Re: git: 590126789c84 - main - diff: Don't compare a file or directory to itself

In message <20260205162739.132689b5@thor.sb211.local>, A FreeBSD User 
writes:
> --Sig_/1e1plY84Qqzw2sr1atKsDpr
> Content-Type: text/plain; charset=UTF-8
> Content-Transfer-Encoding: quoted-printable
>
> Am Tage des Herren Thu, 05 Feb 2026 14:45:49 +0000
> Dag-Erling Sm=C3=B8rgrav <des@FreeBSD.org> schrieb:
>
> > The branch main has been updated by des:
> >=20
> > URL: https://cgit.FreeBSD.org/src/commit/?id=3D590126789c841d80655869bc07=
> 5c8980c173dd1c
> >=20
> > commit 590126789c841d80655869bc075c8980c173dd1c
> > Author:     Dag-Erling Sm=C3=B8rgrav <des@FreeBSD.org>
> > AuthorDate: 2026-02-05 14:39:57 +0000
> > Commit:     Dag-Erling Sm=C3=B8rgrav <des@FreeBSD.org>
> > CommitDate: 2026-02-05 14:39:57 +0000
> >=20
> >     diff: Don't compare a file or directory to itself
> >    =20
> >     While here, stop abusing struct dirent for something we don't even ne=
> ed
> >     to store.
> >    =20
> >     PR:             254455
> >     MFC after:      1 week
> >     Sponsored by:   Klara, Inc.
> >     Reviewed by:    thj, kevans
> >     Differential Revision:  https://reviews.freebsd.org/D55113
> > ---
> >  usr.bin/diff/diffdir.c          | 14 ++++++--------
> >  usr.bin/diff/diffreg.c          |  3 +++
> >  usr.bin/diff/tests/diff_test.sh | 19 +++++++++++++++++++
> >  3 files changed, 28 insertions(+), 8 deletions(-)
> >=20
> > diff --git a/usr.bin/diff/diffdir.c b/usr.bin/diff/diffdir.c
> > index a55a2bec70ee..bd8ef73e785a 100644
> > --- a/usr.bin/diff/diffdir.c
> > +++ b/usr.bin/diff/diffdir.c
> > @@ -41,8 +41,6 @@ static void diffit(struct dirent *, char *, size_t, str=
> uct dirent *,
> >  	char *, size_t, int);
> >  static void print_only(const char *, size_t, const char *);
> > =20
> > -#define d_status	d_type		/* we need to store status for -l */
> > -
> >  struct inode {
> >  	dev_t dev;
> >  	ino_t ino;
> > @@ -258,7 +256,6 @@ diffit(struct dirent *dp, char *path1, size_t plen1, =
> struct dirent *dp2,
> >  			flags |=3D D_EMPTY1;
> >  			memset(&stb1, 0, sizeof(stb1));
> >  		}
> > -
> >  		if (lstat(path2, &stb2) !=3D 0) {
> >  			if (!Nflag || errno !=3D ENOENT) {
> >  				warn("%s", path2);
> > @@ -315,7 +312,6 @@ diffit(struct dirent *dp, char *path1, size_t plen1, =
> struct dirent *dp2,
> >  			flags |=3D D_EMPTY1;
> >  			memset(&stb1, 0, sizeof(stb1));
> >  		}
> > -
> >  		if (stat(path2, &stb2) !=3D 0) {
> >  			if (!Nflag || errno !=3D ENOENT) {
> >  				warn("%s", path2);
> > @@ -328,6 +324,8 @@ diffit(struct dirent *dp, char *path1, size_t plen1, =
> struct dirent *dp2,
> >  		if (stb1.st_mode =3D=3D 0)
> >  			stb1.st_mode =3D stb2.st_mode;
> >  	}
> > +	if (stb1.st_dev =3D=3D stb2.st_dev && stb1.st_ino =3D=3D stb2.st_ino)
> > +		return;
> >  	if (S_ISDIR(stb1.st_mode) && S_ISDIR(stb2.st_mode)) {
> >  		if (rflag)
> >  			diffdir(path1, path2, flags);
> > @@ -337,12 +335,12 @@ diffit(struct dirent *dp, char *path1, size_t plen1=
> , struct dirent
> > *dp2, return;
> >  	}
> >  	if (!S_ISREG(stb1.st_mode) && !S_ISDIR(stb1.st_mode))
> > -		dp->d_status =3D D_SKIPPED1;
> > +		rc =3D D_SKIPPED1;
> >  	else if (!S_ISREG(stb2.st_mode) && !S_ISDIR(stb2.st_mode))
> > -		dp->d_status =3D D_SKIPPED2;
> > +		rc =3D D_SKIPPED2;
> >  	else
> > -		dp->d_status =3D diffreg(path1, path2, flags, 0);
> > -	print_status(dp->d_status, path1, path2, "");
> > +		rc =3D diffreg(path1, path2, flags, 0);
> > +	print_status(rc, path1, path2, "");
> >  }
> > =20
> >  /*
> > diff --git a/usr.bin/diff/diffreg.c b/usr.bin/diff/diffreg.c
> > index 91ae5ee6591a..95c724817ede 100644
> > --- a/usr.bin/diff/diffreg.c
> > +++ b/usr.bin/diff/diffreg.c
> > @@ -372,6 +372,9 @@ diffreg_stone(char *file1, char *file2, int flags, in=
> t capsicum)
> >  		goto closem;
> >  	}
> > =20
> > +	if (stb1.st_dev =3D=3D stb2.st_dev && stb1.st_ino =3D=3D stb2.st_ino)
> > +		goto closem;
> > +
> >  	if (lflag)
> >  		pr =3D start_pr(file1, file2);
> > =20
> > diff --git a/usr.bin/diff/tests/diff_test.sh b/usr.bin/diff/tests/diff_te=
> st.sh
> > index a3f76602cf37..0c8147c7ed18 100755
> > --- a/usr.bin/diff/tests/diff_test.sh
> > +++ b/usr.bin/diff/tests/diff_test.sh
> > @@ -432,6 +432,24 @@ prleak_body()
> >  	atf_check diff -Astone -rul a b
> >  }
> > =20
> > +same_head()
> > +{
> > +	atf_set "descr" "Don't diff a file or directory with itself"
> > +}
> > +same_body()
> > +{
> > +	local n=3D256
> > +	mkdir a
> > +	for hi in $(jot -w%02x $n 0) ; do
> > +		mkdir a/$hi
> > +		for lo in $(jot -w%02x $n 0) ; do
> > +			echo "$hi$lo" >a/$hi/$lo
> > +		done
> > +	done
> > +	ln -s a b
> > +	atf_check timeout 1s diff -rqs a b
> > +}
> > +
> >  atf_init_test_cases()
> >  {
> >  	atf_add_test_case simple
> > @@ -462,4 +480,5 @@ atf_init_test_cases()
> >  	atf_add_test_case bigc
> >  	atf_add_test_case bigu
> >  	atf_add_test_case prleak
> > +	atf_add_test_case same
> >  }
> >=20
> Buildworld seems to fail with newly added diff code:
>
> [...]
> --- all_subdir_usr.bin ---
>   342 |                 rc =3D diffreg(path1, path2, flags, 0);
>       |                 ^
> /usr/src/usr.bin/diff/diffdir.c:343:15: error: use of undeclared identifier=
>  'rc'
>   343 |         print_status(rc, path1, path2, "");

ee44ab936e84 just fixed this.


-- 
Cheers,
Cy Schubert <Cy.Schubert@cschubert.com>
FreeBSD UNIX:  <cy@FreeBSD.org>   Web:  https://FreeBSD.org
NTP:           <cy@nwtime.org>    Web:  https://nwtime.org

			e**(i*pi)+1=0