Thank you for filling out a Git bug report! Please answer the following questions to help us understand your issue. What did you do before the bug happened? (Steps to reproduce your issue) Full reproduction: echo "A\nB\nC" > test1 echo "A\nB\nC\nD\nE\nF" > test2 git diff -U0 test1 test2 What did you expect to happen? (Expected behavior) I expected the header of the change to show the correct "from line index". For reference, a plain git diff: > git diff test1 test2 diff --git a/test1 b/test2 index b1e6722..cead32e 100644 --- a/test1 +++ b/test2 @@ -1,3 +1,6 @@ A B C +D +E +F When passing -U0, I would expect the from line index to be 3 larger, because the 3 lines of context are omitted: diff --git a/test1 b/test2 index b1e6722..cead32e 100644 --- a/test1 +++ b/test2 @@ -4,0 +4,3 @@ C +D +E +F What happened instead? (Actual behavior) The actual output places the new text at line 3: > git diff -U0 test1 test2 diff --git a/test1 b/test2 index b1e6722..cead32e 100644 --- a/test1 +++ b/test2 @@ -3,0 +4,3 @@ C +D +E +F What's different between what you expected and what actually happened? The header information "-3" is incorrect, because if a script wishes to insert the added code using the line indicator, it will place the newly added code at line 3 (before the C). Instead, I would expect "-4", because we wish to insert the DEF starting at line 4. Anything else you want to add: Notably, the bug does not occur when also deleting lines. Now, we are correctly placed at the beginning of line 3: echo "A\nB\nD\nE\nF" > test3 > git diff -U0 test1 test3 diff --git a/test1 b/test3 index b1e6722..98422e9 100644 --- a/test1 +++ b/test3 @@ -3 +3,3 @@ B -C +D +E +F [System Info] git version: git version 2.39.2 (Apple Git-143) cpu: x86_64 no commit associated with this build sizeof-long: 8 sizeof-size_t: 8 shell-path: /bin/sh feature: fsmonitor--daemon uname: Darwin 22.4.0 Darwin Kernel Version 22.4.0: Mon Mar 6 21:00:17 PST 2023; root:xnu-8796.101.5~3/RELEASE_X86_64 x86_64 compiler info: clang: 14.0.3 (clang-1403.0.22.14.1) libc info: no libc information available $SHELL (typically, interactive shell): /bin/zsh [Enabled Hooks]
