Remove the 'patch prefix exists, appears to be a -p0 patch' warning
entirely as it is fundamentally flawed and can only produce false
positives.

Sometimes I create test files with names 'a' and 'b', and then get
surprised seeing this warning. It was not easy to understand where it
comes from.

How it works:
1. It extracts prefixes (a/, b/) from standard diff output
2. Checks if files/directories with these names exist in the project
   root
3. Warns if they exist, claiming it's a '-p0 patch' issue

This logic is wrong because:
- Standard diff/patch tools always use a/ and b/ prefixes by default
- The existence of files named 'a' or 'b' in the working directory is
  completely unrelated to patch format
- The working directory state may not correspond to the patch content
  (different commits, branches, etc.)
- In QEMU project, there are no single-letter files/directories in root,
  so this check can only generate false positives

The correct way to detect -p0 patches would be to analyze the path
format within the patch itself (e.g., absolute paths or paths without
prefixes), not check filesystem state.

So, let's finally drop it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]>
---
 scripts/checkpatch.pl | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index d3d75f3f13..d0f4537f25 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1741,13 +1741,7 @@ sub process {
                        }
                } elsif ($line =~ /^\+\+\+\s+(\S+)/) {
                        $realfile = $1;
-                       $realfile =~ s@^([^/]*)/@@ if (!$file);
-
-                       $p1_prefix = $1;
-                       if (!$file && $tree && $p1_prefix ne '' &&
-                           -e "$root/$p1_prefix") {
-                               WARN("patch prefix '$p1_prefix' exists, appears 
to be a -p0 patch\n");
-                       }
+                       $realfile =~ s@^[^/]*/@@  if (!$file);
 
                        if (defined $fileinfo && !$fileinfo->{isgit}) {
                                $fileinfo->{lineend} = $oldhere;
-- 
2.48.1


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