. Valid JSON becomes invalid JSON, and the string value changes if the output is decoded by EigenScript's permissive string decoder.

Reproduce

Save this program and run it with src/eigenscript:

import json
original is "{\"s\":\"a,b\"}"
pretty is json.json_pretty of original
print of pretty
print of (json_encode of (json_decode of pretty))

Actual formatted text:

{
  "s":"a,
  b"
}

Expected: the value remains exactly a,b; formatting whitespace is inserted only outside JSON strings. Python's json.loads rejects the actual text with Invalid control character. EigenScript's decoder accepts the raw newline and re-encodes the changed value as {"s":"a,\n b"}.

Cause and coverage

lib/json.eigs:55–94 reacts to every brace, bracket and comma without tracking whether the current character is inside a JSON string or follows an escape. The public API promises indented JSON output.

No existing test calls json_pretty. Regression cases should preserve exact string values containing punctuation, escaped quotes and backslashes, while still indenting real arrays/objects. Merely checking that EigenScript's decoder accepts the output is insufficient: its permissive decoder accepts this corrupted result. Include an independent JSON validity check or verify that no unescaped control characters were inserted into string tokens.

Confirmed with a fresh default release build of b91768e23c5a874a64e76e4af9ab291e6aa49983, with inherited EIGS_* variables removed.

Dominant language
C
Stars
3
Forks
7
Avg merge
3h 58m
Merged PRs (30d)
105

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