Unified Diff - Diff of a Checked-In Patch File
Quilt, Debian and vendor trees check patches into the repository, so editing one produces a diff whose body is itself full of `+++`, `---` and `@@` lines and whose section heading is a `diff --git` line. Any scanner that finds file boundaries by searching for those tokens anywhere in the stream splits this single-file diff into several phantom files.
--- a/debian/patches/0001-guard-balances.patch 2026-03-02 09:14:03.000000000 +0000
+++ b/debian/patches/0001-guard-balances.patch 2026-03-02 10:41:55.000000000 +0000
@@ -15,7 +15,7 @@ diff --git a/internal/ledger/apply.go b/internal/ledger/apply.go
return balance, ErrShortBalance
}
+ if delta == 0 {
-+ return balance, nil
++ return balance, nil // no-op posting
+ }
return balance + delta, nil
}
Specifications
- Seed
- 20260807
- Diff Format
- unified
- Context
- 3
- Files
- 1
- Target
- debian/patches/0001-guard-balances.patch
- Nested
- true
- Line Endings
- LF
- Encoding
- UTF-8
Testing contract
Expected to pass- Scenario
- Split a diff into file sections when the hunk bodies contain diff-like text and the section heading is a diff --git line.
- Expected result
- Exactly one file section is reported — debian/patches/0001-guard-balances.patch — and no section is created for internal/ledger/apply.go.
What is a .diff file?
A .diff file records the difference between two versions of one or more text files. The unified format — the default almost everywhere — names the old and new files on `---` and `+++` lines, then lists hunks introduced by `@@ -old,count +new,count @@` in which context lines are unprefixed and changed lines are prefixed with `-` or `+`. Older context and normal diff formats exist but are rarely produced today.
How to use this file
Use an example .diff file to test diff parsers, syntax highlighters, and merge tooling — verifying hunk-offset arithmetic, correct handling of context lines that begin with a space, and behaviour on files whose changes include trailing-whitespace or line-ending differences.
How to use this file for testing
“Unified Diff - Diff of a Checked-In Patch File” is a deterministic Novus Examples fixture for Error handling, Visual diff / regression, Code parsing. Deliberately corrupt and invalid files, clearly labelled, for testing how your tool fails.
Documented properties for this file: seed 20260807 · UTF-8 · LF. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Diff and patch fixtures name their target paths and the exact edge case they exercise — rename, mode change, binary hunk, CRLF↔LF, or missing trailing newline. Apply or render them against the documented before-state; every author, path, and hash is fictional.
Related files
- diffContext Diff - Classic *** / --- FormatThe same change as the unified twin, emitted in the pre-unified context format: `*** before` and `--- after` blocks separated by a row of asterisks, with `!`, `+` and `-` change markers. Parsers that assume every diff starts with `---`/`+++` misread this one as a unified diff with no hunks.
- diffNormal Diff - ed-Style Change CommandsThe default output of bare `diff`: ed-style commands such as `3a4` with `<` and `>` bodies and no file headers at all. Tooling that identifies diffs by looking for `---`, `+++` or `@@` cannot even tell this is a diff, which is exactly what makes it a useful negative fixture.
- diffUnified Diff - Pasted Into an Email BodyA patch as it actually arrives in a mailing-list message: prose above it, a sign-off and an email signature below it, and a signature separator that looks like the start of a deletion. Extractors must find the diff without swallowing the surrounding text.
- txtCODEOWNERS - Intentionally Invalid, Five Distinct DefectsAn intentionally invalid ownership file carrying five defects that all parse as plausible lines: an owner that is neither a handle nor an email, a team with no organisation, a character class, a negation, and a path with an unescaped space. Each is a separate assertion for a linter, and none of them is a syntax error a naive line splitter would notice.
- diffCombined Diff - diff --cc With Two ParentsWhat `git show` prints for a merge commit: a `diff --cc` header, an index line naming three blobs, `@@@` hunk markers, and two prefix columns instead of one. The `++` line is the giveaway a reviewer is looking for — content that appears in the merge result but in neither parent.
- diffCombined Diff - Octopus Merge With Three ParentsAn octopus merge, so the hunk marker grows to `@@@@` and every line carries three prefix columns. Any parser that hard-codes `@@@` or assumes two columns reads the third column as the first character of the line's content.
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