Line width size assistant fails to load values when column is name "LENGTH"

[qgib]

Author Name: Paolo Cavallini (@pcav)
Original Redmine Issue: 14258
Affected QGIS version: master
Redmine category:symbology

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The assistant fails to load values of a variable (length, real) from a particular layer.
Other variables (integers, strings) are loaded.

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• strade.zip (Paolo Cavallini)

[qgib]

Author Name: Paolo Cavallini (@pcav)

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• 9557 was configured as strade.zip

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• strade.zip (Paolo Cavallini)

[qgib]

Author Name: Giovanni Manghi (@gioman)

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it works if you use the same datatype but use a different column name... "LENGTH" looks like a reserved word.

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• status_id was changed from Open to Feedback

[qgib]

Author Name: Paolo Cavallini (@pcav)

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Good point. However, LENGTH is a valid column name in DBF, and I do not think we should impose additional limitations.

[qgib]

Author Name: Giovanni Manghi (@gioman)

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Paolo Cavallini wrote:

Good point. However, LENGTH is a valid column name in DBF, and I do not think we should impose additional limitations.

It is a bad practice anyway, I would not be contrary having QGIS not creating columns after any reserved word.

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• os_version was changed from Sid to
• subject was changed from Line width size assistant fails to load values to Line width size assistant fails to load values when column is name "LENGTH"
• status_id was changed from Feedback to Open
• operating_system was changed from Debian to

[qgib]

Author Name: Regis Haubourg (@haubourg)

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I think it is related to #22253. Can you test adding double quotes on field name "LENGTH" manually the size expression generated?

[qgib]

Author Name: Paolo Cavallini (@pcav)

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I confirm that with quotes the expression is valid. I cannot check whether variable content is recognized.
I do not agree calling length (or area, etc.) is bad practice: field calc automatically add it.

[qgib]

Author Name: Regis Haubourg (@haubourg)

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Well, if postgres can be a reference implementation of SQL for us, user fields name is illegal as a SQL keyword when "user" is legal.
Can we just focus on QGIS quoting correctly field names with capitalized , special characters or reserved keywords ?

[qgib]

Author Name: Giovanni Manghi (@gioman)

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duplicate of #22253

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• status_id was changed from Open to Closed
• resolution was changed from to duplicate

[qgib]

Author Name: Paolo Cavallini (@pcav)

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Duplication is possible, but AFAIK not demonstrated. Better leave it open and close it after fix of #22253 and verification.

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• status_id was changed from Closed to Reopened
• resolution was changed from duplicate to

[qgib]

Author Name: Giovanni Manghi (@gioman)

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• easy_fix was configured as 0
• regression was configured as 0

[qgib]

Author Name: Paolo Cavallini (@pcav)

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Fixed now. Tested in QGIS 3.

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• status_id was changed from Reopened to Closed
• description was changed from The assistant fails to load values of a variable (length, real) from a particular layer.
  Other variables (integers, strings) are loaded. to The assistant fails to load values of a variable (length, real) from a particular layer.
  Other variables (integers, strings) are loaded.
• resolution was changed from to fixed/implemented