Add buildscript depdb builtin 'env' command

6 files changed, 65 insertions, 18 deletions

diff --git a/libbuild2/build/script/parser.cxx b/libbuild2/build/script/parser.cxx
index 4c11688..372c622 100644
--- a/libbuild2/build/script/parser.cxx
+++ b/libbuild2/build/script/parser.cxx
@@ -481,7 +481,7 @@ namespace build2
             next (t, tt);
 
             if (tt != type::word ||
-                (v != "clear" && v != "hash" && v != "string"))
+                (v != "clear" && v != "hash" && v != "string" && v != "env"))
             {
               fail (get_location (t))
                 << "expected 'depdb' builtin command instead of " << t;
@@ -950,6 +950,33 @@ namespace build2
                       << "'depdb string' argument change forcing update of "
                       << ctx.env.target;});
             }
+            else if (cmd == "env")
+            {
+              sha256 cs;
+              const char* pf ("invalid 'depdb env' argument: ");
+
+              try
+              {
+                // Skip <cmd>.
+                //
+                for (auto i (ns.begin () + 1); i != ns.end (); ++i)
+                {
+                  string vn (convert<string> (move (*i)));
+                  build2::script::verify_environment_var_name (vn, pf, ll);
+                  hash_environment (cs, vn);
+                }
+              }
+              catch (const invalid_argument& e)
+              {
+                fail (ll) << pf << e;
+              }
+
+              if (ctx.dd.expect (cs.string ()) != nullptr)
+                l4 ([&] {
+                    ctx.trace (ll)
+                      << "'depdb env' environment change forcing update of "
+                      << ctx.env.target;});
+            }
             else
               assert (false);
           }
diff --git a/libbuild2/build/script/parser.hxx b/libbuild2/build/script/parser.hxx
index b5a45ca..15429e3 100644
--- a/libbuild2/build/script/parser.hxx
+++ b/libbuild2/build/script/parser.hxx
@@ -194,13 +194,16 @@ namespace build2
         // The depdb builtin can be used to change the default dependency
         // change tracking:
         //
-        // depdb clear         - Cancels the default variables, targets, and
-        //                       prerequisites change tracking. Can only be
-        //                       the first depdb builtin call.
+        // depdb clear           - Cancel the default variables, targets, and
+        //                         prerequisites change tracking. Can only be
+        //                         the first depdb builtin call.
         //
-        // depdb hash <args>  - Track the argument list change as a hash.
+        // depdb hash <args>     - Track the argument list change as a hash.
         //
-        // depdb string <arg> - Track the argument (single) change as string.
+        // depdb string <arg>    - Track the argument (single) change as string.
+        //
+        // depdb env <var-names> - Track the environment variables change as a
+        //                         hash.
         //
         optional<location> depdb_clear_;    // 'depdb clear' location if any.
         lines              depdb_preamble_; // Note: excludes 'depdb clear'.
diff --git a/libbuild2/script/parser.cxx b/libbuild2/script/parser.cxx
index 41d3092..ebfd5fc 100644
--- a/libbuild2/script/parser.cxx
+++ b/libbuild2/script/parser.cxx
@@ -1437,7 +1437,7 @@ namespace build2
         }
         else if (optional<string> v = str ("--unset", "-u"))
         {
-          verify_environment_var_name (*v, o.c_str (), "env: ", i->second);
+          verify_environment_var_name (*v, "env: ", i->second, o.c_str ());
 
           r.variables.add (move (*v));
         }
diff --git a/libbuild2/script/run.cxx b/libbuild2/script/run.cxx
index 3faa35c..f36e979 100644
--- a/libbuild2/script/run.cxx
+++ b/libbuild2/script/run.cxx
@@ -781,7 +781,7 @@ namespace build2
         //
         auto verify_name = [&ll] (const string& name, const char* opt)
         {
-          verify_environment_var_name (name, opt, "export: ", ll);
+          verify_environment_var_name (name, "export: ", ll, opt);
         };
 
         // Parse options (variable set/unset cleanups and unsets).
diff --git a/libbuild2/script/script.cxx b/libbuild2/script/script.cxx
index db53418..298d71f 100644
--- a/libbuild2/script/script.cxx
+++ b/libbuild2/script/script.cxx
@@ -818,18 +818,34 @@ namespace build2
     //
     void
     verify_environment_var_name (const string& name,
-                                 const char* opt,
                                  const char* prefix,
-                                 const location& l)
+                                 const location& l,
+                                 const char* opt)
     {
       if (name.empty ())
-        fail (l) << prefix << "empty value for option " << opt;
+      {
+        diag_record dr (fail (l));
+        dr << prefix << "empty ";
+
+        if (opt == nullptr)
+          dr << "variable name";
+        else
+          dr << "value for option " << opt;
+      }
 
       if (name.find ('=') != string::npos)
-        fail (l) << prefix << "invalid value '" << name << "' for option "
-                 << opt << ": contains '='";
-    }
+      {
+        diag_record dr (fail (l));
+        dr << prefix << "invalid ";
+
+        if (opt == nullptr)
+          dr << "variable name '" << name << "'";
+        else
+          dr << "value '" << name << "' for option " << opt;
 
+        dr << ": contains '='";
+      }
+    }
 
     void
     verify_environment_var_assignment (const string& var,
diff --git a/libbuild2/script/script.hxx b/libbuild2/script/script.hxx
index b4cb7fc..dd31e33 100644
--- a/libbuild2/script/script.hxx
+++ b/libbuild2/script/script.hxx
@@ -569,14 +569,15 @@ namespace build2
 
     // Helpers.
     //
-    // Issue diagnostics with the specified prefix and fail if the string is
-    // not a valid variable name or assignment (empty, etc).
+    // Issue diagnostics with the specified prefix and fail if the string
+    // (potentially an option value) is not a valid variable name or
+    // assignment (empty, etc).
     //
     void
     verify_environment_var_name (const string&,
-                                 const char* opt,
                                  const char* prefix,
-                                 const location&);
+                                 const location&,
+                                 const char* opt = nullptr);
 
     void
     verify_environment_var_assignment (const string&,