ccanlint: add test to look for modules we use but don't list in _info.

tools/ccanlint/tests/depends_accurate.c

+#include <tools/ccanlint/ccanlint.h>
+#include <tools/tools.h>
+#include <ccan/talloc/talloc.h>
+#include <ccan/str/str.h>
+#include <ccan/foreach/foreach.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <limits.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <err.h>
+#include <string.h>
+#include <ctype.h>
+
+static char *strip_spaces(const void *ctx, char *line)
+{
+	char *p = talloc_strdup(ctx, line);
+	unsigned int i, j;
+
+	for (i = 0, j = 0; p[i]; i++) {
+		if (!isspace(p[i]))
+			p[j++] = p[i];
+	}
+	p[j] = '\0';
+	return p;
+}
+
+static bool has_dep(struct manifest *m, const char *depname, bool tap_ok)
+{
+	struct ccan_file *f;
+
+	if (tap_ok && streq(depname, "ccan/tap"))
+		return true;
+
+	/* We can include ourselves, of course. */
+	if (streq(depname + strlen("ccan/"), m->basename))
+		return true;
+
+	list_for_each(&m->dep_dirs, f, list) {
+		if (streq(f->name, depname))
+			return true;
+	}
+	return false;
+}
+
+static void *check_depends_accurate(struct manifest *m,
+				    bool keep,
+				    unsigned int *timeleft)
+{
+	struct list_head *list;
+	char *report = talloc_strdup(m, "");
+
+	foreach_ptr(list, &m->c_files, &m->h_files,
+		    &m->run_tests, &m->api_tests,
+		    &m->compile_ok_tests, &m->compile_fail_tests,
+		    &m->other_test_c_files) {
+		struct ccan_file *f;
+		bool tap_ok;
+
+		/* Including ccan/tap is fine for tests. */
+		tap_ok =  (list != &m->c_files && list != &m->h_files);
+
+		list_for_each(list, f, list) {
+			unsigned int i;
+			char **lines = get_ccan_file_lines(f);
+
+			for (i = 0; lines[i]; i++) {
+				char *p;
+				if (lines[i][strspn(lines[i], " \t")] != '#')
+					continue;
+				p = strip_spaces(f, lines[i]);
+				if (!strstarts(p, "#include<ccan/")
+				    && !strstarts(p, "#include\"ccan/"))
+					continue;
+				p += strlen("#include\"");
+				if (!strchr(strchr(p, '/') + 1, '/'))
+					continue;
+				*strchr(strchr(p, '/') + 1, '/') = '\0';
+				if (!has_dep(m, p, tap_ok))
+					report = talloc_asprintf_append(report,
+					       "%s:%u:%s\n",
+					       f->name, i+1, lines[i]);
+			}
+		}
+	}
+
+	if (streq(report, "")) {
+		talloc_free(report);
+		report = NULL;
+	}
+	return report;
+}
+
+static const char *describe_depends_accurage(struct manifest *m,
+					     void *check_result)
+{
+	return talloc_asprintf(check_result, 
+			       "You include ccan modules you don't list as dependencies:\n"
+			       "%s", (char *)check_result);
+}
+
+struct ccanlint depends_accurate = {
+	.key = "depends-accurate",
+	.name = "Module's CCAN dependencies are the only ccan files #included",
+	.total_score = 1,
+	.check = check_depends_accurate,
+	.describe = describe_depends_accurage,
+};
+
+REGISTER_TEST(depends_accurate, &depends_exist, NULL);