More helpful error message in JSON decoder #113047
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While JavaScript typically parses the following example, it is not strictly valid JSON. But while the current Python error message `Expecting property name enclosed in double quotes` hints at a missing quote, the problem in fact is a trailing comma:
```js
{
"key": "value",
}
```
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Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool. If this change has little impact on Python users, wait for a maintainer to apply the |
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Thanks for filing this issue! I had a question but I believe @rhettinger may have thoughts here.
Lib/json/decoder.py
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| @@ -161,7 +161,7 @@ def JSONObject(s_and_end, strict, scan_once, object_hook, object_pairs_hook, | |||
| return pairs, end + 1 | |||
| elif nextchar != '"': | |||
| raise JSONDecodeError( | |||
| "Expecting property name enclosed in double quotes", s, end) | |||
| "Expecting a property name enclosed in double quotes (no trailing comma allowed)", s, end) | |||
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Is there a reason to not have this be handled in a dedicated case with a more specific error message? It kind of seems like we might be burying the lede with the current error message if the trailing comma is the issue.
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It is not so simple.
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Most changes to Python require a NEWS entry. Add one using the blurb_it web app or the blurb command-line tool. If this change has little impact on Python users, wait for a maintainer to apply the |
While JavaScript typically parses the following example, it is not strictly valid JSON. But while the current Python error message
Expecting property name enclosed in double quoteshints at a missing quote, the problem in fact is a trailing comma:The new error message becomes:
Expecting a property name enclosed in double quotes (no trailing comma allowed)I believe this trivial change does neither require a NEWS entry nor a separate issue, but I do not have experience if there are any tools that depend on the exact error message of the exception...