write_entry(): fix misuses of `path` in error messages

The variables `path` and `ce->name`, at write_entry(), usually have the
same contents, but that's not the case when using a checkout prefix or
writing to a tempfile. (In fact, `path` will be either empty or dirty
when writing to a tempfile.) Therefore, these variables cannot be used
interchangeably. In this sense, fix wrong uses of `path` in error
messages where it should really be `ce->name`, and add some regression
tests. (Note: there doesn't seem to be any misuse in the other way
around.)

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

entry.c

@@ -282,7 +282,7 @@ static int write_entry(struct cache_entry *ce,
 		new_blob = read_blob_entry(ce, &size);
 		if (!new_blob)
 			return error("unable to read sha1 file of %s (%s)",
-				     path, oid_to_hex(&ce->oid));
+				     ce->name, oid_to_hex(&ce->oid));
 
 		/*
 		 * We can't make a real symlink; write out a regular file entry
@@ -309,7 +309,7 @@ static int write_entry(struct cache_entry *ce,
 			new_blob = read_blob_entry(ce, &size);
 			if (!new_blob)
 				return error("unable to read sha1 file of %s (%s)",
-					     path, oid_to_hex(&ce->oid));
+					     ce->name, oid_to_hex(&ce->oid));
 		}
 
 		/*
@@ -354,7 +354,7 @@ static int write_entry(struct cache_entry *ce,
 
 	case S_IFGITLINK:
 		if (to_tempfile)
-			return error("cannot create temporary submodule %s", path);
+			return error("cannot create temporary submodule %s", ce->name);
 		if (mkdir(path, 0777) < 0)
 			return error("cannot create submodule directory %s", path);
 		sub = submodule_from_ce(ce);
@@ -365,7 +365,7 @@ static int write_entry(struct cache_entry *ce,
 		break;
 
 	default:
-		return error("unknown file mode for %s in index", path);
+		return error("unknown file mode for %s in index", ce->name);
 	}
 
 finish:

t/t2006-checkout-index-basic.sh

@@ -32,4 +32,27 @@ test_expect_success 'checkout-index reports errors (stdin)' '
 	test_i18ngrep not.in.the.cache stderr
 '
 
+test_expect_success 'checkout-index --temp correctly reports error on missing blobs' '
+	test_when_finished git reset --hard &&
+	missing_blob=$(echo "no such blob here" | git hash-object --stdin) &&
+	cat >objs <<-EOF &&
+	100644 $missing_blob	file
+	120000 $missing_blob	symlink
+	EOF
+	git update-index --index-info <objs &&
+
+	test_must_fail git checkout-index --temp symlink file 2>stderr &&
+	test_i18ngrep "unable to read sha1 file of file ($missing_blob)" stderr &&
+	test_i18ngrep "unable to read sha1 file of symlink ($missing_blob)" stderr
+'
+
+test_expect_success 'checkout-index --temp correctly reports error for submodules' '
+	git init sub &&
+	test_commit -C sub file &&
+	git submodule add ./sub &&
+	git commit -m sub &&
+	test_must_fail git checkout-index --temp sub 2>stderr &&
+	test_i18ngrep "cannot create temporary submodule sub" stderr
+'
+
 test_done