word-diff-regex=. sometimes ignores newlines

From: 高橋全 (Tamo) <ttakah@gmail.com>
Date: Sep 3, 2024, 12:30 UTC
Message-ID: <CABiJAjbEpYkcrxj82uQ=O27tR9fKoUFH0=MOCobDfa9cWsbdAA@mail.gmail.com>

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)

mkdir test cd test git init

cat >a.txt <<EOF NRZ /NZRQ/NBRQ/ NRZ(C) /NZRCQ/ NRZ(M) /NZRMQ/ EOF

git add a.txt git commit -m 1

cat >a.txt <<EOF NRZ /NZRMQ/NZRCQ/NZRQ/NBRQ/ EOF

git diff --word-diff-regex=.

What did you expect to happen? (Expected behavior)

diff --git a/a.txt b/a.txt
index 278ea76..7e6f42f 100644
--- a/a.txt
+++ b/a.txt
@@ -1,3 +1 @@
NRZ /NZR{+M+}Q/N[-BRQ/-]{+ZRCQ/NZRQ/NBRQ/+}
[-NRZ(C) /NZRCQ/-]
[-NRZ(M) /NZRMQ/-]

or anything whose hunk has three lines


What happened instead? (Actual behavior)

diff --git a/a.txt b/a.txt
index 278ea76..7e6f42f 100644
--- a/a.txt
+++ b/a.txt
@@ -1,3 +1 @@
NRZ /NZR{+M+}Q/N[-BRQ/-]
[-NRZ(C) /N-]ZRCQ/N[-R-]Z[-(M) -]{+RQ+}/N[-Z-]{+B+}R[-M-]Q/



What's different between what you expected and what actually happened?

some newlines are ignored
and the length of the hunk is wrong;
git says "@@ -1,3 +1 @@" but the hunk has only 2 lines



Anything else you want to add:

this may be clearer with --word-diff=porcelain
because it doesn't emit enough number of "~"s


```
$ git diff --word-diff-regex=. --word-diff=porcelain
diff --git a/a.txt b/a.txt
index 278ea76..7e6f42f 100644
--- a/a.txt
+++ b/a.txt
@@ -1,3 +1 @@
 NRZ /NZR
+M
 Q/N
-BRQ/
~
-NRZ(C) /N
 ZRCQ/N
-R
 Z
-(M)
+RQ
 /N
-Z
+B
 R
-M
 Q/
~
```

this should emit 3 tildes




Please review the rest of the bug report below.
You can delete any lines you don't wish to share.


[System Info]
git version:
git version 2.46.0
cpu: x86_64
no commit associated with this build
sizeof-long: 8
sizeof-size_t: 8
shell-path: /bin/sh
libcurl: 7.68.0
zlib: 1.2.11
uname: Linux 5.15.153.1-microsoft-standard-WSL2 #1 SMP Fri Mar 29
23:14:13 UTC 2024 x86_64
compiler info: gnuc: 9.4
libc info: glibc: 2.31
$SHELL (typically, interactive shell): /bin/bash


[Enabled Hooks]