Re: [PATCH 09/19] mingw: accomodate t0060-path-utils for MSYS2

[Johannes Schindelin <Johannes.Schindelin@gmx.de>]

Hi Hannes,

On Sun, 24 Jan 2016, Johannes Sixt wrote:

> Am 24.01.2016 um 16:44 schrieb Johannes Schindelin:
> > On Windows, there are no POSIX paths, only Windows ones (an absolute
> > Windows path looks like "C:\Program Files\Git\ReleaseNotes.html", under
> > most circumstances, forward slashes are also allowed and synonymous to
> > backslashes).
> > 
> > So when a POSIX shell (such as MSYS2's Bash, which is used by Git for
> > Windows to execute all those shell scripts that are part of Git) passes
> > a POSIX path to test-path-utils.exe (which is not POSIX-aware), the path
> > is translated into a Windows path. For example, /etc/profile becomes
> > C:/Program Files/Git/etc/profile.
> > 
> > This path translation poses a problem when passing the root directory as
> > parameter to test-path-utils.exe, as it is not well defined whether the
> > translated root directory should end in a slash or not. MSys1 stripped
> > the trailing slash, but MSYS2 does not.
> > 
> > To work with both behaviors, we simply test what the current system does
> > in the beginning of t0060-path-utils.sh and then adjust the expected
> > longest ancestor length accordingly.
> > 
> > Originally, the Git for Windows project patched MSYS2's runtime to
> > accomodate Git's regression test, but we really should do it the other
> > way round.
> > 
> > Thanks to Ray Donnelly for his patient help with this issue.
> > 
> > Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> > ---
> >   t/t0060-path-utils.sh | 37 ++++++++++++++++++++++---------------
> >   1 file changed, 22 insertions(+), 15 deletions(-)
> > 
> > diff --git a/t/t0060-path-utils.sh b/t/t0060-path-utils.sh
> > index f0152a7..89d03e7 100755
> > --- a/t/t0060-path-utils.sh
> > +++ b/t/t0060-path-utils.sh
> > @@ -7,6 +7,13 @@ test_description='Test various path utilities'
> >   
> >   . ./test-lib.sh
> >   
> > +# On Windows, the root directory "/" is translated into a Windows directory.
> > +# As it is not well-defined whether that Windows directory should end in a
> > +# slash or not, let's test for that and adjust our expected longest ancestor
> > +# length accordingly.
> > +root_offset=0
> > +case "$(test-path-utils print_path /)" in ?*/) root_offset=-1;; esac
> > +
> >   norm_path() {
> >   	expected=$(test-path-utils print_path "$2")
> >   	test_expect_success $3 "normalize path: $1 => $2" \
> 
> In t0060-path-utils.sh, I currently find this:
> 
> # On Windows, we are using MSYS's bash, which mangles the paths.
> # Absolute paths are anchored at the MSYS installation directory,
> # which means that the path / accounts for this many characters:
> rootoff=$(test-path-utils normalize_path_copy / | wc -c)
> # Account for the trailing LF:
> if test $rootoff = 2; then
> 	rootoff=	# we are on Unix
> else
> 	rootoff=$(($rootoff-1))
> fi
> 
> ancestor() {
> 	# We do some math with the expected ancestor length.
> 	expected=$3
> 	if test -n "$rootoff" && test "x$expected" != x-1; then
> 		expected=$(($expected+$rootoff))
> 	fi
> 	test_expect_success "longest ancestor: $1 $2 => $expected" \
> 	"actual=\$(test-path-utils longest_ancestor_length '$1' '$2') &&
> 	 test \"\$actual\" = '$expected'"
> }
> 
> Furthermore, since you are modifying only cases where the expected
> value is not -1 and we already have a check for this case in the
> helper function, wouldn't it be simpler to merge the offset that your
> case needs with the one that we already have?

Good points. I reworked the patch here (will be part of v2):
https://github.com/dscho/git/commit/24767bd

Ciao,
Dscho