I tried reverting #scanCharactersFrom:to:in:rightX:stopConditions:kern:
to the earlier version (cmm 6/12/2010 11:52), but I still get failures
with cursor and mouse in the class comment text when browsing the FooClient
class. There must be something else going on here, and it is certainly
not obvious to me why it is happening only with the FooClient test
example.

Dave

On Wed, Jul 04, 2018 at 02:10:00PM -0400, Bob Arning wrote:
> perhaps this will help:
> 
> This version does not seem to exhibit the error and it limits stopIndex 
> to the size of the string
> 
> !CharacterScanner methodsFor: 'scanning' stamp: 'cmm 6/12/2010 11:52'!
> scanCharactersFrom: startIndex to: stopIndex in: sourceString rightX: 
> rightX stopConditions: stops kern: kernDelta
> 
> ?????? | startEncoding selector |
> ?????? (sourceString isByteString) ifTrue: [^ self 
> basicScanCharactersFrom: startIndex *to: (stopIndex min: sourceString 
> size)* in: sourceString rightX: rightX stopConditions: stops kern: 
> kernDelta.].
> 
> ?????? (sourceString isWideString) ifTrue: [
> ?????? ?????? startIndex > stopIndex ifTrue: [lastIndex := stopIndex. ^ 
> stops endOfRun].
> ?????? ?????? startEncoding :=?? (sourceString at: startIndex) leadingChar.
> ?????? ?????? selector := EncodedCharSet scanSelectorAt: startEncoding.
> ?????? ?????? ^ self perform: selector withArguments: (Array with: 
> startIndex with: stopIndex with: sourceString with: rightX with: stops 
> with: kernDelta).
> ?????? ].
> 
> ?????? ^ stops endOfRun
> ! !
> 
> This version fails and does not limit the stopIndex.
> 
> !CharacterScanner methodsFor: 'scanning' stamp: 'nice 10/22/2013 20:49'!
> scanCharactersFrom: startIndex to: stopIndex in: sourceString rightX: 
> rightX
> ?????? ^sourceString scanCharactersFrom: startIndex *to: stopIndex* with: 
> self rightX: rightX font: font! !
> 
> 
> On 7/4/18 11:53 AM, David T. Lewis wrote:
> >On Wed, Jul 04, 2018 at 02:35:59PM +0200, karl ramberg wrote:
> >>On Wed, Jul 4, 2018 at 11:10 AM K K Subbu <kksubbu.ml at gmail.com> wrote:
> >>
> >>>On Tuesday 03 July 2018 04:40 AM, Tim Johnson wrote:
> >>>>1. File-in the .cs as attached*.
> >>>>2. In a system browser, click on the class, then click on the [?] button
> >>>>to view class comment.
> >>>>3. Notice the styled text in the comment.
> >>>>4. Click around the comment pane a bit.
> >>>>5. Eventually, see "Error: subscript is out of bounds: 71" appear over
> >>>>and over until you interrupt.
> >>>In step 4, it is sufficient to click once near the bottom of the pane
> >>>when the cursor changes from I-bar to arrow and then wait. This will
> >>>trigger the error, but the error window triggers itself recursively
> >>>around 50 times before stopping and displaying the windows.
> >>>
> >>>I added an assert to catch it before recursion:
> >>>
> >>>     self assert: lastIndex < sourceString size.
> >>>
> >>>The assert window itself throws up another error, but that is a topic
> >>>for another thread ;-).
> >>>
> >>>Regards .. Subbu
> >>Hi,
> >>See class comment i NewParagraph for a hint of what happens.
> >>A empty lineSpan 71 to: 70 is added to the end of the paragraph, when you
> >>double click below the text.
> >>When the character scanner looks for characters outside of the string at
> >>index 71 it cause a recursion.
> >>
> >>Best,
> >>Karl
> >>
> >Good tiip to look at the NewParagraph class comment, there is apparently
> >some left over messiness in here somewhere.
> >
> >Another way to trigger the bug using the test case with FooClient is
> >to position the cursor in the comment pane and use keyboard right cursor
> >to move to the end of the comment. This causes the same bounds error but
> >takes a different path through the code leading to the error.
> >
> >Looking through the stack in a debugger after triggering the error with
> >the mouse, here are a few notes (but no conclusions):
> >
> >On mouseUp: we enter Editor>>selectWord then call 
> >Editor>>selectWordLeftDelimiters:rightDelimiters:
> >which has this:
> >
> >	"Select the whole text when clicking before first or after last 
> >	character"
> >	(here > string size or: [here < 2]) ifTrue: [^self selectFrom: 1 to: 
> >	string size].
> >
> >where string is the 70 character String derived from the Text.
> >
> >At this point we are trying to select from 1 to 70 (the whole string for
> >the entire text) in TextEditor>>selectFrom:to:
> >
> >This calls Editor>>selectInvisiblyFrom:to: and here the stop index is
> >set past the size of the string:
> >
> >   selectInvisiblyFrom: start to: stop
> >      "Select the designated characters, inclusive.  Make no visual 
> >      changes."
> >
> >      self markIndex: start pointIndex: stop + 1
> >
> > From this point we are trying to go from index 1 to index 71 over a string
> >of size 70, and eventually end up with the out of bounds exception.
> >
> >A clue that this might be accumulation of kludges: Looking at senders of
> >selectInvisiblyFrom:to: (such as TextEditor>>addText:event:) shows a number
> >of methods that subtract 1 from the stop index when before calling the 
> >method
> >that adds 1 back to the stop index. This certainly does not have a good 
> >smell.
> >
> >It is not clear to me why selectInvisiblyFrom:to: would be adding one to 
> >the
> >stop index, but I see that the method stamp is jmv 5/27/2011, which 
> >suggests
> >to me that we should take a look at Cuis to figure out how this is intended
> >to function. Cuis does not show any cases of senders of 
> >selectInvisiblyFrom:to:
> >that subtract 1 from the stop index, and the Cuis implementation of
> >selectInvisiblyFrom:to: is that same as Squeak.
> >
> >Dave
> >
> >
> 

>