[PATCH 1/2] builtin/symbolic-ref.c: add option to fall back to normal ref

["Jan Krüger" <jk@jk.gs>]

Frequently, people want to determine the current value of HEAD in
scripts. However, there is no tool that can always output it, since "git
symbolic-ref" will fail if HEAD isn't currently a symref, and other
tools (e.g. "git rev-parse --symbolic-full-name") will also fail in
one of HEAD's possible modes.

To resolve this situation, add the new -f option to symbolic-ref that
falls back to outputting the value of HEAD as a normal ref if necessary.

Signed-off-by: Jan Krüger <jk@jk.gs>
---
 Documentation/git-symbolic-ref.txt |    7 ++++++-
 builtin/symbolic-ref.c             |   16 ++++++++++++++--
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-symbolic-ref.txt b/Documentation/git-symbolic-ref.txt
index a45d4c4..a05819b 100644
--- a/Documentation/git-symbolic-ref.txt
+++ b/Documentation/git-symbolic-ref.txt
@@ -8,7 +8,7 @@ git-symbolic-ref - Read and modify symbolic refs
 SYNOPSIS
 --------
 [verse]
-'git symbolic-ref' [-q] [-m <reason>] <name> [<ref>]
+'git symbolic-ref' [-q] [-f] [-m <reason>] <name> [<ref>]
 
 DESCRIPTION
 -----------
@@ -33,6 +33,11 @@ OPTIONS
 	symbolic ref but a detached HEAD; instead exit with
 	non-zero status silently.
 
+-f::
+	When showing the current value of <name>, do not fail if it is
+	not a symbolic ref; instead output the SHA1 value referenced by
+	<name>.
+
 -m::
 	Update the reflog for <name> with <reason>.  This is valid only
 	when creating or updating a symbolic ref.
diff --git a/builtin/symbolic-ref.c b/builtin/symbolic-ref.c
index 2ef5962..2e0a86f 100644
--- a/builtin/symbolic-ref.c
+++ b/builtin/symbolic-ref.c
@@ -8,6 +8,8 @@ static const char * const git_symbolic_ref_usage[] = {
 	NULL
 };
 
+static int fallback_regular_ref;
+
 static void check_symref(const char *HEAD, int quiet)
 {
 	unsigned char sha1[20];
@@ -17,10 +19,18 @@ static void check_symref(const char *HEAD, int quiet)
 	if (!refs_heads_master)
 		die("No such ref: %s", HEAD);
 	else if (!(flag & REF_ISSYMREF)) {
-		if (!quiet)
+		if (fallback_regular_ref) {
+			char sha1[20];
+			if (!get_sha1(HEAD, sha1))
+				puts(sha1_to_hex(sha1));
+			else
+				die("failed to resolve ref %s", HEAD);
+			return;
+		} else if (!quiet) {
 			die("ref %s is not a symbolic ref", HEAD);
-		else
+		} else {
 			exit(1);
+		}
 	}
 	puts(refs_heads_master);
 }
@@ -32,6 +42,8 @@ int cmd_symbolic_ref(int argc, const char **argv, const char *prefix)
 	struct option options[] = {
 		OPT__QUIET(&quiet,
 			"suppress error message for non-symbolic (detached) refs"),
+		OPT_BOOLEAN('f', NULL, &fallback_regular_ref,
+					"fall back to showing as a regular ref"),
 		OPT_STRING('m', NULL, &msg, "reason", "reason of the update"),
 		OPT_END(),
 	};
-- 
1.7.9.2.302.g3724c.dirty


From 1fffb746a65aac88d3af9bae785b1cfa58cbf31c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20Kr=C3=BCger?= <jk@jk.gs>
Date: Mon, 27 Feb 2012 22:40:13 +0100
Subject: [PATCH 2/2] builtin/symbolic-ref.c: add option to output shortened
 ref
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

In scripts meant to generate user-consumable output, it can be helpful
to resolve a symbolic ref and output the result in a shortened form,
such as for use in shell prompts. Add a new -s option to allow this.

Signed-off-by: Jan Krüger <jk@jk.gs>
---
 Documentation/git-symbolic-ref.txt |    6 +++++-
 builtin/symbolic-ref.c             |    5 +++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/Documentation/git-symbolic-ref.txt b/Documentation/git-symbolic-ref.txt
index a05819b..7f108ce 100644
--- a/Documentation/git-symbolic-ref.txt
+++ b/Documentation/git-symbolic-ref.txt
@@ -8,7 +8,7 @@ git-symbolic-ref - Read and modify symbolic refs
 SYNOPSIS
 --------
 [verse]
-'git symbolic-ref' [-q] [-f] [-m <reason>] <name> [<ref>]
+'git symbolic-ref' [-q] [-f] [-s] [-m <reason>] <name> [<ref>]
 
 DESCRIPTION
 -----------
@@ -38,6 +38,10 @@ OPTIONS
 	not a symbolic ref; instead output the SHA1 value referenced by
 	<name>.
 
+-s::
+	When showing the value of <name> as a symbolic ref, try to shorten the
+	value, e.g. from `refs/heads/master` to `master`.
+
 -m::
 	Update the reflog for <name> with <reason>.  This is valid only
 	when creating or updating a symbolic ref.
diff --git a/builtin/symbolic-ref.c b/builtin/symbolic-ref.c
index 2e0a86f..df8da11 100644
--- a/builtin/symbolic-ref.c
+++ b/builtin/symbolic-ref.c
@@ -9,6 +9,7 @@ static const char * const git_symbolic_ref_usage[] = {
 };
 
 static int fallback_regular_ref;
+static int shorten;
 
 static void check_symref(const char *HEAD, int quiet)
 {
@@ -32,6 +33,9 @@ static void check_symref(const char *HEAD, int quiet)
 			exit(1);
 		}
 	}
+	if (shorten)
+		refs_heads_master = shorten_unambiguous_ref(
+			refs_heads_master, 0);
 	puts(refs_heads_master);
 }
 
@@ -44,6 +48,7 @@ int cmd_symbolic_ref(int argc, const char **argv, const char *prefix)
 			"suppress error message for non-symbolic (detached) refs"),
 		OPT_BOOLEAN('f', NULL, &fallback_regular_ref,
 					"fall back to showing as a regular ref"),
+		OPT_BOOLEAN('s', NULL, &shorten, "shorten ref output"),
 		OPT_STRING('m', NULL, &msg, "reason", "reason of the update"),
 		OPT_END(),
 	};
-- 
1.7.9.2.302.g3724c.dirty