Subject: Re: [PATCH 5/7] t0060: test obscured .gitattributes and .gitignore matching

From: Jonathan Nieder <[email-masked]>
Date: Mon, 5 Oct 2020 01:03:53 -0700

(+cc: Dscho for NTFS savvy)
Jeff King wrote:

> We have tests that cover various filesystem-specific spellings of
> ".gitmodules", because we need to reliably identify that path for some
> security checks. These are from dc2d9ba318 (is_{hfs,ntfs}_dotgitmodules:
> add tests, 2018-05-12), with the actual code coming from e7cb0b4455
> (is_ntfs_dotgit: match other .git files, 2018-05-11) and 0fc333ba20
> (is_hfs_dotgit: match other .git files, 2018-05-02).
>
> Those latter two commits also added similar matching functions for
> .gitattributes and .gitignore. These ended up not being used in the
> final series, and are currently dead code. But in preparation for them
> being used, let's make sure they actually work by throwing a few basic
> checks at them.
>
> I didn't bother with the whole battery of tests that we cover for
> .gitmodules. These functions are all based on the same generic matcher,
> so it's sufficient to test most of the corner cases just once.

Yeah, that's reasonable.

> Note that the ntfs magic prefix names in the tests come from the
> algorithm described in e7cb0b4455 (and are different for each file).

Doesn't block this patch, but I'm curious: how hard would it be to make
a test with an NTFS prerequisite that makes sure we got the magic prefix
right?

> Signed-off-by: Jeff King <[email-masked]>
> ---
>  t/helper/test-path-utils.c | 41 ++++++++++++++++++++++++++------------
>  t/t0060-path-utils.sh      | 20 +++++++++++++++++++
>  2 files changed, 48 insertions(+), 13 deletions(-)
> 
> diff --git a/t/helper/test-path-utils.c b/t/helper/test-path-utils.c
> index 313a153209..9e253f8058 100644
> --- a/t/helper/test-path-utils.c
> +++ b/t/helper/test-path-utils.c
> @@ -172,9 +172,22 @@ static struct test_data dirname_data[] = {
>  	{ NULL,              NULL     }
>  };
>  
> -static int is_dotgitmodules(const char *path)
> +static int check_dotgitx(const char *x, const char **argv,
> +			 int (*is_hfs)(const char *),
> +			 int (*is_ntfs)(const char *))
>  {
> -	return is_hfs_dotgitmodules(path) || is_ntfs_dotgitmodules(path);
> +	int res = 0, expect = 1;
> +	for (; *argv; argv++) {
> +		if (!strcmp("--not", *argv))
> +			expect = !expect;
> +		else if (expect != (is_hfs(*argv) || is_ntfs(*argv)))
> +			 res = error("'%s' is %s.%s", *argv,
> +				     expect ? "not " : "", x);
> +		else
> +			fprintf(stderr, "ok: '%s' is %s.%s\n",
> +				*argv, expect ? "" : "not ", x);

micronit: extra space on the "res" line.

This "if" cascade is a little hard to read, even though it does the
right thing.  Can we make it more explicit?  E.g.

		if (!strcmp("--not", *argv)) {
			expect = !expect;
			continue;
		}

		actual = is_hfs(*argv) || is_ntfs(*argv);

		fprintf(stderr, "%s: '%s' is %s%s",
			expect == actual ? "ok" : "error",
			*argv, actual ? "" : "not ", x);
		if (expect != actual)
			res = -1;

I think it's a little easier to read with either (a) the dot included
in the 'x' parameter or (b) the entire ".git" missing from the 'x'
parameter.

[...]
> index 56db5c8aba..b2e3cf3f4c 100755
> --- a/t/t0060-path-utils.sh
> +++ b/t/t0060-path-utils.sh
> @@ -468,6 +468,26 @@ test_expect_success 'match .gitmodules' '
>  		.gitmodules,:\$DATA
>  '
>  
> +test_expect_success 'match .gitattributes' '
> +	test-tool path-utils is_dotgitattributes \
> +		.gitattributes \
> +		.git${u200c}attributes \
> +		.Gitattributes \
> +		.gitattributeS \
> +		GITATT~1 \
> +		GI7D29~1
> +'
> +
> +test_expect_success 'match .gitignore' '
> +	test-tool path-utils is_dotgitignore \
> +		.gitignore \
> +		.git${u200c}ignore \
> +		.Gitignore \
> +		.gitignorE \
> +		GITIGN~1 \
> +		GI250A~1
> +'
> +
>  test_expect_success MINGW 'is_valid_path() on Windows' '
>  	test-tool path-utils is_valid_path \
>  		win32 \

With whatever subset of the changes above makes sense,
Reviewed-by: Jonathan Nieder <[email-masked]>

Thanks.