RE: AI Textconv filter misconfiguration on Windows leads to silent corruption of diff output (ongoing investigation)

On September 1, 2026 4:14 PM, Skybuck Flying wrote:

MORE GOD DAMN PROBLEMS WITH GIT AND CR/LF FILTERS.

I DOWNLOADED/GIT CLONED:

https://github.com/openai/openai-openapi/tree/main

I NOTICED:

https://github.com/openai/openai-openapi/tree/main/assets

WAS CORRUPTED.

(CORRECT DOWNLOAD METHOD USES TO PROVE FILE IS INTACT ON SERVER):

curl -L --output "K:\Delphi\Specifications\OpenAI API\github version 3.1.0 (1
september 2026)\assets\openai-api-referencev2.png"
https://raw.githubusercontent.com/openai/openai-
openapi/master/assets/openai-api-reference.png

GOOD THING I INSPECTED IT JUST OUT OF CURIOSITY.

I IMMEDIATELY EXPECTED GIT FILTER TO BE THE CAUSE.

DIAGNOSIS COMMANDS.

"
Microsoft Windows [Version 10.0.22631.6199]
(c) Microsoft Corporation. All rights reserved.

C:\Users\skybu>git config --global core.autocrlf false

C:\Users\skybu>git config --system core.autocrlf false

C:\Users\skybu>git config --local core.autocrlf
fatal: --local can only be used inside a git repository

C:\Users\skybu>git config --global --get-regexp filter

C:\Users\skybu>git config --local --get-regexp filter
fatal: --local can only be used inside a git repository

C:\Users\skybu>git check-attr -a openai-api-reference.png
fatal: not a git repository (or any of the parent directories): .git

C:\Users\skybu>type .gitattributes
* text diff=lfclean
C:\Users\skybu>git config --global --list core.autocrlf=false core.eol=crlf
core.sshcommand=C:/Windows/System32/OpenSSH/ssh.exe
core.attributesfile=C:\Users\skybu\.gitattributes
user.email=skybuck2000@hotmail.com
user.name=Skybuck Flying
user.signingkey=I:\Informatie\Van mezelf\SSH Keys\PrivateKey\GitSigningKey
gui.recentrepo=V:/FuckingWhore/vite-wallet
cinnabar.version-check=1743733941
credential.http://localhost:3000.provider=generic
includeif.gitdir:V:/AI0001/.path=~/.gitconfigs/.gitconfig-ai0001-v2
includeif.gitdir:V:/AI0002/.path=~/.gitconfigs/.gitconfig-ai0002-v2
includeif.gitdir:V:/AI0003/.path=~/.gitconfigs/.gitconfig-ai0003-v2
includeif.gitdir:V:/AI0004/.path=~/.gitconfigs/.gitconfig-ai0004-v2
includeif.gitdir:V:/AI0005/.path=~/.gitconfigs/.gitconfig-ai0005-v2
includeif.gitdir:V:/AI0006/.path=~/.gitconfigs/.gitconfig-ai0006-v2
includeif.gitdir:V:/AI0007/.path=~/.gitconfigs/.gitconfig-ai0007-v2
includeif.gitdir:V:/AI0008/.path=~/.gitconfigs/.gitconfig-ai0008-v2
includeif.gitdir:V:/AI0009/.path=~/.gitconfigs/.gitconfig-ai0009-v2
includeif.gitdir:V:/AI0010/.path=~/.gitconfigs/.gitconfig-ai0010-v2
includeif.gitdir:V:/AI0011/.path=~/.gitconfigs/.gitconfig-ai0011-v2
includeif.gitdir:V:/AI0012/.path=~/.gitconfigs/.gitconfig-ai0012-v2
includeif.gitdir:V:/AI0013/.path=~/.gitconfigs/.gitconfig-ai0013-v2
includeif.gitdir:V:/AI0014/.path=~/.gitconfigs/.gitconfig-ai0014-v2
includeif.gitdir:V:/AI0015/.path=~/.gitconfigs/.gitconfig-ai0015-v2
includeif.gitdir:V:/AI0016/.path=~/.gitconfigs/.gitconfig-ai0016-v2
includeif.gitdir:V:/AI0017/.path=~/.gitconfigs/.gitconfig-ai0017-v2
includeif.gitdir:V:/AI0018/.path=~/.gitconfigs/.gitconfig-ai0018-v2
includeif.gitdir:V:/AI0019/.path=~/.gitconfigs/.gitconfig-ai0019-v2
includeif.gitdir:V:/AI0020/.path=~/.gitconfigs/.gitconfig-ai0020-v2
includeif.gitdir:V:/AIMain/.path=~/.gitconfigs/.gitconfig-aimain-v2
merge.tool=meld
mergetool.prompt=false
mergetool.keepbackup=false
gpg.format=ssh
commit.gpgsign=true
log.showsignature=true
gpg.ssh.allowedsignersfile=I:/Informatie/Van mezelf/SSH
Keys/GitAllowedSigners/GitAllowedSigners.txt
diff.lfclean.textconv=sed -e s/\\r//
diff.lfclean.binary=false

C:\Users\skybu>git check-attr --all -- openai-api-reference.png
fatal: not a git repository (or any of the parent directories): .git

C:\Users\skybu>
"

HYPOTHESIS BY CO-PILOT AND POSSIBLE FIX:

The **smoking gun is now visible**: your global config + your global attributes file
**are applying a custom diff filter (`lfclean`) to *all files*** — including PNGs.
That is exactly why your Git‑downloaded PNG is corrupted while the curl version is
intact.

Let me break it down cleanly and give you the exact commands to verify every part.

---

## 🎯 Core finding: your global `.gitattributes` is rewriting files You showed:

C:\Users\skybu>type .gitattributes
* text diff=lfclean

This means:

- `*` → **every file**, regardless of type
- `text` → Git treats **every file as text**, even binaries
- `diff=lfclean` → Git applies your custom diff driver
- Your diff driver is defined as:

diff.lfclean.textconv=sed -e s/\\r//
diff.lfclean.binary=false

This forces Git to:

- run `sed -e s/\r//` on files
- treat them as **non‑binary**
- strip carriage returns
- potentially corrupt binary formats (PNG, JPG, ZIP, EXE, DLL, etc.)

Curl does not run Git filters → curl file stays intact.

Git does run filters → Git file becomes corrupted.

This is 100% the cause.

---

## 🧪 Commands to confirm the corruption mechanism

### 1. Check what attributes Git applies to your PNG ``` git check-attr --all -- openai-
api-reference.png ```

Expected output (because of your global `.gitattributes`):

openai-api-reference.png: text: set
openai-api-reference.png: diff: lfclean

If you see this → confirmed.

---

### 2. Check the raw blob stored in Git (to see if corruption happens on checkout)
``` git show HEAD:openai-api-reference.png > raw.png ```

Then compare:

fc /b raw.png openai-api-reference.png

If `raw.png` is intact but the working‑tree file is corrupted → the corruption
happens during checkout due to filters.

---

### 3. Show all filters Git knows about

git config --show-origin --get-regexp diff git config --show-origin --get-regexp filter

You will see your `lfclean` diff driver.

---

### 4. Show your global attributes file path ``` git config --global core.attributesfile

It points to:

C:\Users\skybu\.gitattributes

This file is applied to **every repository** on your system.

---

## 🛠️ How to fix it (choose one)

### Option A — Remove the global `.gitattributes` (recommended) ``` del
C:\Users\skybu\.gitattributes ```

### Option B — Restrict the rule to text files only
Replace:

* text diff=lfclean

With:

*.txt text diff=lfclean
*.pas text diff=lfclean
*.dpr text diff=lfclean

### Option C — Mark binary files correctly
Add:

*.png binary
*.jpg binary
*.zip binary
*.exe binary
*.dll binary

---

## 📌 Why this happened
You created a global `.gitattributes` with:

* text diff=lfclean

This is extremely dangerous because:

- Git thinks **every file is text**
- Git applies your custom diff filter to **every file**
- Binary files get corrupted on checkout

This is why:

- **curl file = correct**
- **git file = corrupted**

---

## 🔍 Want me to help rewrite your `.gitattributes` safely?
I can generate a clean, safe version tailored to your Delphi workflow.
Pick one:

- fix global attributes
- create safe Delphi attributes
- audit all Git filters



Apperently Co-Pilot now has the ability to send e-mails, funny functionality, risky
too ! Expect another melissa ai virus soon ? ;)

Anyway I copy & paste it's reply here in plain text:

Hi Git developers,

I'm writing to report a reproducible corruption issue caused by global Git attributes
and diff filters being applied to binary files during checkout.

Summary of the problem
A PNG file downloaded via Git becomes corrupted, while the same file downloaded
via curl remains intact. The corruption is caused by a global `.gitattributes` file that
marks all files as text and assigns a custom diff driver:

* text diff=lfclean

The diff driver is defined globally as:

diff.lfclean.textconv=sed -e s/\\r//
diff.lfclean.binary=false

This forces Git to treat every file as text and run a textconv filter that strips carriage
returns. When applied to binary formats (PNG, JPG, ZIP, EXE, etc.), the checkout
process produces corrupted files.

Reproduction steps
1. Create a global `.gitattributes` file containing:
  * text diff=lfclean
2. Define the diff driver globally:
  diff.lfclean.textconv=sed -e s/\\r//
  diff.lfclean.binary=false
3. Clone any repository containing binary files.
4. Compare a binary file from the working tree with the raw blob:
  git show HEAD:path/to/file > raw.bin
  fc /b raw.bin path/to/file

The working-tree file differs from the blob, confirming corruption during checkout.

Expected behavior
Binary files should remain untouched unless explicitly marked with filters.

Actual behavior
Git applies the global attributes and diff driver to all files, including binaries, causing
corruption.

Request
I would appreciate guidance on whether Git should:
- Warn users when global attributes force text filters onto binary files, or
- Provide safeguards to prevent textconv filters from being applied to known binary
formats.

Thanks for your time and consideration.

Best regards,
Skybuck

version 2:

Here is the **clean, corrected, plain‑text reply**, in a **single code block**, clearly
explaining:

- the **cause**
- the **solution**
- the **future risks**

You can paste this directly into the Git mailing list.

Hi Git developers,

I want to report an issue where Git corrupts binary files during checkout when a
global .gitattributes file forces all paths to be treated as text and assigns a diff driver.

Cause of the problem
My global attributes file contained the line:

   * text diff=lfclean

Because the pattern "*" matches every file, Git applies "text" and "diff=lfclean" to all
paths, including binary files such as PNGs. The "text" attribute forces Git to treat the
file as text even when its content is clearly binary. The assigned diff driver runs a
textconv filter:

   diff.lfclean.textconv = sed -e s/\r//
   diff.lfclean.binary = false

This causes Git to rewrite the file during checkout, stripping carriage returns from
binary data. As a result, the working-tree version of a PNG differs from the blob
stored in the repository, and the file becomes corrupted. A copy downloaded via
curl remains intact because curl does not apply Git filters.

Reproduction steps
1. Create a global .gitattributes file containing:
      * text diff=lfclean
2. Define the diff driver globally:
      diff.lfclean.textconv=sed -e s/\r//
      diff.lfclean.binary=false
3. Clone any repository containing binary files.
4. Compare the blob with the working-tree file:
      git show HEAD:path/to/file > raw.bin
      fc /b raw.bin path/to/file

The working-tree file is corrupted while the blob is correct.

Solution
Remove the global rule or restrict it to actual text file extensions. For example:

   *.txt text diff=lfclean
   *.pas text diff=lfclean
   *.md  text diff=lfclean

Alternatively, explicitly mark binary formats:

   *.png binary
   *.jpg binary
   *.zip binary
   *.exe binary

Deleting the global .gitattributes file entirely also resolves the issue.

Future risks
Global attribute rules are applied to every repository on the system. Using "*" with
"text" or any filter can silently rewrite binary files, break archives, corrupt
executables, and cause difficult-to-diagnose data loss. Users may not realize that Git
is modifying files during checkout, especially when the corruption is subtle. A
warning or safeguard when "text" is forced globally might help prevent accidental
misuse.

Thanks for your time and consideration.

Just some musings from my own frustration in this area.

Having gone through some similar things, I would ignore CoPilot. There are other words I would use as well but they are not for polite company.

Set autocrlf=input not false. Also it is a good idea to set ignorecase=true and filemode=false on Windows.

Git tends to give preferential treatment to text files, only looking at the first hunk (whatever that might be) looking for non-text characters. CR is text, so a file containing those near the front will probably be consider text unless explicitly marked as binary. If you are sure you have binary files, declare them. Do not assume git will always get it right - although .EXE, .ZIP, .JPG, and .PNG are pretty much always binary.

I am going to assume something there, that the clean/smudge and diff engines are not guaranteed to be subject to autocrlf processing before receiving the files. It might be or might not be, depending on what git feels like doing given the state of the file. You would have to go look in the code on the version you have to be certain, but don't count on it in future.

The other problem you may to face, and I have been there, is that clean/smudge and textconv filters definitely *do not like* binary files if not declared as binary, and sometimes even then. You are dealing with stdin and stdout, so have to know how the filter/textconv is opening the files. I have seen platforms that always open in "r" instead of "rb", which was a problem. I had to hack around that using %f in textconv. I have also seen people write textconv programs without awareness that they might get binary data, and that blows up runtimes badly when you hit a NUL in an input buffer after an fgets() in C.

I wish you luck in your adventure.
Randall