mingw: only test index entries for backslashes, not tree entries

During a clone of a repository that contained a file with a backslash in
its name in the past, as of v2.24.1(2), Git for Windows prints errors
like this:

	error: filename in tree entry contains backslash: '\'

The idea is to prevent Git from even trying to write files with
backslashes in their file names: while these characters are valid in
file names on other platforms, on Windows it is interpreted as directory
separator (which would obviously lead to ambiguities, e.g. when there is
a file `a\b` and there is also a file `a/b`).

Arguably, this is the wrong layer for that error: As long as the user
never checks out the files whose names contain backslashes, there should
not be any problem in the first place.

So let's loosen the requirements: we now leave tree entries with
backslashes in their file names alone, but we do require any entries
that are added to the Git index to contain no backslashes on Windows.

Note: just as before, the check is guarded by `core.protectNTFS` (to
allow overriding the check by toggling that config setting), and it
is _only_ performed on Windows, as the backslash is not a directory
separator elsewhere, even when writing to NTFS-formatted volumes.

An alternative approach would be to try to prevent creating files with
backslashes in their file names. However, that comes with its own set of
problems. For example, `git config -f C:\ProgramData\Git\config ...` is
a very valid way to specify a custom config location, and we obviously
do _not_ want to prevent that. Therefore, the approach chosen in this
patch would appear to be better.

This addresses https://github.com/git-for-windows/git/issues/2435

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/read-cache.c b/read-cache.c
index fc80d7982b81bf06d1fc029e443ffc30a3aef9bf..5baf652a5476946b1c56dc59d262d51b6dd8fa59 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -1278,6 +1278,11 @@ static int add_index_entry_with_check(struct index_state *istate, struct cache_e
        int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK;
        int new_only = option & ADD_CACHE_NEW_ONLY;
 
+#ifdef GIT_WINDOWS_NATIVE
+       if (protect_ntfs && strchr(ce->name, '\\'))
+               return error(_("filename in tree entry contains backslash: '%s'"), ce->name);
+#endif
+
        if (!(option & ADD_CACHE_KEEP_CACHE_TREE))
                cache_tree_invalidate_path(istate, ce->name);
 

diff --git a/t/t7415-submodule-names.sh b/t/t7415-submodule-names.sh
index 905a557585afdbf2c0774e804067129058a7ef82..7ae0dc8ff47ee763089284784e6acdbbdbdb4625 100755 (executable)
--- a/t/t7415-submodule-names.sh
+++ b/t/t7415-submodule-names.sh
@@ -207,6 +207,9 @@ test_expect_success MINGW 'prevent git~1 squatting on Windows' '
                        git hash-object -w --stdin)" &&
                rev="$(git rev-parse --verify HEAD)" &&
                hash="$(echo x | git hash-object -w --stdin)" &&
+               test_must_fail git update-index --add \
+                       --cacheinfo 160000,$rev,d\\a 2>err &&
+               test_i18ngrep backslash err &&
                git -c core.protectNTFS=false update-index --add \
                        --cacheinfo 100644,$modules,.gitmodules \
                        --cacheinfo 160000,$rev,c \
@@ -214,9 +217,7 @@ test_expect_success MINGW 'prevent git~1 squatting on Windows' '
                        --cacheinfo 100644,$hash,d./a/x \
                        --cacheinfo 100644,$hash,d./a/..git &&
                test_tick &&
-               git -c core.protectNTFS=false commit -m "module" &&
-               test_must_fail git show HEAD: 2>err &&
-               test_i18ngrep backslash err
+               git -c core.protectNTFS=false commit -m "module"
        ) &&
        test_must_fail git -c core.protectNTFS=false \
                clone --recurse-submodules squatting squatting-clone 2>err &&

diff --git a/tree-walk.c b/tree-walk.c
index 31cec2a08dc6a4490de525c7f31819a98a38e186..bea819d826fb1c855a7b92dbe2605885c12f5c16 100644 (file)
--- a/tree-walk.c
+++ b/tree-walk.c
@@ -43,12 +43,6 @@ static int decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned l
                strbuf_addstr(err, _("empty filename in tree entry"));
                return -1;
        }
-#ifdef GIT_WINDOWS_NATIVE
-       if (protect_ntfs && strchr(path, '\\')) {
-               strbuf_addf(err, _("filename in tree entry contains backslash: '%s'"), path);
-               return -1;
-       }
-#endif
        len = strlen(path) + 1;
 
        /* Initialize the descriptor entry */