[PATCH v3 1/3] parse_insn_line(): improve error message when parsing failed

From: Johannes Schindelin via GitGitGadget <gitgitgadget@gmail.com>
Date: Jan 23, 2020, 12:28 UTC
Message-ID: <6f5c7b032524ed2510286caa0623fdbfa2b02eb3.1579782500.git.gitgitgadget@gmail.com>
In-Reply-To: <pull.529.v3.git.1579782499.gitgitgadget@gmail.com>

From: Johannes Schindelin <johannes.schindelin@gmx.de>

In the case that a `get_oid()` call failed, we showed some rather bogus part of the line instead of the precise string we sent to said function. That makes it rather hard for users to understand what is going wrong, so let's fix that.

While at it, return a negative value from `parse_insn_line()` in case of an error, as per our convention. This function's only caller, `todo_list_parse_insn_buffer()`, cares only whether that return value is non-zero or not, i.e. does not need to be changed.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 sequencer.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/sequencer.c b/sequencer.c
index b9dbf1adb0..7c30dad59c 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -2118,6 +2118,8 @@ static int parse_insn_line(struct repository *r, struct todo_item *item,
 	saved = *end_of_object_name;
 	*end_of_object_name = '\0';
 	status = get_oid(bol, &commit_oid);
+	if (status < 0)
+		error(_("could not parse '%s'"), bol); /* return later */
 	*end_of_object_name = saved;
 
 	bol = end_of_object_name + strspn(end_of_object_name, " \t");
@@ -2125,11 +2127,10 @@ static int parse_insn_line(struct repository *r, struct todo_item *item,
 	item->arg_len = (int)(eol - bol);
 
 	if (status < 0)
-		return error(_("could not parse '%.*s'"),
-			     (int)(end_of_object_name - bol), bol);
+		return status;
 
 	item->commit = lookup_commit_reference(r, &commit_oid);
-	return !item->commit;
+	return item->commit ? 0 : -1;
 }
 
 int sequencer_get_last_command(struct repository *r, enum replay_action *action)

-- 
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