Rework configuration file loading to be more consistent. Any configuration file can be set (or disabled) with --xxx-config=. --config= overrides all configuration files.

doc/src/overview.xml

@@ -449,6 +449,8 @@ actions create-file-from-another
       </tgroup>
     </table>
 
+    <para>Any of these files may also be overridden <link linkend="bbv2.reference.init.options.config">on the command line</link></para>
+
     <tip>
       <para>
         You can use the <command>--debug-configuration</command> option to
@@ -785,6 +787,38 @@ b2 toolset=gcc variant=debug optimization=space
             </listitem>
           </varlistentry>
 
+          <varlistentry id="bbv2.reference.init.options.config">
+            <term><option>--config=<replaceable>filename</replaceable></option></term>
+            <listitem>
+              <indexterm><primary>config</primary></indexterm>
+              <para>Override all <link linkend="bbv2.overview.configuration">configuration files</link></para>
+            </listitem>
+          </varlistentry>
+
+          <varlistentry>
+            <term><option>--site-config=<replaceable>filename</replaceable></option></term>
+            <listitem>
+              <indexterm><primary>site-config.jam</primary></indexterm>
+              <para>Override the default <link linkend="bbv2.overview.configuration">site-config.jam</link></para>
+            </listitem>
+          </varlistentry>
+
+          <varlistentry>
+            <term><option>--user-config=<replaceable>filename</replaceable></option></term>
+            <listitem>
+              <indexterm><primary>user-config.jam</primary></indexterm>
+              <para>Override the default <link linkend="bbv2.overview.configuration">user-config.jam</link></para>
+            </listitem>
+          </varlistentry>
+
+          <varlistentry>
+            <term><option>--project-config=<replaceable>filename</replaceable></option></term>
+            <listitem>
+              <indexterm><primary>project-config.jam</primary></indexterm>
+              <para>Override the default <link linkend="bbv2.overview.configuration">project-config.jam</link></para>
+            </listitem>
+          </varlistentry>
+
           <varlistentry>
             <term><option>--debug-configuration</option></term>
             <listitem>

src/build-system.jam

@@ -272,6 +272,35 @@ local rule load-config ( module-name : filename : path + : must-find ? )
     return $(where) ;
 }
 
+# Parses options of the form --xxx-config=path/to/config.jam
+# and environmental variables of the form BOOST_BUILD_XXX_CONFIG.
+# If not found, returns an empty list.  The option may be
+# explicitly set to the empty string, in which case, handle-config-option
+# will return "".
+#
+local rule handle-config-option ( name : env ? )
+{
+    local result = [ MATCH ^--$(name)=(.*)$ : $(.argv) ] ;
+    if ! $(result)-is-defined && $(env)
+    {
+        result = [ os.environ $(env) ] ;
+    }
+    # Special handling for the case when the OS does not strip the quotes
+    # around the file name, as is the case when using Cygwin bash.
+    result = [ utility.unquote $(result[-1]) ] ;
+    if ! $(result)
+    {
+        return $(result) ;
+    }
+    # Treat explicitly entered user paths as native OS path
+    # references and, if non-absolute, root them at the current
+    # working directory.
+    result = [ path.make $(result) ] ;
+    result = [ path.root $(result) [ path.pwd ] ] ;
+    result = [ path.native $(result) ] ;
+    return $(result) ;
+}
+
 
 # Loads all the configuration files used by Boost Build in the following order:
 #
@@ -282,11 +311,21 @@ local rule load-config ( module-name : filename : path + : must-find ? )
 # files will not be. If a relative path is specified, file is searched for in
 # the current folder.
 #
+#   -- all-config --
+#   Loaded only if specified on the command-line using the --config command
+# line option.  If a file name is specified, it must exist and replaces all
+# other configuration files.  If an empty file name is passed, no configuration
+# files will be loaded.
+#
 #   -- site-config --
-#   Always named site-config.jam. Will only be found if located on the system
+#   Named site-config.jam by default or may be named explicitly using the
-# root path (Windows), /etc (non-Windows), user's home folder or the Boost Build
+# --site-config command-line option.  If named explicitly, the file is found
-# path, in that order. Not loaded in case the test-config configuration file is
+# relative to the current working directory and must exist.  If the default one
-# loaded or the --ignore-site-config command-line option is specified.
+# is used then it is searched for in the system root path (Windows),
+# /etc (non-Windows), user's home folder or the Boost Build path, in that
+# order.  Not loaded in case the test-config configuration file is loaded,
+# the file is explicitly set to the empty string or the --ignore-site-config
+# command-line option is specified.
 #
 #   -- user-config --
 #   Named user-config.jam by default or may be named explicitly using the
@@ -299,8 +338,12 @@ local rule load-config ( module-name : filename : path + : must-find ? )
 # file must exist.
 #
 #   -- project-config --
-#   Always named project-config.jam. Looked up in the current working folder and
+#   Named project-config.jam. Looked up in the current working folder and
-# then upwards through its parents up to the root folder.
+# then upwards through its parents up to the root folder.  It may also be
+# named explicitly using the --project-config command-line option.  If a file
+# is specified explicitly, it is found relative to the current working
+# directory and must exist.  If an empty file name is passed, project-config
+# will not be loaded.
 #
 # Test configurations have been added primarily for use by Boost Build's
 # internal unit testing system but may be used freely in other places as well.
@@ -310,14 +353,11 @@ local rule load-configuration-files
     # Flag indicating that site configuration should not be loaded.
     local ignore-site-config =
         [ MATCH ^(--ignore-site-config)$ : $(.argv) ] ;
+    local ignore-user-config ;
+    local ignore-project-config ;
 
     initialize-config-module test-config ;
-    local test-config = [ MATCH ^--test-config=(.*)$ : $(.argv) ] ;
+    local test-config = [ handle-config-option test-config ] ;
-    local uq = [ MATCH \"(.*)\" : $(test-config) ] ;
-    if $(uq)
-    {
-        test-config = $(uq) ;
-    }
     if $(test-config)
     {
         local where = [ load-config test-config : $(test-config:BS) :
@@ -330,12 +370,32 @@ local rule load-configuration-files
                 ECHO "notice: be ignored due to the test configuration being"
                     "loaded." ;
             }
+            ignore-site-config = true ;
+            ignore-user-config = true ;
         }
-        else
+    }
+
+    initialize-config-module all-config ;
+    local all-config = [ handle-config-option config ] ;
+    if $(all-config)
+    {
+        load-config all-config : $(all-config:D=) : $(all-config:D) : required ;
+        if $(.debug-config)
         {
-            test-config = ;
+            ECHO "notice: Regular configuration files will be ignored due" ;
+            ECHO "notice: to the global configuration being loaded." ;
         }
     }
+    if $(all-config)-is-defined
+    {
+        if $(.debug-config) && ! $(all-config)
+        {
+            ECHO "notice: Configuration file loading explicitly disabled." ;
+        }
+        ignore-site-config = true ;
+        ignore-user-config = true ;
+        ignore-project-config = true ;
+    }
 
     local user-path = [ os.home-directories ] [ os.environ BOOST_BUILD_PATH ] ;
     local site-path = /etc $(user-path) ;
@@ -344,55 +404,52 @@ local rule load-configuration-files
         site-path = [ modules.peek : SystemRoot ] $(user-path) ;
     }
 
-    if $(.debug-config) && ! $(test-config) && $(ignore-site-config)
+    if $(.debug-config) && $(ignore-site-config) = --ignore-site-config
     {
         ECHO "notice: Site configuration files will be ignored due to the" ;
         ECHO "notice: --ignore-site-config command-line option." ;
     }
 
     initialize-config-module site-config ;
-    if ! $(test-config) && ! $(ignore-site-config)
+    if ! $(ignore-site-config)
     {
-        load-config site-config : site-config.jam : $(site-path) ;
+        local site-config = [ handle-config-option site-config ] ;
+        if $(site-config)
+        {
+            load-config site-config : $(site-config:D=) : $(site-config:D)
+                : must-exist ;
+        }
+        else if ! $(site-config)-is-defined
+        {
+            load-config site-config : site-config.jam : $(site-path) ;
+        }
+        else if $(.debug-config)
+        {
+            ECHO notice: Site configuration file loading explicitly disabled. ;
+        }
     }
 
     initialize-config-module user-config ;
-    if ! $(test-config)
+    if ! $(ignore-user-config)
     {
-        local user-config = [ MATCH ^--user-config=(.*)$ : $(.argv) ] ;
+        local user-config =
-        user-config = $(user-config[-1]) ;
+            [ handle-config-option user-config : BOOST_BUILD_USER_CONFIG ] ;
-        user-config ?= [ os.environ BOOST_BUILD_USER_CONFIG ] ;
-        # Special handling for the case when the OS does not strip the quotes
-        # around the file name, as is the case when using Cygwin bash.
-        user-config = [ utility.unquote $(user-config) ] ;
-        local explicitly-requested = $(user-config) ;
-        user-config ?= user-config.jam ;
 
         if $(user-config)
         {
-            if $(explicitly-requested)
+            if $(.debug-config)
             {
-                # Treat explicitly entered user paths as native OS path
+                ECHO notice: Loading explicitly specified user configuration
-                # references and, if non-absolute, root them at the current
+                    file: ;
-                # working directory.
+                ECHO "    $(user-config)" ;
-                user-config = [ path.make $(user-config) ] ;
-                user-config = [ path.root $(user-config) [ path.pwd ] ] ;
-                user-config = [ path.native $(user-config) ] ;
-
-                if $(.debug-config)
-                {
-                    ECHO notice: Loading explicitly specified user configuration
-                        file: ;
-                    ECHO "    $(user-config)" ;
-                }
-
-                load-config user-config : $(user-config:BS) : $(user-config:D)
-                    : must-exist ;
-            }
-            else
-            {
-                load-config user-config : $(user-config) : $(user-path) ;
             }
+
+            load-config user-config : $(user-config:D=) : $(user-config:D)
+                : must-exist ;
+        }
+        else if ! $(user-config)-is-defined
+        {
+            load-config user-config : user-config.jam : $(user-path) ;
         }
         else if $(.debug-config)
         {
@@ -406,15 +463,33 @@ local rule load-configuration-files
     # - We need to load project-config.jam before Jamroot
     # - We probably need to load project-config.jam even if there is no Jamroot
     #   - e.g. to implement automake-style out-of-tree builds.
-    local file = [ path.glob "." : project-config.jam ] ;
+    if ! $(ignore-project-config)
-    if ! $(file)
     {
-        file = [ path.glob-in-parents "." : project-config.jam ] ;
+        local project-config = [ handle-config-option project-config ] ;
-    }
+        if $(project-config)
-    if $(file)
+        {
-    {
+            initialize-config-module project-config : $(project-config:D=) ;
-        initialize-config-module project-config : $(file:D) ;
+            load-config project-config : $(project-config:D=)
-        load-config project-config : project-config.jam : $(file:D) ;
+                : $(project-config:D) : must-exist ;
+        }
+        else if ! $(project-config)-is-defined
+        {
+            local file = [ path.glob "." : project-config.jam ] ;
+            if ! $(file)
+            {
+                file = [ path.glob-in-parents "." : project-config.jam ] ;
+            }
+            if $(file)
+            {
+                initialize-config-module project-config : $(file:D) ;
+                load-config project-config : project-config.jam : $(file:D) ;
+            }
+        }
+        else if $(.debug-config)
+        {
+            ECHO notice: Project configuration file loading explicitly
+                disabled. ;
+        }
     }
 
     project.end-load ;

src/build/project.jam

@@ -441,7 +441,7 @@ rule initialize (
     local jamroot ;
 
     local parent-module ;
-    if $(module-name) = test-config
+    if $(module-name) in test-config all-config
     {
         # No parent.
     }
@@ -502,7 +502,7 @@ rule initialize (
         }
         else
         {
-            local cfgs = project site test user ;
+            local cfgs = project site test user all ;
             if ! $(module-name) in $(cfgs)-config
             {
                 # This is a standalone project with known location. Set its

test/configuration.py

@@ -8,6 +8,7 @@
 # Test Boost Build configuration file handling.
 
 import BoostBuild
+import TestCmd
 
 import os
 import os.path
@@ -316,6 +317,71 @@ for x in $(names)
         t.cleanup()
 
 
+def test_site_config():
+    # Ignore user-config, just in case it depends on the user's site-config.jam
+    t = BoostBuild.Tester(["--user-config="], use_test_config=False,
+                          pass_toolset=0)
+    # We can immediately exit after we finish loading the config files
+    t.write("Jamroot", "EXIT Done : 0 ;")
+    t.write("my-site-config.jam", "ECHO Loaded my-site-config ;")
+
+    t.run_build_system(["--site-config=my-site-config.jam"],
+                       stdout="Loaded my-site-config\nDone\n")
+
+    t.run_build_system(["--ignore-site-config", "--debug-configuration"])
+    t.expect_output_lines("""\
+notice: Site configuration files will be ignored due to the
+notice: --ignore-site-config command-line option.""")
+
+    t.run_build_system(["--site-config=", "--debug-configuration"])
+    t.expect_output_lines("""\
+notice: Site configuration file loading explicitly disabled.""")
+
+    t.cleanup()
+
+def test_global_config():
+    t = BoostBuild.Tester(use_test_config=False, pass_toolset=0)
+    t.write("my-config.jam", "ECHO Loading my-config ;")
+    t.write("Jamroot", "EXIT Done : 0 ;")
+    t.write("project-config.jam", "ECHO bad ;")
+    t.run_build_system(["--config=my-config.jam", "--debug-configuration"],
+                       match=TestCmd.match_re, stdout=
+r"""notice: found boost-build\.jam at .*
+notice: loading Boost\.Build from .*
+notice: Searching '.*' for all-config configuration file 'my-config\.jam'\.
+notice: Loading all-config configuration file 'my-config\.jam' from '.*'\.
+Loading my-config
+notice: Regular configuration files will be ignored due
+notice: to the global configuration being loaded\.
+Done
+""")
+    t.run_build_system(["--config=", "--debug-configuration"],
+                       match=TestCmd.match_re, stdout=
+r"""notice: found boost-build\.jam at .*
+notice: loading Boost\.Build from .*
+notice: Configuration file loading explicitly disabled.
+Done
+""")
+    t.cleanup()
+
+def test_project_config():
+    t = BoostBuild.Tester(["--user-config=", "--site-config="],
+                          use_test_config=False, pass_toolset=False)
+    t.write("Jamroot", "EXIT Done : 0 ;")
+    t.write("project-config.jam", "ECHO Loading Root ;")
+    t.write("my-project-config.jam", "ECHO Loading explicit ;")
+    t.write("sub/project-config.jam", "ECHO Loading subdir ;")
+    t.write("sub/Jamfile", "")
+
+    t.run_build_system(stdout="Loading Root\nDone\n")
+    t.run_build_system(subdir="sub", stdout="Loading subdir\nDone\n")
+    t.rm("sub/project-config.jam")
+    t.run_build_system(subdir="sub", stdout="Loading Root\nDone\n")
+    t.run_build_system(["--project-config=my-project-config.jam"],
+                       stdout="Loading explicit\nDone\n")
+
+    t.cleanup()
+
 ###############################################################################
 #
 # main()
@@ -326,3 +392,6 @@ for x in $(names)
 canSetEmptyEnvironmentVariable = _canSetEmptyEnvironmentVariable()
 
 test_user_configuration()
+test_site_config()
+test_global_config()
+test_project_config()