# filenames with " b" in them create confusing git diff-tree output 4 messages from 2007-06-20 to 2007-06-20. Participants: Paul Mackerras, Junio C Hamano, Linus Torvalds. Thread: https://gitlist.dev/t/8663 ## Paul Mackerras, 2007-06-20 11:15 Subject: filenames with " b" in them create confusing git diff-tree output Message-ID: <18041.3163.329391.298926@cargo.ozlabs.ibm.com> URL: https://gitlist.dev/e/18041.3163.329391.298926%40cargo.ozlabs.ibm.com ``` While trying to improve gitk's handling of filenames with spaces, I realised that the header line in git diff-tree's output can be inherently ambiguous, since it doesn't put quotes around filenames with spaces (although it does for filenames with other special characters in them). For example: paulus@quango:~/gitk/testrepo$ mkdir "test b" paulus@quango:~/gitk/testrepo$ cat >"test b/foo" stuff paulus@quango:~/gitk/testrepo$ git add "test b/foo" paulus@quango:~/gitk/testrepo$ git commit -a Created commit 71a3074: Add a "test b" directory 1 files changed, 1 insertions(+), 0 deletions(-) create mode 100644 test b/foo paulus@quango:~/gitk/testrepo$ git diff-tree -r -p -C HEAD 71a3074e723c3e5eb599e6b3c47e3267a3cac3bc diff --git a/test b/foo b/test b/foo new file mode 100644 index 0000000..f2e4113 --- /dev/null +++ b/test b/foo @@ -0,0 +1 @@ +stuff Note how there appear to be 4 filenames on the "diff --git" line. At present gitk will interpret that as a diff between "test" and "foo b/test b/foo", since it looks for " a/" and " b/" to delimit the filenames. Of course if the file got renamed it could get even more confusing. :) Would there be any ill effects from quoting filenames with spaces, do you think? It seems the simplest fix to me (and I will make gitk handle quoted filenames, which it doesn't at present :). Paul. ``` ## Junio C Hamano, 2007-06-20 19:59 Subject: Re: filenames with " b" in them create confusing git diff-tree output Message-ID: <7v4pl2v1lf.fsf@assigned-by-dhcp.pobox.com> URL: https://gitlist.dev/e/7v4pl2v1lf.fsf%40assigned-by-dhcp.pobox.com In-Reply-To: <18041.3163.329391.298926@cargo.ozlabs.ibm.com> ``` Paul Mackerras writes: > paulus@quango:~/gitk/testrepo$ git diff-tree -r -p -C HEAD > 71a3074e723c3e5eb599e6b3c47e3267a3cac3bc > diff --git a/test b/foo b/test b/foo > new file mode 100644 > index 0000000..f2e4113 > --- /dev/null > +++ b/test b/foo > @@ -0,0 +1 @@ > +stuff > > Note how there appear to be 4 filenames on the "diff --git" line. At > present gitk will interpret that as a diff between "test" and > "foo b/test b/foo", since it looks for " a/" and " b/" to delimit the > filenames. Of course if the file got renamed it could get even more > confusing. :) Your example, "a/test b/foo" vs "b/test b/foo", can be and IS parsed unambiguously by git-apply (you can try "git apply --stat" your example). IOW, the code to correctly handle it already exists ;-) If you are seeing a rename/copy you would get explicit rename lines between "diff --git" header and "index HEXHEX..HEXHEX" line, what we (i.e. git-apply) do is to make sure the information we get on the "diff --git" header and those on rename/copy lines match. The latter is more reliable, of course, as they are in strictly one-line-per-filename format, and in fact we use the information from there instead of "diff --git" line for rename patches. And for non-rename case, you can find all instances of "b/", and see if what follows to the end of line of which instance of b/ does match what is between "diff --git a/" and that "b/". In your example, you have three possible "b/" that indicates the beginning of a name: foo b/test b/foo test b/foo foo The leading part after "diff --git a/" for the above three possibilities are: test test b/foo test b/foo b/test and you can tell the second one gives the match. > Would there be any ill effects from quoting filenames with spaces, do > you think? It is very common (I would not do that personally but I do not have a strong reason to advise against when people want to do so) to have a space in filenames. ``` ## Linus Torvalds, 2007-06-20 20:23 Subject: Re: filenames with " b" in them create confusing git diff-tree output Message-ID: URL: https://gitlist.dev/e/alpine.LFD.0.98.0706201315310.3593%40woody.linux-foundation.org In-Reply-To: <7v4pl2v1lf.fsf@assigned-by-dhcp.pobox.com> ``` On Wed, 20 Jun 2007, Junio C Hamano wrote: > > Your example, "a/test b/foo" vs "b/test b/foo", can be and IS > parsed unambiguously by git-apply (you can try "git apply > --stat" your example). IOW, the code to correctly handle it > already exists ;-) Well, in all fairness, I *did* hate having to write the code to handle all the name handling in git-apply. Escaping whitespace (or at least giving the _option_ to do so) might well be a good way to not have to be as smart as git-apply is. git-apply didn't have that option, since git-apply has as one primary motivation the need to be able to handle patches that come from non-git sources, so git-apply goes to quite some extreme lengths to try to make sense of an inherently rather ambiguous format (that the git diffs then *made* unambiguous, but using pretty subtle rules in order to stay compatible). Some maybe we should have some generic method of asking for any filename to be quoted in particular ways? Linus ``` ## Junio C Hamano, 2007-06-20 20:50 Subject: Re: filenames with " b" in them create confusing git diff-tree output Message-ID: <7v3b0mtkor.fsf@assigned-by-dhcp.pobox.com> URL: https://gitlist.dev/e/7v3b0mtkor.fsf%40assigned-by-dhcp.pobox.com In-Reply-To: ``` Linus Torvalds writes: > Some maybe we should have some generic method of asking for any filename > to be quoted in particular ways? Probably, especially if you notice there has been a separate thread whose title begins with a word "Stupid". ```