diff: document -U without <n> as using default context
The documentation for '-U<n>' implies that the numeric value '<n>' is mandatory. However, the command line parser has historically accepted '-U' without a number. Strictly requiring a number for '-U' would break existing tests (e.g., in 't4013') and likely disrupt user scripts relying on this undocumented behavior. Hence we retain this fallback behavior for backward compatibility, but document it as such. Signed-off-by: Tian Yuchen <cat@malon.dev> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Tian Yuchen committed
Mar 10, 2026 at 17:50 UTC
4f6a803aba9e97650af304b5c266cfbc25b11fcc
2 files changed
+8
-4
Documentation/diff-context-options.adoc
+4
-2
index e161260358..b9ace2aa4b 100644
--- a/Documentation/diff-context-options.adoc
+++ b/Documentation/diff-context-options.adoc
@@ -1,7 +1,9 @@
`-U<n>`::
`--unified=<n>`::
- Generate diffs with _<n>_ lines of context. Defaults to `diff.context`
- or 3 if the config option is unset.
+ Generate diffs with _<n>_ lines of context. The number of context
+ lines defaults to `diff.context` or 3 if the configuration variable
+ is unset. (`-U` without `<n>` is silently accepted as a synonym for
+ `-p` due to a historical accident).
`--inter-hunk-context=<n>`::
Show the context between diff hunks, up to the specified _<number>_
Documentation/diff-options.adoc
+4
-2
index 9cdad6f72a..867bef6312 100644
--- a/Documentation/diff-options.adoc
+++ b/Documentation/diff-options.adoc
@@ -127,8 +127,10 @@ endif::git-log[]
`-U<n>`::
`--unified=<n>`::
- Generate diffs with _<n>_ lines of context instead of
- the usual three.
+ Generate diffs with _<n>_ lines of context. The number of context
+ lines defaults to `diff.context` or 3 if the configuration variable
+ is unset. (`-U` without `<n>` is silently accepted as a synonym for
+ `-p` due to a historical accident).
ifndef::git-format-patch[]
Implies `--patch`.
endif::git-format-patch[]