[PATCH v3 1/2] reflog: name the strings that mark switches, renames and rebase steps

["Harald Nordgren via GitGitGadget" <gitgitgadget@gmail.com>]

From: Harald Nordgren <haraldnordgren@gmail.com>

The next commit adds a "%gb" placeholder that shows which branch HEAD
was on for each reflog entry. It finds the branch from the messages
that branch switches, branch renames and rebases leave in the reflog.
The commands that write these messages spell out the strings by hand,
and "@{-<n>}" and "git status" each keep their own copy of the switch
prefix to read it back. Reading them in one more place would add yet
another copy that has to stay in sync.

Name the strings once in reflog.h and use the names wherever the
messages are written or read: the "checkout: moving from " prefix
written by "git checkout", the "Branch: renamed " prefix written by
"git branch -m", and the "start", "finish" and "abort" steps, the
"returning to " before the branch a rebase goes back to and the
"checkout " before what it checks out, all written by "git rebase".

No change in behavior.

Signed-off-by: Harald Nordgren <haraldnordgren@gmail.com>
---
 builtin/branch.c   |  3 ++-
 builtin/checkout.c |  3 ++-
 builtin/rebase.c   | 19 ++++++++++---------
 object-name.c      |  3 ++-
 reflog.h           |  8 ++++++++
 sequencer.c        | 13 +++++++------
 wt-status.c        |  3 ++-
 7 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/builtin/branch.c b/builtin/branch.c
index a613148fc7..30062ceb7c 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -13,6 +13,7 @@
 #include "editor.h"
 #include "environment.h"
 #include "refs.h"
+#include "reflog.h"
 #include "commit.h"
 #include "gettext.h"
 #include "object-name.h"
@@ -669,7 +670,7 @@ static void copy_or_rename_branch(const char *oldname, const char *newname, int
 		strbuf_addf(&logmsg, "Branch: copied %s to %s",
 			    oldref.buf, newref.buf);
 	else
-		strbuf_addf(&logmsg, "Branch: renamed %s to %s",
+		strbuf_addf(&logmsg, REFLOG_RENAME_PREFIX "%s to %s",
 			    oldref.buf, newref.buf);
 
 	if (!copy && !(oldref_usage & IS_ORPHAN) &&
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 91e0332ec2..1e06586e67 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -26,6 +26,7 @@
 #include "preload-index.h"
 #include "read-cache.h"
 #include "refs.h"
+#include "reflog.h"
 #include "remote.h"
 #include "repo-settings.h"
 #include "resolve-undo.h"
@@ -1037,7 +1038,7 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
 
 	reflog_msg = getenv("GIT_REFLOG_ACTION");
 	if (!reflog_msg)
-		strbuf_addf(&msg, "checkout: moving from %s to %s",
+		strbuf_addf(&msg, REFLOG_SWITCH_PREFIX "%s to %s",
 			old_desc ? old_desc : "(invalid)", new_branch_info->name);
 	else
 		strbuf_insertstr(&msg, 0, reflog_msg);
diff --git a/builtin/rebase.c b/builtin/rebase.c
index 535db60181..47a7b2fd3c 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -17,6 +17,7 @@
 #include "strvec.h"
 #include "dir.h"
 #include "refs.h"
+#include "reflog.h"
 #include "config.h"
 #include "unpack-trees.h"
 #include "lockfile.h"
@@ -601,11 +602,11 @@ static int move_to_original_branch(struct rebase_options *opts)
 	if (!opts->onto)
 		BUG("move_to_original_branch without onto");
 
-	strbuf_addf(&branch_reflog, "%s (finish): %s onto %s",
-		    opts->reflog_action,
+	strbuf_addf(&branch_reflog, "%s (%s): %s onto %s",
+		    opts->reflog_action, REFLOG_STEP_FINISH,
 		    opts->head_name, oid_to_hex(&opts->onto->object.oid));
-	strbuf_addf(&head_reflog, "%s (finish): returning to %s",
-		    opts->reflog_action, opts->head_name);
+	strbuf_addf(&head_reflog, "%s (%s): " REFLOG_RETURNING_TO "%s",
+		    opts->reflog_action, REFLOG_STEP_FINISH, opts->head_name);
 	ropts.branch = opts->head_name;
 	ropts.flags = RESET_WORKING_TREE_REFS_ONLY |
 		      RESET_WORKING_TREE_UPDATE_HEAD;
@@ -867,7 +868,7 @@ static int checkout_up_to_date(struct rebase_options *options)
 	struct reset_working_tree_options ropts = { 0 };
 	int ret = 0;
 
-	strbuf_addf(&buf, "%s: checkout %s",
+	strbuf_addf(&buf, "%s: " REFLOG_CHECKOUT "%s",
 		    options->reflog_action, options->switch_to);
 	ropts.oid = &options->orig_head->object.oid;
 	ropts.branch = options->head_name;
@@ -1413,8 +1414,8 @@ int cmd_rebase(int argc,
 		if (read_basic_state(&options))
 			exit(1);
 
-		strbuf_addf(&head_msg, "%s (abort): returning to %s",
-			    options.reflog_action,
+		strbuf_addf(&head_msg, "%s (%s): " REFLOG_RETURNING_TO "%s",
+			    options.reflog_action, REFLOG_STEP_ABORT,
 			    options.head_name ? options.head_name
 					      : oid_to_hex(&options.orig_head->object.oid));
 		ropts.oid = &options.orig_head->object.oid;
@@ -1884,8 +1885,8 @@ int cmd_rebase(int argc,
 		printf(_("First, rewinding head to replay your work on top of "
 			 "it...\n"));
 
-	strbuf_addf(&msg, "%s (start): checkout %s",
-		    options.reflog_action, options.onto_name);
+	strbuf_addf(&msg, "%s (%s): " REFLOG_CHECKOUT "%s",
+		    options.reflog_action, REFLOG_STEP_START, options.onto_name);
 	ropts.oid = &options.onto->object.oid;
 	ropts.orig_head = &options.orig_head->object.oid;
 	ropts.flags = RESET_WORKING_TREE_DETACH |
diff --git a/object-name.c b/object-name.c
index 6546685760..5b6ce8e0e0 100644
--- a/object-name.c
+++ b/object-name.c
@@ -13,6 +13,7 @@
 #include "tree.h"
 #include "tree-walk.h"
 #include "refs.h"
+#include "reflog.h"
 #include "remote.h"
 #include "dir.h"
 #include "odb.h"
@@ -1251,7 +1252,7 @@ static int grab_nth_branch_switch(const char *refname UNUSED,
 	const char *match = NULL, *target = NULL;
 	size_t len;
 
-	if (skip_prefix(message, "checkout: moving from ", &match))
+	if (skip_prefix(message, REFLOG_SWITCH_PREFIX, &match))
 		target = strstr(match, " to ");
 
 	if (!match || !target)
diff --git a/reflog.h b/reflog.h
index 3bdd1ca8a5..f5586242bf 100644
--- a/reflog.h
+++ b/reflog.h
@@ -2,6 +2,14 @@
 #define REFLOG_H
 #include "refs.h"
 
+#define REFLOG_SWITCH_PREFIX "checkout: moving from "
+#define REFLOG_RENAME_PREFIX "Branch: renamed "
+#define REFLOG_STEP_START "start"
+#define REFLOG_STEP_FINISH "finish"
+#define REFLOG_STEP_ABORT "abort"
+#define REFLOG_RETURNING_TO "returning to "
+#define REFLOG_CHECKOUT "checkout "
+
 #define REFLOG_EXPIRE_TOTAL   (1 << 0)
 #define REFLOG_EXPIRE_UNREACH (1 << 1)
 
diff --git a/sequencer.c b/sequencer.c
index 2ac78e15b8..b2c6d8072a 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -31,6 +31,7 @@
 #include "merge-ort.h"
 #include "merge-ort-wrappers.h"
 #include "refs.h"
+#include "reflog.h"
 #include "sparse-index.h"
 #include "strvec.h"
 #include "quote.h"
@@ -5011,8 +5012,8 @@ static int checkout_onto(struct repository *r, struct replay_opts *opts,
 			 RESET_WORKING_TREE_UPDATE_HEAD |
 			 RESET_WORKING_TREE_UPDATE_ORIG_HEAD |
 			 RESET_WORKING_TREE_RUN_POST_CHECKOUT_HOOK,
-		.head_msg = reflog_message(opts, "start", "checkout %s",
-					   onto_name),
+		.head_msg = reflog_message(opts, REFLOG_STEP_START,
+					   REFLOG_CHECKOUT "%s", onto_name),
 		.default_reflog_action = sequencer_reflog_action(opts)
 	};
 	if (reset_working_tree(r, &ropts)) {
@@ -5311,16 +5312,16 @@ cleanup_head_ref:
 				res = error(_("could not read 'onto'"));
 				goto cleanup_head_ref;
 			}
-			msg = reflog_message(opts, "finish", "%s onto %s",
-				head_ref.buf, buf.buf);
+			msg = reflog_message(opts, REFLOG_STEP_FINISH,
+				"%s onto %s", head_ref.buf, buf.buf);
 			if (refs_update_ref(get_main_ref_store(the_repository), msg, head_ref.buf, &head, &orig,
 					    REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR)) {
 				res = error(_("could not update %s"),
 					head_ref.buf);
 				goto cleanup_head_ref;
 			}
-			msg = reflog_message(opts, "finish", "returning to %s",
-				head_ref.buf);
+			msg = reflog_message(opts, REFLOG_STEP_FINISH,
+				REFLOG_RETURNING_TO "%s", head_ref.buf);
 			if (refs_update_symref(get_main_ref_store(the_repository), "HEAD", head_ref.buf, msg)) {
 				res = error(_("could not update HEAD to %s"),
 					head_ref.buf);
diff --git a/wt-status.c b/wt-status.c
index 238bb48643..3516432338 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -22,6 +22,7 @@
 #include "strvec.h"
 #include "remote.h"
 #include "refs.h"
+#include "reflog.h"
 #include "submodule.h"
 #include "column.h"
 #include "read-cache.h"
@@ -1790,7 +1791,7 @@ static int grab_1st_switch(const char *refname UNUSED,
 	struct grab_1st_switch_cbdata *cb = cb_data;
 	const char *target = NULL, *end;
 
-	if (!skip_prefix(message, "checkout: moving from ", &message))
+	if (!skip_prefix(message, REFLOG_SWITCH_PREFIX, &message))
 		return 0;
 	target = strstr(message, " to ");
 	if (!target)
-- 
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