Bug 6329 – Out of range exceptions not thrown in certain cases

import std.stdio; import std.file; void main() { foreach (string entry; dirEntries(".", SpanMode.shallow)) { writeln(entry[0..1000]); // out of range } } DMD 2.053: D:\>dmd test.d && test.exe core.exception.RangeError@test(8): Range violation DMD 2.054: D:\>dmd test.d && test.exe D:\> Wheres the range error??

As I posted on the newsgroup: It sounds like standard crash dialogs are disabled on your system (or the problem somehow manifests differently for you). But the cause is the same. *** This issue has been marked as a duplicate of issue 6308 ***

Created attachment 1022 Error messages 2.055 still prints out excessive error messages.

(In reply to comment #2) > Created an attachment (id=1022) [details] > Error messages > > 2.055 still prints out excessive error messages. I'm sorry, not "still", this is new behavior.

It doesn't happen on my machine. Have you updated DMD/Phobos/Druntime properly?

Never mind, it only happens when you don't use -g.

Typically I install DMD fresh to make sure I didn't screw something up while updating. I can confirm adding -g removes the access violations.

Here's more issues, this time the sample tries to write to a file handle that was opened in read-only mode: import std.stdio; import std.file; void main() { foreach (string entry; dirEntries(".", SpanMode.shallow)) { auto file = File(entry, "r"); string[] lines; foreach (line; file.byLine) { lines ~= line.idup; } foreach (line; lines) { file.writeln("asdf"); } } } $ dmd test.d && test.exe Nothing is outputted. But with -g: $ dmd -g test.d && test.exe $ std.exception.ErrnoException@D:\DMD\dmd2\windows\bin\..\..\src\phobos\std\stdio.d(1164): (No error) So without the symbolic info I get nothing in stdout. However If I change the sample to this: import std.stdio; import std.file; void main() { foreach (string entry; dirEntries(".", SpanMode.shallow)) { auto file = File(entry, "r"); file.writeln("asdf"); } } $ dmd test.d && test.exe object.Error: Access Violation .. and this error message will loop forever. But with -g I only get one error message as it should be: $ dmd -g test.d && test.exe $ std.exception.ErrnoException@D:\DMD\dmd2\windows\bin\..\..\src\phobos\std\stdio.d(1164): (No error) So I'll just have to compile with -g all the time until this gets resolved.

This is a druntime issue.

(In reply to comment #0) > import std.stdio; > import std.file; > void main() > { > foreach (string entry; dirEntries(".", SpanMode.shallow)) > { > writeln(entry[0..1000]); // out of range > } > } > DMD 2.053: > D:\>dmd test.d && test.exe > core.exception.RangeError@test(8): Range violation > DMD 2.054: > D:\>dmd test.d && test.exe > D:\> > Wheres the range error?? The range error is 'entry' is a string, and you are slicing it beyond it's end. This is not a bug in the compiler or runtime, it's in your code.

(In reply to comment #9) > The range error is 'entry' is a string, and you are slicing it beyond it's end. > This is not a bug in the compiler or runtime, it's in your code. You have misunderstood the bug report. The problem is that, to the user, the exception was silently discarded 2.054. In reality, the range exception results in an uncaught SEH exception. On most machines, it will cause the standard "Program has stopped working" dialog, however Andrej has those dialogs disabled. With DMD 2.058, it causes a barrage of Access Violation errors. This is a bug, as the correct behavior is to print the stack trace of a RangeError and exit.

I've run into this issue yet again. And I've noticed something: If I compile with '-g' then I get the exception thrown. Otherwise nothing is thrown and I get back an exit code: -1073741819 Here's an example with Vladimir's AE library: Use this test.xml file: <Class file="somefile"></Class> And this script: import ae.utils.xml; import std.path; import std.file; import std.stream; import std.stdio; void main() { foreach (string entry; dirEntries(".", SpanMode.shallow)) { if (entry.extension == ".xml") { Stream stream = new BufferedFile(entry); XmlNode document = new XmlDocument(stream); auto node = document.children[0]; writeln(node.attributes["file"]); writeln(node.attributes["none"]); } } } Notice that "file" will exist but "none" does not, and this should throw a RangeError. So if I run 'rdmd -g test.d', I get: core.exception.RangeError@test(20): Range violation and a stack trace. But if I run 'rdmd test.d' (without -g) I get the exit code '-1073741819'. I can't even catch the error by using Throwable, it simply exits the app altogether. As it stands using dirEntries is completely unreliable for me, and this issue keeps shooting me in the foot because I keep forgetting about it as I innocently use the foreach loop without thinking. And here's a way to force the range error without using -g: import ae.utils.xml; import std.path; import std.file; import std.stream; import std.stdio; void main() { string[] entries; foreach (string entry; dirEntries(".", SpanMode.shallow)) { if (entry.extension == ".xml") { entries ~= entry; } } foreach (entry; entries) { Stream stream = new BufferedFile(entry); XmlNode document = new XmlDocument(stream); auto node = document.children[0]; writeln(node.attributes["file"]); writeln(node.attributes["nonexistent_key"]); } } So basically the only safe way of using dirEntries is to save a list of files and then do another foreach loop to process it. I really hope we get this fixed. :/

Did you notice that the return code -1073741819 is 0xC0000005, which usually means "Access Violation"? I guess this is happening in the stack trace generation code that is executed when an exception is thrown. This code is expensive, has to deal with non-existing or buggy debug information and is unsafe itself. I recommend disabling it by default. I usually run this early from a shared static module constructor to disable it (including always loading dbghelp.dll and debug symbols at startup): extern extern(C) __gshared ModuleInfo D4core3sys7windows10stacktrace12__ModuleInfoZ; void disableStacktrace() { ModuleInfo* info = &D4core3sys7windows10stacktrace12__ModuleInfoZ; *cast(typeof(info.o.ctor)*)(cast(void*)info + 8) = null; }

The problem seems solved with 2.059 Win32. I can see the errors with or without -g.

On 2.059 Windows and Linux 32 bit, the problem seems solved. However the (No error) message is uninformative.

(In reply to comment #13) > The problem seems solved with 2.059 Win32. > I can see the errors with or without -g. I don't think it's solved, the dirEntries function was changed between releases so now it doesn't trigger the bug.

It may not be solved, but I think that keeping a bug open with no up to date repro is pointless. By all means, let's reopen the bug if a repro is found again, but until then, I think it's reasonable to close this.

See http://forum.dlang.org/thread/[email protected]

This bug has been fixed last year: https://github.com/D-Programming-Language/dmd/pull/2286 *** This issue has been marked as a duplicate of issue 8563 ***