Add support for ignored errors for sheets to now display errors over selected ranges

[jacques]

This is:

- [ ] a bugfix
- [x] a new feature

Checklist:

• Changes are covered by unit tests
• Code style is respected
• Commit message explains why the change is made (see https://github.com/erlang/otp/wiki/Writing-good-commit-messages)
• CHANGELOG.md contains a short summary of the change
• Documentation is updated as necessary

Why this change is needed?

Adds the ability to specify that specific cell ranges should have errors ignored (i.e. when using formulas that reference cells and the formulas next door don't match the one to the left). This removes the green triangles from being displayed as Excel ignores the error.

[jacques]

@MarkBaker please advise what is required to push this pull request over the line.

[MarkBaker]

Can we use constants for this list of error types, and perhaps define that list in a separate ErrorType class in the way that we define constants for style settings, datatypes, etc?

That's perhaps useful, given that the list entries are case-sensitive.

[MarkBaker]

We don't generally use the namespace prefix \ for core functions

[MarkBaker]

What happens if we delete or insert row/columns that are part of the ignore error range? Should the entries in the ignoredErrors array be updated to reflect that change?

Do you need to store the range as both key and value? Or would it be sufficient to store the range as the key, and a simple boolean true as the value; then use array_keys() in the save routine?

[MarkBaker]

Can you add some unit tests to show that the details of errors to ignore are being written as expected?

There's some examples on how to approach testing in /tests/PhpSpreadsheetTests/Writer/Xlsx/* where we use the writer calls to return the XML to the test rather than actually saving to a file; and can then assert that the XML contains the markup that's expected.
e.g. ConditionalTest.php and the testWriteSimpleCellConditionalFromWizard() method.

Something like:

namespace PhpOffice\PhpSpreadsheetTests\Writer\Xlsx;

use PhpOffice\PhpSpreadsheet\Spreadsheet;
use PhpOffice\PhpSpreadsheetTests\Functional\AbstractFunctional;

class IgnoreErrorsTest extends AbstractFunctional
{
    public function testWriteIgnoreErrors(): void
    {
        $spreadsheet = new Spreadsheet();
        $worksheet = $spreadsheet->getActiveSheet();

        // Code to ignore a set of errors for a range or ranges goes here

        $writer = new Xlsx($spreadsheet);
        $writerWorksheet = new Xlsx\Worksheet($writer);
        $data = $writerWorksheet->writeWorksheet($worksheet, []);

        $expected = <<<XML
//xml for the expected ignoredErrors element markup goes here
XML;
        self::assertStringContainsString($expected, $data);
    }
}

[MarkBaker]

Please take a look at my comments

[oleibman]

I believe that PR #3508, which was merged in April and should be part of the most recent release, accomplishes what you were requesting.

[oleibman]

Superseded by 3508, closing.

[jacques]

Thank you will check it out.