[janedbal]

Git writes \ No newline at end of file after a line that has no newline. sebastian/diff parses this marker as an unchanged line, so PatchParser counts it as a line of the new file. Every added line after the marker gets a number one too high:

@@ -1,3 +1,4 @@
 parameters:
     paths:
-        - src
\ No newline at end of file      ← counted as line 3
+        - src                    ← gets #4, real line is 3
+        - tests                  ← gets #5, real line is 4

The content check then fails, and check --patch and patch-coverage stop:

⚠️  Error: Patch file 'neon.patch' has added line #4 that does not match actual content of file '…/phpstan.neon'.
Patch data: '        - src'
Filesystem: '        - tests'

Is the patch up-to-date?

When it happens:

• The old version of a file has no final newline, and the change adds lines after its last line or edits its last line.
• Adding the missing final newline is enough, e.g. a phpcbf fix.
• The check covers every file in the patch, so a .neon, .yml or .json file also triggers it.

In a unified diff, every file line starts with a space, + or -. Only this marker starts with a backslash. Now PatchParser removes such lines before it parses the patch.

• New PatchParserTest with a fixture patch from a real git diff. The test fails on master.

Co-Authored-By: Claude Code