The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘Software Development’ Category

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Fixing hg.exe “ImportError: DLL load failed: %1 is not a valid Win32 application.”

Posted by jpluimers on 2021/07/21

If you get the below error when running hg.exe, then you are mixing a 64-bit Mercurial with 32-bit dependencies:

C:\>hg --version
Traceback (most recent call last):
  File "hg", line 43, in 
  File "hgdemandimport\demandimportpy2.pyc", line 150, in __getattr__
  File "hgdemandimport\demandimportpy2.pyc", line 94, in _load
  File "hgdemandimport\demandimportpy2.pyc", line 43, in _hgextimport
  File "mercurial\dispatch.pyc", line 22, in 
  File "hgdemandimport\demandimportpy2.pyc", line 248, in _demandimport
  File "hgdemandimport\demandimportpy2.pyc", line 43, in _hgextimport
  File "mercurial\i18n.pyc", line 28, in 
  File "hgdemandimport\demandimportpy2.pyc", line 150, in __getattr__
  File "hgdemandimport\demandimportpy2.pyc", line 94, in _load
  File "hgdemandimport\demandimportpy2.pyc", line 43, in _hgextimport
  File "mercurial\encoding.pyc", line 24, in 
  File "mercurial\policy.pyc", line 101, in importmod
  File "mercurial\policy.pyc", line 63, in _importfrom
  File "hgdemandimport\demandimportpy2.pyc", line 164, in __doc__
  File "hgdemandimport\demandimportpy2.pyc", line 94, in _load
  File "hgdemandimport\demandimportpy2.pyc", line 43, in _hgextimport
  File "mercurial\cext\parsers.pyc", line 12, in 
  File "mercurial\cext\parsers.pyc", line 10, in __load
ImportError: DLL load failed: %1 is geen geldige Win32-toepassing.

The equivalent English error is [WayBack] “ImportError: DLL load failed: %1 is not a valid Win32 application.” – Google Search.

The problem is the bitness of hg.exe: [WayBack] python – Error while installing Mercurial on IIS7 64bit: “DLL Load Failed: %1 is not a valid Win32 application” – Stack Overflow

You can quickly figure out the bitness of hg.exe:

C:\>where hg
C:\Program Files\Mercurial\hg.exe

C:\>sigcheck "C:\Program Files\Mercurial\hg.exe"

Sigcheck v2.72 - File version and signature viewer
Copyright (C) 2004-2019 Mark Russinovich
Sysinternals - www.sysinternals.com

c:\program files\mercurial\hg.exe:
        Verified:       Unsigned
        Link date:      17:49 9-7-2019
        Publisher:      n/a
        Company:        n/a
        Description:    Fast scalable distributed SCM (revision control, version control) system
        Product:        mercurial
        Prod version:   5.0.2
        File version:   5.0.2
        MachineType:    64-bit

Forcing x86 of Mercurial

Since I use chocolatey for most my installs, I forced x86 the Chocolatey way:

So after these:

choco uninstall --yes hg
choco install --yes --force86 hg

I got this signature check:

C:\>sigcheck "C:\Program Files (x86)\Mercurial\hg.exe"

Sigcheck v2.72 - File version and signature viewer
Copyright (C) 2004-2019 Mark Russinovich
Sysinternals - www.sysinternals.com

c:\program files (x86)\mercurial\hg.exe:
        Verified:       Unsigned
        Link date:      17:50 9-7-2019
        Publisher:      n/a
        Company:        n/a
        Description:    Fast scalable distributed SCM (revision control, version control) system
        Product:        mercurial
        Prod version:   5.0.2
        File version:   5.0.2
        MachineType:    32-bit

–jeroen

Posted in Development, DVCS - Distributed Version Control, Encoding, Mercurial/Hg, Python, Scripting, Software Development, Source Code Management | Leave a Comment »

Filezilla: figuring out the cause of “Connection timed out after 20 seconds of inactivity”

Posted by jpluimers on 2021/07/21

On one of my Raspberry Pi boxes, somehow I could not access files over SFTP (SSH File Transfer Protocol) via FileZilla.

I would consistently get this error:

"Connection timed out after 20 seconds of inactivity"

Figuring the exact cause took a while.

TL;DR: SFTP uses an interactive non-login shell, then interprets the output from that shell. For that kind of shell, ensure few or none scripts run that output text.

These links finally got me to the cause

Read the rest of this entry »

Posted in *nix, *nix-tools, bash, bash, Communications Development, Conference Topics, Conferences, Development, Event, Internet protocol suite, Power User, Scripting, SFTP, Software Development, SSH, TCP | Leave a Comment »

Some useful FastMM related methods to track memory usage

Posted by jpluimers on 2021/07/21

Below, for my link archive, some searches and relevant posts on FastMM related method calls to track or report memory usage.

Searches:

  • LogMemoryManagerStateToFile
  • FastGetHeapStatus {Returns summarised information about the state of the memory manager. (For
    backward compatibility.)}
  • GetMemoryManagerState (InternalBlockSize, UseableBlockSize, AllocatedBlockCount, ReservedAddressSpace) {Returns statistics about the current state of the memory manager}GetMemoryManagerUsageSummary {Returns a summary of the information returned by GetMemoryManagerState}
  • GetMemoryMap {Non-POSIX only; Gets the state of every 64K block in the 4GB address space}
  • ScanMemoryPoolForCorruptions; {Scans the memory pool for any corruptions. If a corruption is encountered an “Out of Memory” exception is raised.}
    • It is very costly in CPU usage, but helps finding heap corruption quickly.
  • function GetCurrentAllocationGroup: Cardinal;
    • {Returns the current “allocation group”. Whenever a GetMem request is serviced
      in FullDebugMode, the current “allocation group” is stored in the block header.
      This may help with debugging. Note that if a block is subsequently reallocated
      that it keeps its original “allocation group” and “allocation number” (all
      allocations are also numbered sequentially).}
  • procedure PushAllocationGroup(ANewCurrentAllocationGroup: Cardinal);
    procedure PopAllocationGroup;

    • {Allocation groups work in a stack like fashion. Group numbers are pushed onto
      and popped off the stack. Note that the stack size is limited, so every push
      should have a matching pop.}
  • LogAllocatedBlocksToFile
    • {Logs detail about currently allocated memory blocks for the specified range of
      allocation groups. if ALastAllocationGroupToLog is less than
      AFirstAllocationGroupToLog or it is zero, then all allocation groups are
      logged. This routine also checks the memory pool for consistency at the same
      time, raising an “Out of Memory” error if the check fails.}
  • SetMMLogFileName
    • {Specify the full path and name for the filename to be used for logging memory
      errors, etc. If ALogFileName is nil or points to an empty string it will
      revert to the default log file name.}

Posts (note that not all of them get their calculations right):

These help you track leaks that do not appear as leaks during shutdown: memory allocations that will be released at the end of your application, but are mostly unused while your application is still alive.

A few things to take away from these:

  1. “Out of Memory” (or exception EOutOfMemor) could mean that the memory manager structures are hosed, but memory is still available.
  2. You can specify the FastMM log file used (for instance to include a PID or run-time ID in them so each run gets a separate filename)
  3. When carefully setting up allocation groups, you are able to zoom in at allocations

A gist with a MemoryManagerUnit showing a few of these calls is below.

An example of its usage is this:

procedure TMyTestClass.TestMethod();
begin
   TLogMemoryStatesHelper.DumpMemoryStatesBeforeAndAfter('TestMethod',
     TLogging.LogDir,
     TFileLogger.GetLogFileName,
     procedure (const AFormat: string; const Args: array of const)
     begin
       TLogging.LogEvent(ltInfoHigh, aFormat, Args);
     end,
     procedure()
     begin
       try
         // Given
         BuildSomeTestScenario();
         // When
         InitializeTestScenario();
         // Then
         CheckEquals(0, TestScenarioSummary());
       finally
         // Cleanup
         CleanUpTestScenario();
       end;
     end
  );
end;

–jeroen

Read the rest of this entry »

Posted in Delphi, Development, FastMM, Software Development | Leave a Comment »

Very different views on the repository pattern

Posted by jpluimers on 2021/07/20

–jeroen

Read the rest of this entry »

Posted in .NET, Design Patterns, Development, Software Development | Leave a Comment »

Some links for detecting memory leaks from individual DUnit test methods

Posted by jpluimers on 2021/07/20

–jeroen

Posted in Conference Topics, Conferences, Delphi, Development, DUnit, Event, FastMM, Software Development | Leave a Comment »

windows – Is there any sed like utility for cmd.exe? – Stack Overflow

Posted by jpluimers on 2021/07/19

[WayBack] windows – Is there any sed like utility for cmd.exe? – Stack Overflow

TL;DR: many people suggest to use PowerShell, but there is GNU sed in Chocolatey

The chocolatey part:

The PowerShell part: read the other answers from the above question.

–jeroen

Posted in *nix, *nix-tools, CommandLine, Power User, PowerShell, RegEx, sed, Windows | Leave a Comment »

CloudFlare knows how to do public postmortems on outages

Posted by jpluimers on 2021/07/16

Everyone can learn from an outage. CloudFlare shows how to do it right, for instance on the RegEx-going-wild downtime 2 years ago.

So it’s time to link to that one again: [WayBack] Details of the Cloudflare outage on July 2, 2019

More like these at [WayBack] Post Mortem – The Cloudflare Blog.

More on evaluating regular expressions in linear time:

Via [WayBack] Details of the Cloudflare outage on July 2, 2019 | Hacker News

–jeroen

Posted in Algorithms, Development, Power User, RegEx, Software Development | Leave a Comment »

c# – Algorithm to check whether a certain hour falls into a given time period – Stack Overflow

Posted by jpluimers on 2021/07/15

For my link archive: [WayBack] c# – Algorithm to check whether a certain hour falls into a given time period – Stack Overflow answered by [WayBack] kennytm:

Assume you only have the time and not the date.

if end_time >= start_time:
    return start_time <= current_time <= end_time
else:
    return start_time <= current_time or current_time <= end_time

I totally agree with this comment:

This is brilliant! Thanks a lot. – Martin Dimitrov [WayBack]

I love it when algorithms are simple and elegant.

It reminded me of another scheduling related algorithm: [WayBack] Activity Selection Problem | Greedy Algo-1 – GeeksforGeeks

–jeroen

 

Posted in .NET, Algorithms, C#, Development, Software Development | Leave a Comment »

How do I get the application exit code from a Windows command line? – Stack Overflow

Posted by jpluimers on 2021/07/15

[WayBack] How do I get the application exit code from a Windows command line? – Stack Overflow solutions below.

Note they ONLY work when nobody sets the ERRORLEVEL environment variable.

  • You can quickly see what app returns: app.exe & echo %errorlevel% – [WayBack] marbel82
  • something.exe
echo Exit Code is %errorlevel%

    – [WayBack] Samuel Renkert

  • start /wait something.exe
echo %errorlevel%

    – [WayBack] Gary

  • @echo off
my_nify_exe.exe
if %ERRORLEVEL% EQU 0 (
   echo Success
) else (
   echo Failure Reason Given is %errorlevel%
   exit /b %errorlevel%
)

    – [WayBack] Curtis Yallop

  • It’s worth noting that .BAT and .CMD files operate differently.Reading https://ss64.com/nt/errorlevel.html it notes the following:

    There is a key difference between the way .CMD and .BAT batch files set errorlevels:

    An old .BAT batch script running the ‘new’ internal commands: APPEND, ASSOC, PATH, PROMPT, FTYPE and SET will only set ERRORLEVEL if an error occurs. So if you have two commands in the batch script and the first fails, the ERRORLEVEL will remain set even after the second command succeeds.

    This can make debugging a problem BAT script more difficult, a CMD batch script is more consistent and will set ERRORLEVEL after every command that you run .

    This was causing me no end of grief as I was executing successive commands, but the ERRORLEVEL would remain unchanged even in the event of a failure. – [WayBack] RockDoctor

–jeroen

Posted in Batch-Files, Development, Scripting, Software Development | Leave a Comment »

inheritance – Delphi: How to call inherited inherited ancestor? – Stack Overflow

Posted by jpluimers on 2021/07/15

Officially, the answer to [WayBack] inheritance – Delphi: How to call inherited inherited ancestor? – Stack Overflow is that you can’t on the language level as I explained in my answer

You can’t in a regular language way, as this would break the object oriented aspects of the language.

You can fiddle around with pointers and clever casts to do this, but before even starting to answer that: is this really what you want?

As others mentioned: your need sounds like a serious “design smell” (which is similar to code smell, but more severe.

Edit:

Going down the pointer fiddling road might save you work in the short term, and cost you weeks of work in the long term.
This makes for some good reading on that: Upstream decisions, downstream costs.

If you really want, then there is a clever hack around this by [WayBack] User kludg – Stack Overflow.

His hack is centered around understanding what what the [WayBack] System.TMethod Record essentially is:

Read the rest of this entry »

Posted in Conference Topics, Conferences, Delphi, Development, Event, Software Development | Leave a Comment »

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