Jeff King wrote:
> On Wed, Sep 20, 2017 at 03:48:26PM -0700, Jonathan Nieder wrote:
>> Jeff King wrote:
>>> Subject: [PATCH] revision: replace "struct cmdline_pathspec" with argv_array
>>>
>>> We assemble an array of strings in a custom struct,
>>> NULL-terminate the result, and then pass it to
>>> parse_pathspec().
>>>
>>> But then we never free the array or the individual strings
>>> (nor can we do the latter, as they are heap-allocated when
>>> they come from stdin but not when they come from the
>>> passed-in argv).
[...]
>> Except... is the idea that this allows the strings from stdin to be
>> freed sooner, as soon as they have been parsed into a "struct
>> pathspec"?
>
> Well, no...the idea is that this is a function which leaks a bunch of
> memory, and we shouldn't have to think hard about how often its leak can
> be triggered or how severe it is. We should just fix it.
I forgot to say: thanks for writing such a pleasant patch.
Reviewed-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
[...]
> I certainly agree that the pathspec interface could use better
> documentation. Patches welcome? :)
Here's such a patch.
-- 8< --
Subject: pathspec doc: parse_pathspec does not maintain references to args
The command line arguments passed to main() are valid for the life of
a program, but the same is not true for all other argv-style arrays
(e.g. when a caller creates an argv_array). Clarify that
parse_pathspec does not rely on the argv passed to it to remain valid.
This makes it easier to tell that callers like "git rev-list --stdin"
are safe and ensures that that is more likely to remain true as the
implementation of parse_pathspec evolves.
Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
---
pathspec.c | 4 ----
pathspec.h | 7 +++++++
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/pathspec.c b/pathspec.c
index e2a23ebc96..cdefdc7cc0 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -526,10 +526,6 @@ static void NORETURN unsupported_magic(const char *pattern,
pattern, sb.buf);
}
-/*
- * Given command line arguments and a prefix, convert the input to
- * pathspec. die() if any magic in magic_mask is used.
- */
void parse_pathspec(struct pathspec *pathspec,
unsigned magic_mask, unsigned flags,
const char *prefix, const char **argv)
diff --git a/pathspec.h b/pathspec.h
index 60e6500401..6420d1080a 100644
--- a/pathspec.h
+++ b/pathspec.h
@@ -70,6 +70,13 @@ struct pathspec {
*/
#define PATHSPEC_LITERAL_PATH (1<<6)
+/*
+ * Given command line arguments and a prefix, convert the input to
+ * pathspec. die() if any magic in magic_mask is used.
+ *
+ * Any arguments used are copied. It is safe for the caller to modify
+ * or free 'prefix' and 'args' after calling this function.
+ */
extern void parse_pathspec(struct pathspec *pathspec,
unsigned magic_mask,
unsigned flags,
--
2.14.1.821.g8fa685d3b7
