#380 Allow ignoring partial/multiple lines with regexp filter

[Anonymous]

Using WinMerge 2.1.7.1 I have a set of files that
contain lines beginning with /* and ending with */
When the filter is turned off these lines are found to
be different between the two files.
When I add a filter using the regular expression
/\*.?\*/ the filter removes some lines but not lines
where multiple lines are contained in the diff.
You can see this in the attached files and screenshot

[Nobody/Anonymous]

Sample files showing issue.

[ganier]

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This is maybe not what you expect, but this is normal.

WinMerge follows the rules of diffutils.
Lines matching regular expression are ignored only if they are
isolated.
If a line matching regular expression is just before or just
after a not-ignored difference, it is merged with that
difference in a bigger difference.

[Kimmo Varis]

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This is unfortunate side-effect of diffutils. I guess it
tries to 'pack' diffs (for smaller patch files and easier
patching?) and avoids splitting diffs.

But this is not what users expect. I don't like this
behavior either and I think we really should fix this later
in 2.3.

I we'll need better linefiltering and only way to implement
it is doing filtering *before* diffutils. Multi-line or
partial line capable filtering would be a great feature.
Currently there is no way to filter multiline C-style
comments for example.

Should we move this to RFE list?

[Kimmo Varis]

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I'm moving this to RFE about multiline ignores.
New summary: 'Allow ignoring multiple lines with regexp filter'.

[Kimmo Varis]

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Tweaking summary, I think partial/multiple line ignoring is
same thing here... And both would be very handy to have.

[Kimmo Varis]

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Low priority since this seems hard to implement.