Re: [PATCH 2/3] range-diff: handle commit ranges other than A..B
From: Junio C Hamano <hidden>
Date: 2021-01-21 23:43:02
"Johannes Schindelin via GitGitGadget" [off-list ref] writes:
quoted hunk
From: Johannes Schindelin <redacted> In the `SPECIFYING RANGES` section of gitrevisions[7], two ways are described to specify commit ranges that `range-diff` does not yet accept: "<commit>^!" and "<commit>^-<n>". Let's accept them. Signed-off-by: Johannes Schindelin <redacted> --- builtin/range-diff.c | 21 ++++++++++++++++++++- t/t3206-range-diff.sh | 8 ++++++++ 2 files changed, 28 insertions(+), 1 deletion(-)diff --git a/builtin/range-diff.c b/builtin/range-diff.c index 551d3e689cb..6097635c432 100644 --- a/builtin/range-diff.c +++ b/builtin/range-diff.c@@ -13,7 +13,26 @@ NULL static int is_range(const char *range) { - return !!strstr(range, ".."); + size_t i; + char c; + + if (strstr(range, "..")) + return 1; + + i = strlen(range); + c = i ? range[--i] : 0; + if (c == '!') + i--; /* might be ...^! or ...^@ */
I am confused. If it ends with '!', I do not see how it can end
with "^@".
If the input were "!", i gets strlen("!") which is 1, c gets '!'
while predecrementing i down to 0, and we notice c is '!' and
decrement i again to make it (size_t)(-1) which is a fairly large
number.
Then we skip all the else/if cascade, ensure that i is positive, and
happily access range[i], which likely is way out of bounds (but it
probably is almost one turn around the earth out of bounds, it may
access just a single byte before the array).
Am I reading the code right?
IOW, "git range-diff \! A..B" would do something strange, I would
guess.
quoted hunk
+ else if (isdigit(c)) { + /* handle ...^-<n> */ + while (i > 2 && isdigit(range[--i])) + ; /* keep trimming trailing digits */ + if (i < 2 || range[i--] != '-') + return 0; + } else + return 0; + + return i > 0 && range[i] == '^'; } int cmd_range_diff(int argc, const char **argv, const char *prefix)diff --git a/t/t3206-range-diff.sh b/t/t3206-range-diff.sh index 6eb344be031..e217cecac9e 100755 --- a/t/t3206-range-diff.sh +++ b/t/t3206-range-diff.sh@@ -150,6 +150,14 @@ test_expect_success 'simple A B C (unmodified)' ' test_cmp expect actual ' +test_expect_success 'A^! and A^-<n> (unmodified)' ' + git range-diff --no-color topic^! unmodified^-1 >actual && + cat >expect <<-EOF && + 1: $(test_oid t4) = 1: $(test_oid u4) s/12/B/ + EOF + test_cmp expect actual +' + test_expect_success 'trivial reordering' ' git range-diff --no-color master topic reordered >actual && cat >expect <<-EOF &&