fix(frontends/lean/dependencies): take relative paths into account when computing dependencies

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/frontends/lean/dependencies.cpp

@@ -14,11 +14,15 @@ Author: Leonardo de Moura
 namespace lean {
 void display_deps(environment const & env, std::ostream & out, char const * fname) {
     name import("import");
+    name period(".");
     std::ifstream in(fname);
     if (in.bad() || in.fail())
         throw exception(sstream() << "failed to open file '" << fname << "'");
     scanner s(in, fname);
-    bool import_args = false;
+    optional<unsigned> k;
+    std::string base = dirname(fname);
+    bool import_prefix = false;
+    bool import_args   = false;
     while (true) {
         scanner::token_kind t = scanner::token_kind::Identifier;
         try {
@@ -29,18 +33,28 @@ void display_deps(environment const & env, std::ostream & out, char const * fnam
         if (t == scanner::token_kind::Eof) {
             return;
         } else if (t == scanner::token_kind::CommandKeyword && s.get_token_info().value() == import) {
+            k = optional<unsigned>();
+            import_prefix = true;
+        } else if (import_prefix && t == scanner::token_kind::Keyword && s.get_token_info().value() == period) {
+            if (!k)
+                k = 0;
+            else
+                k = *k + 1;
+        } else if ((import_prefix || import_args) && t == scanner::token_kind::Identifier) {
             import_args = true;
-        } else if (import_args == true && t == scanner::token_kind::Identifier) {
+            std::string m_name = find_file(base, k, name_to_file(s.get_name_val()), {".lean", ".olean", ".lua"});
-            std::string m_name = find_file(name_to_file(s.get_name_val()), {".lean", ".olean", ".lua"});
             int last_idx = m_name.find_last_of(".");
             std::string rawname = m_name.substr(0, last_idx);
             std::string ext = m_name.substr(last_idx);
             if (ext == ".lean")
                 m_name = rawname + ".olean";
             display_path(out, m_name);
+            k = optional<unsigned>();
+            import_prefix = true;
             out << "\n";
         } else {
-            import_args = false;
+            import_args   = false;
+            import_prefix = false;
         }
     }
 }

src/util/lean_path.cpp

@@ -245,21 +245,28 @@ std::string find_file(std::string fname, std::initializer_list<char const *> con
     throw exception(sstream() << "file '" << fname << "' not found in the LEAN_PATH");
 }
 
-std::string find_file(std::string const & base, optional<unsigned> const & rel, name const & fname, char const * ext) {
+std::string find_file(std::string const & base, optional<unsigned> const & rel, name const & fname,
+                      std::initializer_list<char const *> const & extensions) {
     if (!rel) {
-        return find_file(fname.to_string(g_sep_str.c_str()), {ext});
+        return find_file(fname.to_string(g_sep_str.c_str()), extensions);
     } else {
         auto path = base;
         for (unsigned i = 0; i < *rel; i++) {
             path += g_sep;
             path += "..";
         }
-        if (auto r = check_file(path, fname.to_string(g_sep_str.c_str()), ext))
+        for (auto ext : extensions) {
-            return *r;
+            if (auto r = check_file(path, fname.to_string(g_sep_str.c_str()), ext))
+                return *r;
+        }
         throw exception(sstream() << "file '" << fname << "' not found at '" << path << "'");
     }
 }
 
+std::string find_file(std::string const & base, optional<unsigned> const & k, name const & fname, char const * ext) {
+    return find_file(base, k, fname, {ext});
+}
+
 std::string find_file(std::string fname) {
     return find_file(fname, {".olean", ".lean", ".lua"});
 }

src/util/lean_path.h

@@ -24,6 +24,8 @@ std::string find_file(name const & fname);
 std::string find_file(name const & fname, std::initializer_list<char const *> const & exts);
 
 /** \brief \brief Similar to previous find_file, but if k is not none then search at the k-th parent of base. */
+std::string find_file(std::string const & base, optional<unsigned> const & rel, name const & fname,
+                      std::initializer_list<char const *> const & extensions);
 std::string find_file(std::string const & base, optional<unsigned> const & k, name const & fname, char const * ext);
 
 /** \brief Return true iff fname ends with ".lean" */