Path Completion not working regression

[donho]

Description of the Issue

Path Completion has stopped working seems for quite moment.
It's a regression but it's not due to the removal 2GB restriction.

Steps to Reproduce the Issue

1. Type C:\
2. Choose menu command Edit > Auto-Completion > Path Completion or hit Ctrl-Alt-Space

Expected Behavior

Auto-completion list appears. All the sub-folder of C drive should be in the list.

Actual Behavior

Nothing happens.

Debug Information

Notepad++ v8.3 (64-bit)
Build time : Feb 5 2022 - 19:07:43
Path : C:\Program Files\Notepad++\notepad++.exe
Command Line :
Admin mode : OFF
Local Conf mode : OFF
Cloud Config : OFF
OS Name : Windows 11 (64-bit)
OS Version : 2009
OS Build : 22000.434
Current ANSI codepage : 1252
Plugins : mimeTools.dll NppConverter.dll NppExport.dll

[alankilborn]

I went on a version search to where this feature last worked.
I had to go back to v 6.9 !

[donho]

I had to go back to v 6.9 !

Hmm... It seems very little users use this feature - I searched issue tracker before opening a new one, but I found nothing.

[mpheath]

@donho

Testing autocompletion and path completion is one of tests. I repeatly get these 3 msgboxes using the menu entry

---------------------------
General Exception
---------------------------
std::bad_alloc
---------------------------
OK   
---------------------------


---------------------------
Recovery initiating
---------------------------
Notepad++ will attempt to save any unsaved data. However, dataloss is very likely.
---------------------------
OK   
---------------------------


---------------------------
Recovery success
---------------------------
Notepad++ was able to successfully recover some unsaved documents, or nothing to be saved could be found.

You can find the results at :

C:\Users\Michael\AppData\Local\Temp\\N++RECOV
---------------------------
OK   
---------------------------

and then Notepad++ exits.

With Ctrl+Alt+Space I get

---------------------------
Microsoft Visual C++ Runtime Library
---------------------------

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.

---------------------------
OK   
---------------------------

Click OK and crashs Notepad++.

Strange the different behaviours of menu item to keys. Probably irrelevent if fixed.

---

Added some printf calls to get some information.

Output:

bufSize: '260'
currentPos: '41'
startPos: '-219'

-219 for start position. Negative integer could be a possible reason for crashing.

So added more characters to get position to 3000 in the document and tried again. Path completion works.

const auto startPos = max(0, currentPos - bufSize);

If I change auto to int, no crash and no path autocomplete. If I replace currentPos and bufSize with real integers inside max(), then it works and I see autocomplete. I consider max() does not like intptr_t types as I got GCC to show error: no matching function for call to 'max(int, long long int)' with separate test code. https://cplusplus.com/reference/algorithm/max/ mentions Note that invalid arguments cause undefined behavior. So it might be undefined behaviour with types that max() cannot handle.

sizeof() displays 8 for intptr_t and comparing different byte sizes causes problems, so replace

const auto startPos = max(0, currentPos - bufSize);

with

const long long int startPos = (currentPos >= bufSize) ? (currentPos - bufSize) : 0;

works ok as it avoids directly comparing 4 byte int type with 8 byte int type. long long int is to save precision. auto works too though the compiler probably replaces it with int.

[ozone10]

@mpheath
Notepad++ rather than using std::max is using max macro in windows.h.
I would use intptr_t since for 64 bit it's long long (__int64) and for 32 bit int

[mpheath]

@ozone10

Thanks for the information.
Whether max or std::max, both seem to dislike comparing intptr_t with int or the compiler see the diferent types and will end the compile with warning\error.

This test works good as comparisons are only with intptr_t.

#include <iostream>     // std::cout
#include <algorithm>    // std::max
#include <shlwapi.h>    // MAX_PATH

int main () {
	const intptr_t bufSize = MAX_PATH;
	const intptr_t currentPos = 41;
	const intptr_t zero = 0;
	const auto startPos = std::max(zero, currentPos - bufSize);
	std::cout << startPos << '\n';
}

In AutoCompletion.cpp, changing

const auto startPos = max(0, currentPos - bufSize);

to

const auto startPos = (currentPos > bufSize) ? (currentPos - bufSize) : 0;

or

const intptr_t startPos = (currentPos > bufSize) ? (currentPos - bufSize) : 0;

or

const intptr_t zero = 0;
const auto startPos = max(zero, currentPos - bufSize);

works for me.

If you can trust the compiler, then auto seems OK, though it should be intptr_t if the compiler gets it right unless I am fail to understand.

I changed the ternary >= to > as doing currentPos - bufSize seems meaningless to return 0. The ternary has the benefit of not needing the zero to be declared and assigned a value.