Suppress search results if search string is too short

Fixes #2603

core/language/en-GB/Search.multids

@@ -8,6 +8,7 @@ Matches: //<small><<resultCount>> matches</small>//
 Matches/All: All matches:
 Matches/Title: Title matches:
 Search: Search
+Search/TooShort: Search text too short
 Shadows/Caption: Shadows
 Shadows/Hint: Search for shadow tiddlers
 Shadows/Matches: //<small><<resultCount>> matches</small>//

core/ui/AdvancedSearch/Shadows.tid

@@ -21,6 +21,8 @@ caption: {{$:/language/Search/Shadows/Caption}}
 
 <$reveal state="$:/temp/advancedsearch" type="nomatch" text="">
 
+<$list filter="[{$:/temp/advancedsearch}minlength{$:/config/Search/MinLength}limit[1]]" emptyMessage="""<div class="tc-search-results">{{$:/language/Search/Search/TooShort}}</div>""" variable="listItem">
+
 <$set name="resultCount" value="""<$count filter="[all[shadows]search{$:/temp/advancedsearch}] -[[$:/temp/advancedsearch]]"/>""">
 
 <div class="tc-search-results">
@@ -33,6 +35,8 @@ caption: {{$:/language/Search/Shadows/Caption}}
 
 </$set>
 
+</$list>
+
 </$reveal>
 
 <$reveal state="$:/temp/advancedsearch" type="match" text="">

core/ui/AdvancedSearch/Standard.tid

@@ -20,6 +20,7 @@ caption: {{$:/language/Search/Standard/Caption}}
 </$linkcatcher>
 
 <$reveal state="$:/temp/advancedsearch" type="nomatch" text="">
+<$list filter="[{$:/temp/advancedsearch}minlength{$:/config/Search/MinLength}limit[1]]" emptyMessage="""<div class="tc-search-results">{{$:/language/Search/Search/TooShort}}</div>""" variable="listItem">
 <$set name="searchTiddler" value="$:/temp/advancedsearch">
 <$list filter="[all[shadows+tiddlers]tag[$:/tags/SearchResults]!has[draft.of]butfirst[]limit[1]]" emptyMessage="""
 <$list filter="[all[shadows+tiddlers]tag[$:/tags/SearchResults]!has[draft.of]]">
@@ -29,4 +30,5 @@ caption: {{$:/language/Search/Standard/Caption}}
 <$macrocall $name="tabs" tabsList="[all[shadows+tiddlers]tag[$:/tags/SearchResults]!has[draft.of]]" default={{$:/config/SearchResults/Default}}/>
 </$list>
 </$set>
+</$list>
 </$reveal>

core/ui/AdvancedSearch/System.tid

@@ -21,6 +21,8 @@ caption: {{$:/language/Search/System/Caption}}
 
 <$reveal state="$:/temp/advancedsearch" type="nomatch" text="">
 
+<$list filter="[{$:/temp/advancedsearch}minlength{$:/config/Search/MinLength}limit[1]]" emptyMessage="""<div class="tc-search-results">{{$:/language/Search/Search/TooShort}}</div>""" variable="listItem">
+
 <$set name="resultCount" value="""<$count filter="[is[system]search{$:/temp/advancedsearch}] -[[$:/temp/advancedsearch]]"/>""">
 
 <div class="tc-search-results">
@@ -33,6 +35,8 @@ caption: {{$:/language/Search/System/Caption}}
 
 </$set>
 
+</$list>
+
 </$reveal>
 
 <$reveal state="$:/temp/advancedsearch" type="match" text="">

core/ui/SideBarLists.tid

@@ -17,9 +17,12 @@ title: $:/core/ui/SideBarLists
 {{$:/core/images/close-button}}
 </$button>
 <$button popup=<<qualify "$:/state/popup/search-dropdown">> class="tc-btn-invisible">
+{{$:/core/images/down-arrow}}
+<$list filter="[{$:/temp/search}minlength{$:/config/Search/MinLength}limit[1]]" variable="listItem">
 <$set name="resultCount" value="""<$count filter="[!is[system]search{$(searchTiddler)$}]"/>""">
-{{$:/core/images/down-arrow}} {{$:/language/Search/Matches}}
+{{$:/language/Search/Matches}}
 </$set>
+</$list>
 </$button>
 </$reveal>
 <$reveal state="$:/temp/search" type="match" text="">
@@ -33,8 +36,12 @@ title: $:/core/ui/SideBarLists
 
 <$reveal tag="div" class="tc-block-dropdown tc-search-drop-down tc-popup-handle" state=<<qualify "$:/state/popup/search-dropdown">> type="nomatch" text="" default="">
 
+<$list filter="[{$:/temp/search}minlength{$:/config/Search/MinLength}limit[1]]" emptyMessage="""<div class="tc-search-results">{{$:/language/Search/Search/TooShort}}</div>""" variable="listItem">
+
 {{$:/core/ui/SearchResults}}
 
+</$list>
+
 </$reveal>
 
 </$reveal>

core/wiki/config/SearchMinLength.tid

@@ -0,0 +1,3 @@
+title: $:/config/Search/MinLength
+
+3

editions/tw5.com/tiddlers/hiddensettings/Hidden Setting SearchMinLength.tid

@@ -0,0 +1,11 @@
+created: 20161011074235805
+modified: 20161011074235805
+tags: [[Hidden Settings]]
+title: Hidden Setting: Search Minimum Length
+type: text/vnd.tiddlywiki
+
+<<.from-version "5.1.14">> Controls the minimum length of a search string before results are displayed.
+
+Defaults to "3".
+
+$:/config/Search/MinLength