Re: [PATCH v2] config: reject invalid VAR in 'git -c VAR=VAL command'

Jeff King [off-list ref] writes:

quoted

Backtracking will not fundamentally "fix" parsing of

	a.b=c=.d

between twhse two

	[a "b="] c = ".d"
	[a]      b = "c=.d"

unfortunately, I think.  I do not think it is worth doing the "best
effort" with erroring out when ambiguous, because there is no way
for the end user to disambiguate, unless we introduce a different
syntax, at which point we cannot use config_parse_key() anymore.

Ah, yeah, you're right. I thought the problem was just that the "split"
was too naive, but it really is that the whole syntax is badly
specified.

I guess "git config --list" suffers from the same problem. You can get
around it there with "-z", but that probably would not be very pleasant
here. :)

Probably not worth worrying too much about if nobody is complaining.

Yup.

Anyway, here is an updated one (the part of the patch to t/ is not
shown as it is unchanged).

-- >8 --
Subject: [PATCH] config: use git_config_parse_key() in git_config_parse_parameter()

The parsing of one-shot assignments of configuration variables that
come from the command line historically was quite loose and allowed
anything to pass.  It also downcased everything in the variable name,
even a three-level <section>.<subsection>.<variable> name in which
the <subsection> part must be treated in a case sensitive manner.

Existing git_config_parse_key() helper is used to parse the variable
name that comes from the command line, i.e. "git config VAR VAL",
and handles these details correctly.  Replace the strbuf_tolower()
call in git_config_parse_parameter() with a call to it to correct
both issues.  git_config_parse_key() does a bit more things that are
not necessary for the purpose of this codepath (e.g. it allocates a
separate buffer to return the canonicalized variable name because it
takes a "const char *" input), but we are not in a performance-critical
codepath here.

Signed-off-by: Junio C Hamano <redacted>
---
 config.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/config.c b/config.c
index b8cce1dffa..1c1a1520ff 100644
--- a/config.c
+++ b/config.c

@@ -295,7 +295,9 @@ int git_config_parse_parameter(const char *text,
 			       config_fn_t fn, void *data)
 {
 	const char *value;
+	char *canonical_name;
 	struct strbuf **pair;
+	int ret;
 
 	pair = strbuf_split_str(text, '=', 2);
 	if (!pair[0])

@@ -313,13 +315,15 @@ int git_config_parse_parameter(const char *text,
 		strbuf_list_free(pair);
 		return error("bogus config parameter: %s", text);
 	}
-	strbuf_tolower(pair[0]);
-	if (fn(pair[0]->buf, value, data) < 0) {
-		strbuf_list_free(pair);
-		return -1;
+
+	if (git_config_parse_key(pair[0]->buf, &canonical_name, NULL)) {
+		ret = -1;
+	} else {
+		ret = (fn(canonical_name, value, data) < 0) ? -1 : 0;
+		free(canonical_name);
 	}
 	strbuf_list_free(pair);
-	return 0;
+	return ret;
 }
 
 int git_config_from_parameters(config_fn_t fn, void *data)

-- 
2.12.0-rc2-308-gbf7e63c428