Re: [PATCH 2/2] pathspec: allow escaped query values

[Brandon Williams]

On 03/09, Jonathan Tan wrote:
> On 03/09/2017 01:07 PM, Brandon Williams wrote:
> >diff --git a/t/t6135-pathspec-with-attrs.sh b/t/t6135-pathspec-with-attrs.sh
> >index b5e5a0607..585d17bad 100755
> >--- a/t/t6135-pathspec-with-attrs.sh
> >+++ b/t/t6135-pathspec-with-attrs.sh
> >@@ -178,4 +178,13 @@ test_expect_success 'abort on asking for wrong magic' '
> > test_must_fail git ls-files . ":(attr:!label=foo)"
> > '
> >
> >+test_expect_success 'check attribute list' '
> >+cat <<-EOF >>.gitattributes &&
> >+* whitespace=indent,trail,space
> >+EOF
> >+git ls-files ":(attr:whitespace=indent\,trail\,space)" >actual &&
> >+git ls-files >expect &&
> >+test_cmp expect actual
> >+'
> >+
> > test_done
> 
> Is there a way to verify that `\,` is not escaped by the shell into `,`?

You can run with GIT_TRACE=1 to see the actual string passed to git.
'\,' is indeed passed to git with no problems. 

> 
> Maybe also add tests that show \ as the last character and \
> escaping another \.

Done

-- 
Brandon Williams

Re: [PATCH 2/2] pathspec: allow escaped query values

[Jonathan Tan]

On 03/09/2017 01:07 PM, Brandon Williams wrote:

diff --git a/t/t6135-pathspec-with-attrs.sh b/t/t6135-pathspec-with-attrs.sh
index b5e5a0607..585d17bad 100755
--- a/t/t6135-pathspec-with-attrs.sh
+++ b/t/t6135-pathspec-with-attrs.sh
@@ -178,4 +178,13 @@ test_expect_success 'abort on asking for wrong magic' '
test_must_fail git ls-files . ":(attr:!label=foo)"
 '

+test_expect_success 'check attribute list' '
+   cat <<-EOF >>.gitattributes &&
+   * whitespace=indent,trail,space
+   EOF
+   git ls-files ":(attr:whitespace=indent\,trail\,space)" >actual &&
+   git ls-files >expect &&
+   test_cmp expect actual
+'
+
 test_done


Is there a way to verify that `\,` is not escaped by the shell into `,`?

Maybe also add tests that show \ as the last character and \ escaping 
another \.

[PATCH 2/2] pathspec: allow escaped query values

[Brandon Williams]

In our own .gitattributes file we have attributes such as:

*.[ch] whitespace=indent,trail,space

When querying for attributes we want to be able to ask for the exact
value, i.e.

git ls-files :(attr:whitespace=indent,trail,space)

should work, but the commas are used in the attr magic to introduce
the next attr, such that this query currently fails with

fatal: Invalid pathspec magic 'trail' in ':(attr:whitespace=indent,trail,space)'

This change allows escaping characters by a backslash, such that the query

git ls-files :(attr:whitespace=indent\,trail\,space)

will match all path that have the value "indent,trail,space" for the
whitespace attribute. To accomplish this, we need to modify two places.
First `parse_long_magic` needs to not stop early upon seeing a comma or
closing paren that is escaped. As a second step we need to remove any
escaping from the attr value.

Based on a patch by Stefan Beller 
Signed-off-by: Brandon Williams 
---
 pathspec.c | 52 ++
 t/t6135-pathspec-with-attrs.sh |  9 
 2 files changed, 57 insertions(+), 4 deletions(-)

diff --git a/pathspec.c b/pathspec.c
index 583ed5208..f89f84a83 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -89,6 +89,51 @@ static void prefix_magic(struct strbuf *sb, int prefixlen, 
unsigned magic)
strbuf_addf(sb, ",prefix:%d)", prefixlen);
 }
 
+static size_t strcspn_escaped(const char *s, const char *stop)
+{
+   const char *i;
+
+   for (i = s; *i; i++) {
+   /* skip the escaped character */
+   if (i[0] == '\\' && i[1]) {
+   i++;
+   continue;
+   }
+
+   if (strchr(stop, *i))
+   break;
+   }
+   return i - s;
+}
+
+static inline int invalid_value_char(const char ch)
+{
+   if (isalnum(ch) || strchr(",-_", ch))
+   return 0;
+   return -1;
+}
+
+static char *attr_value_unescape(const char *value)
+{
+   const char *src;
+   char *dst, *ret;
+
+   ret = xmallocz(strlen(value));
+   for (src = value, dst = ret; *src; src++, dst++) {
+   if (*src == '\\') {
+   if (!src[1])
+   die(_("Escape character '\\' not allowed as "
+ "last character in attr value"));
+   src++;
+   }
+   if (invalid_value_char(*src))
+   die("cannot use '%c' for value matching", *src);
+   *dst = *src;
+   }
+   *dst = '\0';
+   return ret;
+}
+
 static void parse_pathspec_attr_match(struct pathspec_item *item, const char 
*value)
 {
struct string_list_item *si;
@@ -133,10 +178,9 @@ static void parse_pathspec_attr_match(struct pathspec_item 
*item, const char *va
if (attr[attr_len] != '=')
am->match_mode = MATCH_SET;
else {
+   const char *v = [attr_len + 1];
am->match_mode = MATCH_VALUE;
-   am->value = xstrdup([attr_len + 1]);
-   if (strchr(am->value, '\\'))
-   die(_("attr spec values must not 
contain backslashes"));
+   am->value = attr_value_unescape(v);
}
break;
}
@@ -239,7 +283,7 @@ static const char *parse_long_magic(unsigned *magic, int 
*prefix_len,
const char *nextat;
 
for (pos = elem + 2; *pos && *pos != ')'; pos = nextat) {
-   size_t len = strcspn(pos, ",)");
+   size_t len = strcspn_escaped(pos, ",)");
int i;
 
if (pos[len] == ',')
diff --git a/t/t6135-pathspec-with-attrs.sh b/t/t6135-pathspec-with-attrs.sh
index b5e5a0607..585d17bad 100755
--- a/t/t6135-pathspec-with-attrs.sh
+++ b/t/t6135-pathspec-with-attrs.sh
@@ -178,4 +178,13 @@ test_expect_success 'abort on asking for wrong magic' '
test_must_fail git ls-files . ":(attr:!label=foo)"
 '
 
+test_expect_success 'check attribute list' '
+   cat <<-EOF >>.gitattributes &&
+   * whitespace=indent,trail,space
+   EOF
+   git ls-files ":(attr:whitespace=indent\,trail\,space)" >actual &&
+   git ls-files >expect &&
+   test_cmp expect actual
+'
+
 test_done
-- 
2.12.0.246.ga2ecc84866-goog