In -W style mode, check .Xr links along the full manpath because

that is more useful for validating manuals of non-base software.
Nothing changes in -W all mode: by default for -T lint, we still
assume we want to check base system conventions, including usually
not wanting to link to non-base manual pages.

The use case, a partial idea how to handle it, and a preliminary
patch was originally presented by kn@, then refined by me.
Final patch tested and OK'ed by kn@.

4 files changed, 54 insertions, 30 deletions

diff --git a/main.c b/main.c
index db2ed168..58954f61 100644
--- a/main.c
+++ b/main.c
@@ -1,6 +1,6 @@
 /* $Id$ */
 /*
- * Copyright (c) 2010-2012, 2014-2020 Ingo Schwarze <schwarze@openbsd.org>
+ * Copyright (c) 2010-2012, 2014-2021 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
  * Copyright (c) 2010 Joerg Sonnenberger <joerg@netbsd.org>
  *
@@ -93,7 +93,7 @@ struct	outstate {
 
 int			  mandocdb(int, char *[]);
 
-static	void		  check_xr(void);
+static	void		  check_xr(struct manpaths *);
 static	int		  fs_lookup(const struct manpaths *,
 				size_t ipath, const char *,
 				const char *, const char *,
@@ -104,7 +104,7 @@ static	int		  fs_search(const struct mansearch *,
 static	void		  glob_esc(char **, const char *, const char *);
 static	void		  outdata_alloc(struct outstate *, struct manoutput *);
 static	void		  parse(struct mparse *, int, const char *,
-				struct outstate *, struct manoutput *);
+				struct outstate *, struct manconf *);
 static	void		  passthrough(int, int);
 static	void		  process_onefile(struct mparse *, struct manpage *,
 				int, struct outstate *, struct manconf *);
@@ -452,7 +452,8 @@ main(int argc, char *argv[])
 
 	/* Read the configuration file. */
 
-	if (search.argmode != ARG_FILE)
+	if (search.argmode != ARG_FILE ||
+	    mandoc_msg_getmin() == MANDOCERR_STYLE)
 		manconf_parse(&conf, conf_file, defpaths, auxpaths);
 
 	/* man(1): Resolve each name individually. */
@@ -865,7 +866,7 @@ process_onefile(struct mparse *mp, struct manpage *resp, int startdir,
 	}
 
 	if (resp->form == FORM_SRC)
-		parse(mp, fd, resp->file, outst, &conf->output);
+		parse(mp, fd, resp->file, outst, conf);
 	else {
 		passthrough(fd, conf->output.synopsisonly);
 		outst->had_output = 1;
@@ -886,8 +887,9 @@ process_onefile(struct mparse *mp, struct manpage *resp, int startdir,
 
 static void
 parse(struct mparse *mp, int fd, const char *file,
-    struct outstate *outst, struct manoutput *outconf)
+    struct outstate *outst, struct manconf *conf)
 {
+	static struct manpaths	 basepaths;
 	static int		 previous;
 	struct roff_meta	*meta;
 
@@ -913,7 +915,7 @@ parse(struct mparse *mp, int fd, const char *file,
 		return;
 
 	if (outst->outdata == NULL)
-		outdata_alloc(outst, outconf);
+		outdata_alloc(outst, &conf->output);
 	else if (outst->outtype == OUTT_HTML)
 		html_reset(outst->outdata);
 
@@ -970,24 +972,25 @@ parse(struct mparse *mp, int fd, const char *file,
 			break;
 		}
 	}
-	if (outconf->tag != NULL && outconf->tag_found == 0 &&
-	    tag_exists(outconf->tag))
-		outconf->tag_found = 1;
-	if (mandoc_msg_getmin() < MANDOCERR_STYLE)
-		check_xr();
+	if (conf->output.tag != NULL && conf->output.tag_found == 0 &&
+	    tag_exists(conf->output.tag))
+		conf->output.tag_found = 1;
+
+	if (mandoc_msg_getmin() < MANDOCERR_STYLE) {
+		if (basepaths.sz == 0)
+			manpath_base(&basepaths);
+		check_xr(&basepaths);
+	} else if (mandoc_msg_getmin() < MANDOCERR_WARNING)
+		check_xr(&conf->manpath);
 }
 
 static void
-check_xr(void)
+check_xr(struct manpaths *paths)
 {
-	static struct manpaths	 paths;
 	struct mansearch	 search;
 	struct mandoc_xr	*xr;
 	size_t			 sz;
 
-	if (paths.sz == 0)
-		manpath_base(&paths);
-
 	for (xr = mandoc_xr_get(); xr != NULL; xr = xr->next) {
 		if (xr->line == -1)
 			continue;
@@ -996,9 +999,9 @@ check_xr(void)
 		search.outkey = NULL;
 		search.argmode = ARG_NAME;
 		search.firstmatch = 1;
-		if (mansearch(&search, &paths, 1, &xr->name, NULL, &sz))
+		if (mansearch(&search, paths, 1, &xr->name, NULL, &sz))
 			continue;
-		if (fs_search(&search, &paths, xr->name, NULL, &sz) != -1)
+		if (fs_search(&search, paths, xr->name, NULL, &sz) != -1)
 			continue;
 		if (xr->count == 1)
 			mandoc_msg(MANDOCERR_XR_BAD, xr->line,
diff --git a/mandoc.1 b/mandoc.1
index ffc291dd..7bd0911a 100644
--- a/mandoc.1
+++ b/mandoc.1
@@ -1,6 +1,6 @@
 .\" $OpenBSD: mandoc.1,v 1.166 2020/02/15 15:28:01 schwarze Exp $
 .\"
-.\" Copyright (c) 2012, 2014-2020 Ingo Schwarze <schwarze@openbsd.org>
+.\" Copyright (c) 2012, 2014-2021 Ingo Schwarze <schwarze@openbsd.org>
 .\" Copyright (c) 2009, 2010, 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 .\"
 .\" Permission to use, copy, modify, and distribute this software for any
@@ -922,14 +922,6 @@ generated by CVS
 or
 .Ic NetBSD
 keyword substitution as conventionally used in these operating systems.
-.It Sy "referenced manual not found"
-.Pq mdoc
-An
-.Ic \&Xr
-macro references a manual page that is not found in the base system.
-The path to look for base system manuals is configurable at compile
-time and defaults to
-.Pa /usr/share/man : /usr/X11R6/man .
 .El
 .Ss Style suggestions
 .Bl -ohang
@@ -1016,6 +1008,35 @@ list contains two consecutive
 entries describing the same
 .Ic \&Er
 number.
+.It Sy "referenced manual not found"
+.Pq mdoc
+An
+.Ic \&Xr
+macro references a manual page that was not found.
+When running with
+.Fl W Cm base ,
+the search is restricted to the base system, by default to
+.Pa /usr/share/man : Ns Pa /usr/X11R6/man .
+This path can be configured at compile time using the
+.Dv MANPATH_BASE
+preprocessor macro.
+When running with
+.Fl W Cm style ,
+the search is done along the full search path as described in the
+.Xr man 1
+manual page, respecting the
+.Fl m
+and
+.Fl M
+command line options, the
+.Ev MANPATH
+environment variable, the
+.Xr man.conf 5
+file and falling back to the default of
+.Pa /usr/share/man : Ns Pa /usr/X11R6/man : Ns Pa /usr/local/man ,
+also configurable at compile time using the
+.Dv MANPATH_DEFAULT
+preprocessor macro.
 .It Sy "trailing delimiter"
 .Pq mdoc
 The last argument of an
diff --git a/mandoc.h b/mandoc.h
index 81941ffe..b6e5c981 100644
--- a/mandoc.h
+++ b/mandoc.h
@@ -54,7 +54,6 @@ enum	mandocerr {
 	MANDOCERR_ARCH_BAD,  /* unknown architecture: Dt ... arch */
 	MANDOCERR_OS_ARG,  /* operating system explicitly specified: Os ... */
 	MANDOCERR_RCS_MISSING, /* RCS id missing */
-	MANDOCERR_XR_BAD,  /* referenced manual not found: Xr name sec */
 
 	MANDOCERR_STYLE, /* ===== start of style suggestions ===== */
 
@@ -68,6 +67,7 @@ enum	mandocerr {
 	MANDOCERR_BX, /* consider using OS macro: macro */
 	MANDOCERR_ER_ORDER, /* errnos out of order: Er ... */
 	MANDOCERR_ER_REP, /* duplicate errno: Er ... */
+	MANDOCERR_XR_BAD,  /* referenced manual not found: Xr name sec */
 	MANDOCERR_DELIM, /* trailing delimiter: macro ... */
 	MANDOCERR_DELIM_NB, /* no blank before trailing delimiter: macro ... */
 	MANDOCERR_FI_SKIP, /* fill mode already enabled, skipping: fi */
diff --git a/mandoc_msg.c b/mandoc_msg.c
index 3ec86744..7a127331 100644
--- a/mandoc_msg.c
+++ b/mandoc_msg.c
@@ -55,7 +55,6 @@ static	const char *const type_message[MANDOCERR_MAX] = {
 	"unknown architecture",
 	"operating system explicitly specified",
 	"RCS id missing",
-	"referenced manual not found",
 
 	"generic style suggestion",
 
@@ -69,6 +68,7 @@ static	const char *const type_message[MANDOCERR_MAX] = {
 	"consider using OS macro",
 	"errnos out of order",
 	"duplicate errno",
+	"referenced manual not found",
 	"trailing delimiter",
 	"no blank before trailing delimiter",
 	"fill mode already enabled, skipping",