A little more...

This problem may ultimately be due to something broken in the text being 
displayed. If I look at the funky class comment, it has these runs

a RunArray runs: #(1 35 18 20 3) values: {#() . {a TextFontChange font: 
1} . #() . {a TextEmphasis code: 1} . #()}

The total length of the run sizes is 77, yet the string is only 70 bytes 
long.

If I copy that text out and paste into a workspace, the runs now look like:

a RunArray runs: #(1 35 18 16) values: {#() . {a TextFontChange font: 1} 
. #() . {a TextEmphasis code: 1}}

and the size of the runs matches the size of the string at 70. I wonder 
if other occurrences of this problem might have a similar cause.


On 7/4/18 4:20 PM, David T. Lewis wrote:
> On Wed, Jul 04, 2018 at 03:46:16PM -0400, Bob Arning wrote:
>> Here is a side-by-side comparison with the styled version on the right
>> and the same text unstyled on the left. Note the difference in runStopIndex
>>
> I see it now. Thanks!
>
> Dave
>
>
>> On 7/4/18 2:49 PM, David T. Lewis wrote:
>>> 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
>>>>>
>>>>>
>

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