Re: [PATCH v2] sha1_name: reorganize get_sha1_basic()
From: Ramkumar Ramachandra <hidden>
Date: 2016-06-15 22:57:07
Felipe Contreras wrote:
[...]
Okay, you used nth_prior in this one.
There is no need to call this function recursively with the branch of
@{-N} substituted because dwim_{ref,log} already replaces it.
I figured that the recursion is because dwim_{ref,log} didn't exist
when this was written.
However, there's one corner-case where @{-N} resolves to a detached
HEAD, in which case we wouldn't get any ref back.
So we parse the nth-prior manually, and deal with it depending on
weather it's a SHA-1, or a ref.Right. _This_ is the special case, which the old logic didn't quite convey. The end-user version of this is: 'git checkout -' won't bring you back to the branch if you said git checkout HEAD~1 earlier.
quoted hunk ↗ jump to hunk
diff --git a/sha1_name.c b/sha1_name.c index 3820f28..6428001 100644 --- a/sha1_name.c +++ b/sha1_name.c@@ -431,13 +431,14 @@ static inline int upstream_mark(const char *string, int len) } static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags); +static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf);
It didn't strike me to use interpret_nth_prior_checkout() directly. I was still stuck at interpret_branch_name() returning a positive value.
quoted hunk ↗ jump to hunk
static int get_sha1_basic(const char *str, int len, unsigned char *sha1) { static const char *warn_msg = "refname '%.*s' is ambiguous."; char *real_ref = NULL; int refs_found = 0; - int at, reflog_len; + int at, reflog_len, nth_prior = 0; if (len == 40 && !get_sha1_hex(str, sha1)) return 0;@@ -447,6 +448,10 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1) if (len && str[len-1] == '}') { for (at = len-2; at >= 0; at--) { if (str[at] == '@' && str[at+1] == '{') { + if (at == 0 && str[2] == '-') { + nth_prior = 1; + continue; + }
Looking at this closely once again.
You've already hit the beginning. What are you continuing? Take the
example of a compound expression with @{-
@{-1}@{0}
^ at is here
"@{-" is not matched
@{-1}@{0}
^ at is here
"@{-" is matched
What's to continue? at is already at 0
On another note, I think you've fixed a bug: @{-1}{0} was parsing to
the same value as @{-1}@{0} before your patch.
quoted hunk ↗ jump to hunk
@@ -460,20 +465,22 @@ static int get_sha1_basic(const char *str, int len, unsigned char *sha1) if (len && ambiguous_path(str, len)) return -1; - if (!len && reflog_len) { + if (nth_prior) {
nth_prior makes this much cleaner overall.
struct strbuf buf = STRBUF_INIT;
- int ret;
- /* try the @{-N} syntax for n-th checkout */
- ret = interpret_branch_name(str+at, &buf);
- if (ret > 0) {
- /* substitute this branch name and restart */
- return get_sha1_1(buf.buf, buf.len, sha1, 0);
- } else if (ret == 0) {
- return -1;
+ int detached;
+
+ if (interpret_nth_prior_checkout(str, &buf) > 0) {
+ detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
+ strbuf_release(&buf);
+ if (detached)
+ return 0;Neat. I'd set reflog_len to zero and made sure that the last part of the function wouldn't be executed. How did you get away without setting refs_found to 1 though?
}
+ }
+
+ if (!len && reflog_len)
/* allow "@{...}" to mean the current branch reflog */
refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);I got this part wrong too: I said dwim_log() instead of dwim_ref().
- } else if (reflog_len)
+ else if (reflog_len)
refs_found = dwim_log(str, len, sha1, &real_ref);
else
refs_found = dwim_ref(str, len, sha1, &real_ref);
--
1.8.3.rc0.401.g45bba44