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[PATCH 2/2] Teach @{upstream} syntax to strbuf_branchanme()

From
Junio C Hamano <gitster@pobox.com>
Date
Jan 20, 2010, 09:38 UTC
Message-ID
<1263980322-4142-3-git-send-email-gitster@pobox.com>
In-Reply-To
<1263980322-4142-1-git-send-email-gitster@pobox.com>

This teaches @{upstream} syntax to interpret_branch_name(), instead of dwim_ref() machinery.

There are places in git UI that behaves differently when you give a local branch name and when you give an extended SHA-1 expression that evaluates to the commit object name at the tip of the branch. The intent is that the special syntax such as @{-1} can stand in as if the user spelled the name of the branch in such places.

The name of the branch "frotz" to switch to ("git checkout frotz"), and the name of the branch "nitfol" to fork a new branch "frotz" from ("git checkout -b frotz nitfol"), are examples of such places. These places take only the name of the branch (e.g. "frotz"), and they are supposed to act differently to an equivalent refname (e.g. "refs/heads/frotz"), so hooking the @{upstream} and @{-N} syntax to dwim_ref() is insufficient when we want to deal with cases a local branch is forked from another local branch and use "forked@{upstream}" to name the forkee branch.

The "upstream" syntax "forked@{u}" is to specify the ref that "forked" is configured to merge with, and most often the forkee is a remote tracking branch, not a local branch. We cannot simply return a local branch name, but that does not necessarily mean we have to returns the full refname (e.g. refs/remotes/origin/frotz, when returning origin/frotz is enough). This update calls shorten_unambiguous_ref() to do so.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 sha1_name.c                   |  116 ++++++++++++++++++++++++++---------------
 t/t1506-rev-parse-upstream.sh |    6 +-
 2 files changed, 77 insertions(+), 45 deletions(-)
diff --git a/sha1_name.c b/sha1_name.c
index fb4e214..2376c6d 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -239,24 +239,10 @@ static int ambiguous_path(const char *path, int len)
 	return slash;
 }
 
-static inline int tracked_suffix(const char *string, int len)
-{
-	const char *suffix[] = { "@{upstream}", "@{u}" };
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(suffix); i++) {
-		int suffix_len = strlen(suffix[i]);
-		if (len >= suffix_len && !memcmp(string + len - suffix_len,
-					suffix[i], suffix_len))
-			return suffix_len;
-	}
-	return 0;
-}
-
 /*
  * *string and *len will only be substituted, and *string returned (for
- * later free()ing) if the string passed in is of the form @{-<n>} or
- * of the form <branch>@{upstream}.
+ * later free()ing) if the string passed in is a magic short-hand form
+ * to name a branch.
  */
 static char *substitute_branch_name(const char **string, int *len)
 {
@@ -270,21 +256,6 @@ static char *substitute_branch_name(const char **string, int *len)
 		return (char *)*string;
 	}
 
-	ret = tracked_suffix(*string, *len);
-	if (ret) {
-		char *ref = xstrndup(*string, *len - ret);
-		struct branch *tracking = branch_get(*ref ? ref : NULL);
-
-		if (!tracking)
-			die ("No tracking branch found for '%s'", ref);
-		free(ref);
-		if (tracking->merge && tracking->merge[0]->dst) {
-			*string = xstrdup(tracking->merge[0]->dst);
-			*len = strlen(*string);
-			return (char *)*string;
-		}
-	}
-
 	return NULL;
 }
 
@@ -354,6 +325,20 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	return logs_found;
 }
 
+static inline int upstream_mark(const char *string, int len)
+{
+	const char *suffix[] = { "@{upstream}", "@{u}" };
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(suffix); i++) {
+		int suffix_len = strlen(suffix[i]);
+		if (suffix_len <= len
+		    && !memcmp(string, suffix[i], suffix_len))
+			return suffix_len;
+	}
+	return 0;
+}
+
 static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 
 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
@@ -371,7 +356,7 @@ 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 (!tracked_suffix(str + at, len - at)) {
+				if (!upstream_mark(str + at, len - at)) {
 					reflog_len = (len-1) - (at+2);
 					len = at;
 				}
@@ -773,17 +758,10 @@ static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 }
 
 /*
- * This reads "@{-N}" syntax, finds the name of the Nth previous
- * branch we were on, and places the name of the branch in the given
- * buf and returns the number of characters parsed if successful.
- *
- * If the input is not of the accepted format, it returns a negative
- * number to signal an error.
- *
- * If the input was ok but there are not N branch switches in the
- * reflog, it returns 0.
+ * Parse @{-N} syntax, return the number of characters parsed
+ * if successful; otherwise signal an error with negative value.
  */
-int interpret_branch_name(const char *name, struct strbuf *buf)
+static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf)
 {
 	long nth;
 	int i, retval;
@@ -828,6 +806,60 @@ release_return:
 }
 
 /*
+ * This reads short-hand syntax that not only evaluates to a commit
+ * object name, but also can act as if the end user spelled the name
+ * of the branch from the command line.
+ *
+ * - "@{-N}" finds the name of the Nth previous branch we were on, and
+ *   places the name of the branch in the given buf and returns the
+ *   number of characters parsed if successful.
+ *
+ * - "<branch>@{upstream}" finds the name of the other ref that
+ *   <branch> is configured to merge with (missing <branch> defaults
+ *   to the current branch), and places the name of the branch in the
+ *   given buf and returns the number of characters parsed if
+ *   successful.
+ *
+ * If the input is not of the accepted format, it returns a negative
+ * number to signal an error.
+ *
+ * If the input was ok but there are not N branch switches in the
+ * reflog, it returns 0.
+ */
+int interpret_branch_name(const char *name, struct strbuf *buf)
+{
+	char *cp;
+	struct branch *upstream;
+	int namelen = strlen(name);
+	int len = interpret_nth_prior_checkout(name, buf);
+	int tmp_len;
+
+	if (!len)
+		return len; /* syntax Ok, not enough switches */
+	if (0 < len)
+		return len; /* consumed from the front */
+	cp = strchr(name, '@');
+	if (!cp)
+		return -1;
+	tmp_len = upstream_mark(cp, namelen - (cp - name));
+	if (!tmp_len)
+		return -1;
+	len = cp + tmp_len - name;
+	cp = xstrndup(name, cp - name);
+	upstream = branch_get(*cp ? cp : NULL);
+	if (!upstream
+	    || !upstream->merge
+	    || !upstream->merge[0]->dst)
+		return error("No upstream branch found for '%s'", cp);
+	free(cp);
+	cp = shorten_unambiguous_ref(upstream->merge[0]->dst, 0);
+	strbuf_reset(buf);
+	strbuf_addstr(buf, cp);
+	free(cp);
+	return len;
+}
+
+/*
  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
  * notably "xyz^" for "parent of xyz"
  */
diff --git a/t/t1506-rev-parse-upstream.sh b/t/t1506-rev-parse-upstream.sh
index a2c7f92..95c9b09 100755
--- a/t/t1506-rev-parse-upstream.sh
+++ b/t/t1506-rev-parse-upstream.sh
@@ -76,7 +76,7 @@ test_expect_success 'checkout -b new my-side@{u} forks from the same' '
 )
 '
 
-test_expect_failure 'merge my-side@{u} records the correct name' '
+test_expect_success 'merge my-side@{u} records the correct name' '
 (
 	sq="'\''" &&
 	cd clone || exit
@@ -90,7 +90,7 @@ test_expect_failure 'merge my-side@{u} records the correct name' '
 )
 '
 
-test_expect_failure 'branch -d other@{u}' '
+test_expect_success 'branch -d other@{u}' '
 	git checkout -t -b other master &&
 	git branch -d @{u} &&
 	git for-each-ref refs/heads/master >actual &&
@@ -98,7 +98,7 @@ test_expect_failure 'branch -d other@{u}' '
 	test_cmp expect actual
 '
 
-test_expect_failure 'checkout other@{u}' '
+test_expect_success 'checkout other@{u}' '
 	git branch -f master HEAD &&
 	git checkout -t -b another master &&
 	git checkout @{u} &&
-- 
1.6.6.513.g63f4c
Previous: Jeff KingNext: Johannes Schindelin
Message 29 of 30 in “default behaviour for `gitmerge` (no arguments)”
  1. Gareth AdamsJan 11, 2010
  2. Junio C HamanoJan 11, 2010
  3. Jeff KingJan 12, 2010
  4. Junio C HamanoJan 12, 2010
  5. Jeff KingJan 12, 2010
  6. Junio C HamanoJan 13, 2010
  7. Johannes SchindelinJan 13, 2010
  8. Junio C HamanoJan 13, 2010
  9. Johannes SchindelinJan 13, 2010
  10. Junio C HamanoJan 13, 2010
  11. Johannes SchindelinJan 13, 2010
  12. Junio C HamanoJan 13, 2010
  13. 0/2 @{u} updatesJunio C Hamano, Jan 20, 2010
  14. 1/2 t1506: more test for @{upstream} syntaxJunio C Hamano, Jan 20, 2010
  15. Jeff KingJan 26, 2010
  16. Junio C HamanoJan 26, 2010
  17. Jeff KingJan 27, 2010
  18. Junio C HamanoJan 27, 2010
  19. Jeff KingJan 28, 2010
  20. Junio C HamanoJan 26, 2010
  21. Jeff KingJan 27, 2010
  22. Junio C HamanoJan 27, 2010
  23. Jeff KingJan 28, 2010
  24. 1/3 test combinations of @{} syntaxJeff King, Jan 28, 2010
  25. 2/3 fix parsing of @{-1}@{u} combinationJeff King, Jan 28, 2010
  26. 3/3 reject @{-1} not at beginning of object nameJeff King, Jan 28, 2010
  27. Junio C HamanoJan 28, 2010
  28. Jeff KingJan 29, 2010
  29. 2/2 Teach @{upstream} syntax to strbuf_branchanme()Junio C Hamano, Jan 20, 2010
  30. Johannes SchindelinJan 20, 2010

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