Re: default behaviour for `gitmerge` (no arguments)

From

Junio C Hamano <gitster@pobox.com>

Date

Jan 13, 2010, 06:57 UTC

Message-ID

<7vwrzmqypn.fsf@alter.siamese.dyndns.org>

In-Reply-To

<20100112182550.GA15696@coredump.intra.peff.net>

Jeff King <peff@peff.net> writes:

> Ah, right. I remembered hating "%" even as I typed it, but I had
> forgotten about the followup discussion. Looking at it again, I note:
>
>   1. The last posted patch still has a misplaced free() (patch below),
>      but I think otherwise is not buggy.
>
>   2. We don't complain on "git show @{usptream}" and we probably should.
>      I remember there being some complications because the contents of
>      @{} were passed to approxidate, but I think we can get around that
>      by letting approxidate complain if _nothing_ in the date was
>      useful. So "git show @{2.weeks.and.7.hot.dogs.ago}" would still
>      work, but "git show @{totally.bogus.input}" would complain.
>
>   3. I have actually been running with Dscho's patch for the last couple
>      of months, and I don't remember using it once. So perhaps it is not
>      as useful as I might have thought. :)

I presume we are discussing this patch?

    http://article.gmane.org/gmane.comp.version-control.git/128121

I'll squash the free() fix; thanks.

I agree with your point #2 above.

        git fetch &&
        for local in my set of local branches
        do
                git checkout $local &&
                git merge $local@{upstream} || {
                        echo failed to merge on $local
                        break
                }
        done

In this set-up, for example:

    [remote "filfre"]
        url = ...
        fetch = +refs/heads/nitfol:refs/heads/rezrov
    [branch "frotz"]
        remote = filfre
        merge = refs/heads/nitfol

 - The purpose of rezrov is to keep a tab on the progress of the nitfol
   branch at the remote end.  We say rezrov is a remote tracking branch
   for nitfol from filfre.

 - On the other hand, we have branch frotz that forked from nitfol that
   came from filfre.  It builds on top of that history by occasionally
   merging with it at key points in the history.  So we say frotz builds
   on top of nitfol from filfre.  We also say nitfol at filfre is the
   upstream of frotz.

-- >8 --
Date: Thu, 10 Sep 2009 17:25:57 +0200
Subject: [PATCH] Introduce <branch>@{upstream} notation

This allows you to run, for example,

	for l in list of local branches
	do
		git log --oneline --left-right $l...$l@{upstream}
	done

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/git-rev-parse.txt |    4 ++
 sha1_name.c                     |   39 ++++++++++++++++++++--
 t/t1506-rev-parse-upstream.sh   |   69 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 109 insertions(+), 3 deletions(-)
 create mode 100755 t/t1506-rev-parse-upstream.sh

diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index 82045a2..923b56a 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -231,6 +231,10 @@ when you run 'git-merge'.
 * The special construct '@\{-<n>\}' means the <n>th branch checked out
   before the current one.
 
+* The suffix '@{upstream}' to a ref (short form 'ref@{u}') refers to
+  the branch the ref is set to build on top of.  Missing ref defaults
+  to the current branch.
+
 * A suffix '{caret}' to a revision parameter means the first parent of
   that commit object.  '{caret}<n>' means the <n>th parent (i.e.
   'rev{caret}'
diff --git a/sha1_name.c b/sha1_name.c
index 44bb62d..fb4e214 100644
--- a/sha1_name.c
+++ b/sha1_name.c
@@ -5,6 +5,7 @@
 #include "blob.h"
 #include "tree-walk.h"
 #include "refs.h"
+#include "remote.h"
 
 static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
 {
@@ -238,9 +239,24 @@ 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>}.
+ * later free()ing) if the string passed in is of the form @{-<n>} or
+ * of the form <branch>@{upstream}.
  */
 static char *substitute_branch_name(const char **string, int *len)
 {
@@ -254,6 +270,21 @@ 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;
 }
 
@@ -340,8 +371,10 @@ 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] == '{') {
-				reflog_len = (len-1) - (at+2);
-				len = at;
+				if (!tracked_suffix(str + at, len - at)) {
+					reflog_len = (len-1) - (at+2);
+					len = at;
+				}
 				break;
 			}
 		}
diff --git a/t/t1506-rev-parse-upstream.sh b/t/t1506-rev-parse-upstream.sh
new file mode 100755
index 0000000..5abdc13
--- /dev/null
+++ b/t/t1506-rev-parse-upstream.sh
@@ -0,0 +1,69 @@
+#!/bin/sh
+
+test_description='test <branch>@{upstream} syntax'
+
+. ./test-lib.sh
+
+
+test_expect_success 'setup' '
+
+	test_commit 1 &&
+	git checkout -b side &&
+	test_commit 2 &&
+	git checkout master &&
+	git clone . clone &&
+	test_commit 3 &&
+	(cd clone &&
+	 test_commit 4 &&
+	 git branch --track my-side origin/side)
+
+'
+
+full_name () {
+	(cd clone &&
+	 git rev-parse --symbolic-full-name "$@")
+}
+
+commit_subject () {
+	(cd clone &&
+	 git show -s --pretty=format:%s "$@")
+}
+
+test_expect_success '@{upstream} resolves to correct full name' '
+	test refs/remotes/origin/master = "$(full_name @{upstream})"
+'
+
+test_expect_success '@{u} resolves to correct full name' '
+	test refs/remotes/origin/master = "$(full_name @{u})"
+'
+
+test_expect_success 'my-side@{upstream} resolves to correct full name' '
+	test refs/remotes/origin/side = "$(full_name my-side@{u})"
+'
+
+test_expect_success 'my-side@{u} resolves to correct commit' '
+	git checkout side &&
+	test_commit 5 &&
+	(cd clone && git fetch) &&
+	test 2 = "$(commit_subject my-side)" &&
+	test 5 = "$(commit_subject my-side@{u})"
+'
+
+test_expect_success 'not-tracking@{u} fails' '
+	test_must_fail full_name non-tracking@{u} &&
+	(cd clone && git checkout --no-track -b non-tracking) &&
+	test_must_fail full_name non-tracking@{u}
+'
+
+test_expect_success '<branch>@{u}@{1} resolves correctly' '
+	test_commit 6 &&
+	(cd clone && git fetch) &&
+	test 5 = $(commit_subject my-side@{u}@{1})
+'
+
+test_expect_success '@{u} without specifying branch fails on a detached HEAD' '
+	git checkout HEAD^0 &&
+	test_must_fail git rev-parse @{u}
+'
+
+test_done

-- 
1.6.6.280.ge295b7.dirty