Summary
The current error reporting feature truncates long strings and appends an ellipsis (...) to the output. In some scenarios, truncation occurs in the middle of an escaped character sequence, causing the reported content to become syntactically invalid.
Specifically, an escaped double quote (\") can be transformed into \..., resulting in an invalid escape sequence and malformed generated Python code.
Problem Description
The error reporting mechanism stringifies token content before reporting it. When the resulting string exceeds the truncation threshold, the content is automatically shortened and complemented with an ellipsis.
If truncation happens at the location of an escaped double quote, the original sequence:
may be transformed into:
This effectively escapes the ellipsis rather than the original quote character and introduces an invalid symbol sequence into the generated output.
Example
Original token content:
"items_list": [{
"key": "./Header/ItemHeader",
"value": "Some_Value",
"other_value": null
}]
When this token content is stringified for error reporting, the output is truncated.
Because the truncation point occurs at the opening quote of the key value, the generated error-reporting code may contain something similar to:
items_list = <ListElement[]>[
ListElement {
key = \..."
Observed behavior
- Invalid escape sequences are introduced.
- Generated Python code becomes syntactically invalid.
- An exception is raised while handling an earlier initial reporting the original error.
Expected Behavior
String truncation should never alter escape sequences or generate syntactically invalid output.
Impact
- Generated python code can no longer be executed.
- Secondary exceptions obscure the original root cause.
Workaround
As a temporary workaround, I changed the order of fields in the data type instantiation so that the escaped quote was no longer located at the truncation boundary.
This avoids corruption of the escape sequence and prevents the generated Python code from becoming invalid.
Summary
The current error reporting feature truncates long strings and appends an ellipsis (
...) to the output. In some scenarios, truncation occurs in the middle of an escaped character sequence, causing the reported content to become syntactically invalid.Specifically, an escaped double quote (
\") can be transformed into\..., resulting in an invalid escape sequence and malformed generated Python code.Problem Description
The error reporting mechanism stringifies token content before reporting it. When the resulting string exceeds the truncation threshold, the content is automatically shortened and complemented with an ellipsis.
If truncation happens at the location of an escaped double quote, the original sequence:
may be transformed into:
This effectively escapes the ellipsis rather than the original quote character and introduces an invalid symbol sequence into the generated output.
Example
Original token content:
When this token content is stringified for error reporting, the output is truncated.
Because the truncation point occurs at the opening quote of the
keyvalue, the generated error-reporting code may contain something similar to:Observed behavior
Expected Behavior
String truncation should never alter escape sequences or generate syntactically invalid output.
Impact
Workaround
As a temporary workaround, I changed the order of fields in the data type instantiation so that the escaped quote was no longer located at the truncation boundary.
This avoids corruption of the escape sequence and prevents the generated Python code from becoming invalid.