Regex filters containing a space or \s never match under the default ByWordAny option ("hello world" doesn't match "hello world")

[matt-edmondson]

What's wrong

DoesMatchRegex (TextFilter/TextFilter.cs ~L452) splits the text into words via ExtractTextTokens for ByWordAny/ByWordAll, then runs the regex against each word separately (~L488-496). The pattern isn't split. Since no single word ever contains whitespace, any regex that must match across whitespace (a literal space, \s, a phrase) can never match. Filter/IsMatch default to TextFilterMatchOptions.ByWordAny, so this is the out-of-the-box behavior.

Failure scenario (verified with a console app against the net10.0 build)

TextFilter.IsMatch("hello world", "hello world", TextFilterType.Regex); // False
TextFilter.IsMatch("hello world", "o w",         TextFilterType.Regex); // False

Only ByWholeString matches. In a regex filter box with default options, typing New York or \d+ items hides every item, even though the regex hint says the text must match the pattern.

Suggested fix

Under ByWordAny, also try the pattern against the whole text: regex.IsMatch(text) || tokens.Any(regex.IsMatch). Keeping the per-word check means word-anchored patterns like ^world keep matching. (For ByWordAll the per-word semantics are arguably intended; at minimum document that whitespace-spanning patterns need ByWholeString there.)

Acceptance criteria

• IsMatch("hello world", "hello world", TextFilterType.Regex) and IsMatch("hello world", "o\\sw", TextFilterType.Regex) return true under the defaults.
• Existing per-word regex tests (e.g. ^world matching "hello world" under ByWordAny) still pass.
• The regex timeout still applies to the added whole-text evaluation (see Regex timeout applies per word per item, so one catastrophic-backtracking pattern still freezes Filter() for N seconds (10 items: 10 s) #118 for the existing per-word timeout concern).

[matt-edmondson]

Triage

• Category: Bug
• Priority: High. ByWordAny is the default for Filter/IsMatch, so any regex that spans whitespace (a literal space, \s, a phrase such as New York) hides every item with default options. The regex filter mode is broken out of the box for a common kind of input.
• Area / suggested assignee: TextFilter.DoesMatchRegex and ExtractTextTokens in TextFilter/TextFilter.cs. Owner: @matt-edmondson
• Duplicates / in progress: not a duplicate. Open PRs Let glob * and ? match across / and \ [patch] #119 (glob across separators) and Fold an inline (?i) culture-invariantly too [patch] #121 (culture-invariant inline (?i)) touch the same matcher but don't cover this. It is related to Regex timeout applies per word per item, so one catastrophic-backtracking pattern still freezes Filter() for N seconds (10 items: 10 s) #118: the whole-text evaluation added here must stay under the same timeout budget, so the two fixes would be easiest to land together or in sequence.
• Next step: under ByWordAny, try the whole text first (regex.IsMatch(text) || tokens.Any(regex.IsMatch)). For ByWordAll, either keep the per-word semantics and document that whitespace-spanning patterns need ByWholeString, or apply the same fallback. Add the acceptance tests for "hello world" and "o\\sw", plus a check that ^world still matches under ByWordAny.

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