Fix for bug #7054 (#7092)

* Fix Bug #7054: Reuse of $:/core/ui/EditTemplate/fields broken

This fixes Bug #7054 by creating a new variable
`safeNewFieldValueTiddlerPrefix` that is always set to a valid,
temporary prefix. This variable is used within `$action-deletetiddler`.
If the passed `newFieldValueTiddlerPrefix` variable is empty a new
prefix will be generated by the same logic that creates the original
`newFieldValueTiddlerPrefix` variable.

To be even more defensive, the prefix-filter was prepended with another
prefix filter that limits matches to `$:/temp/NewFieldValue`. This
prevents a bogus but non empty value in `newFieldValueTiddlerPrefix`
to delete arbitrary tiddlers.

* Add a default for `newFieldValueTiddlerPrefix`

This fixes a problem that was identified while fixing bug #7054. If the
tiddler `$:/core/ui/EditTemplate/fields` is transcluded directly and
`newFieldValueTiddlerPrefix` is not set, it will be generated. This
makes sure that this value is defined. It can not be redefined
unconditionally because if this tiddler is transcluded from
`EditTemplate.tid` these two tiddlers must agree on the same prefix
because the clean-up is duplicated between `EditTemplate.tid` and
`fields.tid`.

This would make `safeNewFieldValueTiddlerPrefix` obsolete, but I leave
it in there to make the macros safe and prevent any problems if the
`newFieldValueTiddlerPrefix` is unset by a later change.

core/ui/EditTemplate.tid

@@ -1,7 +1,12 @@
 title: $:/core/ui/EditTemplate
 
-\define delete-edittemplate-state-tiddlers() <$action-deletetiddler $filter="[<newFieldNameTiddler>] [prefix<newFieldValueTiddlerPrefix>] [<newFieldNameInputTiddler>] [<newFieldNameSelectionTiddler>] [<newTagNameTiddler>] [<newTagNameInputTiddler>] [<newTagNameSelectionTiddler>] [<typeInputTiddler>] [<typeSelectionTiddler>]"/>
+\define delete-edittemplate-state-tiddlers()
+<$set name="safeNewFieldValueTiddlerPrefix" value=<<newFieldValueTiddlerPrefix>> emptyValue=<<qualify "$:/temp/NewFieldValue">> >
+	<$action-deletetiddler $filter="[<newFieldNameTiddler>] [prefix[$:/temp/NewFieldValue]prefix<safeNewFieldValueTiddlerPrefix>] [<newFieldNameInputTiddler>] [<newFieldNameSelectionTiddler>] [<newTagNameTiddler>] [<newTagNameInputTiddler>] [<newTagNameSelectionTiddler>] [<typeInputTiddler>] [<typeSelectionTiddler>]"/>
+</$set>
+\end
 
+<!-- Beware this is duplicated from fields.tid. For details see bug #7054 -->
 \define get-field-value-tiddler-filter() [subfilter<get-field-editor-filter>sha256[16]addprefix[/]addprefix<newFieldValueTiddlerPrefix>]
 \define get-field-editor-filter() [<newFieldNameTiddler>get[text]else[]] :cascade[all[shadows+tiddlers]tag[$:/tags/FieldEditorFilter]!is[draft]get[text]] :and[!is[blank]else{$:/core/ui/EditTemplate/fieldEditor/default}]
 

core/ui/EditTemplate/fields.tid

@@ -10,6 +10,10 @@ $:/config/EditTemplateFields/Visibility/$(currentField)$
 [[hide]] -[title{$(config-title)$}]
 \end
 
+<!-- Beware this is duplicated from EditTemplate.tid. For details see bug #7054 -->
+\define get-field-value-tiddler-filter() [subfilter<get-field-editor-filter>sha256[16]addprefix[/]addprefix<newFieldValueTiddlerPrefix>]
+\define get-field-editor-filter() [<newFieldNameTiddler>get[text]else[]] :cascade[all[shadows+tiddlers]tag[$:/tags/FieldEditorFilter]!is[draft]get[text]] :and[!is[blank]else{$:/core/ui/EditTemplate/fieldEditor/default}]
+
 \define current-tiddler-new-field-selector()
 [data-tiddler-title="$(currentTiddlerCSSescaped)$"] .tc-edit-field-add-name-wrapper input
 \end
@@ -17,7 +21,9 @@ $:/config/EditTemplateFields/Visibility/$(currentField)$
 \define new-field-actions()
 \whitespace trim
 <$action-sendmessage $message="tm-add-field" $name={{{ [<newFieldNameTiddler>get[text]] }}} $value={{{ [<newFieldNameTiddler>get[text]] :map[subfilter<get-field-value-tiddler-filter>get[text]] }}}/>
-<$action-deletetiddler $filter="[<newFieldNameTiddler>] [prefix<newFieldValueTiddlerPrefix>] [<storeTitle>] [<searchListState>]"/>
+<$set name="safeNewFieldValueTiddlerPrefix" value=<<newFieldValueTiddlerPrefix>> emptyValue=<<qualify "$:/temp/NewFieldValue">> >
+	<$action-deletetiddler $filter="[<newFieldNameTiddler>] [prefix[$:/temp/NewFieldValue]prefix<safeNewFieldValueTiddlerPrefix>] [<storeTitle>] [<searchListState>]"/>
+</$set>
 <$action-sendmessage $message="tm-focus-selector" $param=<<current-tiddler-new-field-selector>>/>
 \end
 
@@ -52,7 +58,9 @@ $:/config/EditTemplateFields/Visibility/$(currentField)$
 <$action-sendmessage $message="tm-add-field"
 $name=<<name>>
 $value={{{ [subfilter<get-field-value-tiddler-filter>get[text]] }}}/>
-<$action-deletetiddler $filter="[<newFieldNameTiddler>] [prefix<newFieldValueTiddlerPrefix>] [<storeTitle>] [<searchListState>]"/>
+<$set name="safeNewFieldValueTiddlerPrefix" value=<<newFieldValueTiddlerPrefix>> emptyValue=<<qualify "$:/temp/NewFieldValue">> >
+	<$action-deletetiddler $filter="[<newFieldNameTiddler>] [prefix[$:/temp/NewFieldValue]prefix<safeNewFieldValueTiddlerPrefix>] [<storeTitle>] [<searchListState>]"/>
+</$set>
 <<lingo Fields/Add/Button>>
 </$button>
 </$reveal>
@@ -65,6 +73,7 @@ $value={{{ [subfilter<get-field-value-tiddler-filter>get[text]] }}}/>
 \end
 \whitespace trim
 
+<$set name="newFieldValueTiddlerPrefix" value=<<newFieldValueTiddlerPrefix>> emptyValue=<<qualify "$:/temp/NewFieldValue">> >
 <div class="tc-edit-fields">
 <table class={{{ [all[current]fields[]] :filter[lookup[$:/config/EditTemplateFields/Visibility/]!match[hide]] +[count[]!match[0]] +[then[tc-edit-fields]] ~[[tc-edit-fields tc-edit-fields-small]] }}}>
 <tbody>
@@ -148,3 +157,4 @@ $value={{{ [subfilter<get-field-value-tiddler-filter>get[text]] }}}/>
 </$vars>
 </div>
 </$fieldmangler>
+</$set>