[PATCH v2 05/17] index-info.c: return unrecognized lines to caller

["Victoria Dye via GitGitGadget" <gitgitgadget@gmail.com>]

From: Victoria Dye <vdye@github.com>

Update 'read_index_info()' to return INDEX_INFO_UNRECOGNIZED_LINE (value 1),
rather than die()-ing when the function encounters a line that cannot be
parsed according to one of the accepted formats. This grants the caller the
flexibility to fall back on custom handling for such lines rather than a
returning a catch-all error. In the case of 'update-index', we'll still exit
with a "malformed input line" error. However, when 'read_index_info()' is
used to process the input to 'mktree' in a later patch, an empty line return
value will signal a new tree in --batch mode.

Signed-off-by: Victoria Dye <vdye@github.com>
---
 builtin/update-index.c |  9 +++++++--
 index-info.c           | 16 +++++++++-------
 index-info.h           |  5 ++++-
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/builtin/update-index.c b/builtin/update-index.c
index fddf59b54c1..8d0b40a6fd6 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -787,11 +787,16 @@ static enum parse_opt_result stdin_cacheinfo_callback(
 		ret = error("option '%s' must be the last argument", opt->long_name);
 	} else {
 		int *nul_term_line = opt->value;
+		struct strbuf line = STRBUF_INIT;
 
 		allow_add = allow_replace = allow_remove = 1;
-		ret = read_index_info(*nul_term_line, apply_index_info, NULL);
-		if (ret)
+		ret = read_index_info(*nul_term_line, apply_index_info, NULL, &line);
+
+		if (ret == INDEX_INFO_UNRECOGNIZED_LINE)
+			ret = error("malformed input line '%s'", line.buf);
+		else if (ret)
 			ret = -1;
+		strbuf_release(&line);
 	}
 
 	return ret;
diff --git a/index-info.c b/index-info.c
index 8ccaac5487b..7a02f66426a 100644
--- a/index-info.c
+++ b/index-info.c
@@ -5,16 +5,16 @@
 #include "strbuf.h"
 #include "quote.h"
 
-int read_index_info(int nul_term_line, each_index_info_fn fn, void *cbdata)
+int read_index_info(int nul_term_line, each_index_info_fn fn, void *cbdata,
+		    struct strbuf *line)
 {
 	const int hexsz = the_hash_algo->hexsz;
-	struct strbuf buf = STRBUF_INIT;
 	struct strbuf uq = STRBUF_INIT;
 	strbuf_getline_fn getline_fn;
 	int ret = 0;
 
 	getline_fn = nul_term_line ? strbuf_getline_nul : strbuf_getline_lf;
-	while (getline_fn(&buf, stdin) != EOF) {
+	while (getline_fn(line, stdin) != EOF) {
 		char *ptr, *tab;
 		char *path_name;
 		struct object_id oid;
@@ -39,8 +39,8 @@ int read_index_info(int nul_term_line, each_index_info_fn fn, void *cbdata)
 		 * index file and matches "git ls-files --stage" output.
 		 */
 		errno = 0;
-		ul = strtoul(buf.buf, &ptr, 8);
-		if (ptr == buf.buf || *ptr != ' '
+		ul = strtoul(line->buf, &ptr, 8);
+		if (ptr == line->buf || *ptr != ' '
 		    || errno || (unsigned int) ul != ul)
 			goto bad_line;
 		mode = ul;
@@ -81,10 +81,12 @@ int read_index_info(int nul_term_line, each_index_info_fn fn, void *cbdata)
 		continue;
 
 	bad_line:
-		die("malformed input line '%s'", buf.buf);
+		ret = INDEX_INFO_UNRECOGNIZED_LINE;
+		break;
 	}
-	strbuf_release(&buf);
 	strbuf_release(&uq);
+	if (!ret)
+		strbuf_reset(line);
 
 	return ret;
 }
diff --git a/index-info.h b/index-info.h
index d650498325a..9258011462d 100644
--- a/index-info.h
+++ b/index-info.h
@@ -5,7 +5,10 @@
 
 typedef int (*each_index_info_fn)(unsigned int, struct object_id *, int, const char *, void *);
 
+#define INDEX_INFO_UNRECOGNIZED_LINE 1
+
 /* Iterate over parsed index info from stdin */
-int read_index_info(int nul_term_line, each_index_info_fn fn, void *cbdata);
+int read_index_info(int nul_term_line, each_index_info_fn fn, void *cbdata,
+		    struct strbuf *line);
 
 #endif /* INDEX_INFO_H */
-- 
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