Add 'config_file = filename' RC file option - to enable recursive inclusion of config files. (#407)

henry2cox · web-flow · commit df03ba434eee · 2025-04-30T12:30:23.000-04:00
See discussion in PR #404 for a discussion of the feature and some potential use models. Signed-off-by: Henry Cox <henry.cox@mediatek.com>
diff --git a/lcovrc b/lcovrc
@@ -7,6 +7,14 @@
 # Note that this example script does not include all configuration options
 # see 'man lcovrc(5) for a complete list and usage description.
 
+# include some other config file
+#   e.g, user-specific options.  Note the environment variable expansion
+# config_file = $ENV{HOME}/.user_lcovrc
+#   or project specific - hard-coded from environment variable
+# config_file = /path/to/myproject/.lcovrc
+#   or in the current run directory
+# config_file = $ENV{PWD}/.lcovrc
+
 # Specify an external style sheet file (same as --css-file option of genhtml)
 #genhtml_css_file = gcov.css
 
diff --git a/lib/lcovutil.pm b/lib/lcovutil.pm
@@ -1009,57 +1009,6 @@ sub cleanup_callbacks
     }
 }
 
-#
-# apply_config(REF, ref)
-#
-# REF is a reference to a hash containing the following mapping:
-#
-#   key_string => var_ref
-#
-# where KEY_STRING is a keyword and VAR_REF is a reference to an associated
-# variable. If the global configuration hashes CONFIG or OPT_RC contain a value
-# for keyword KEY_STRING, VAR_REF will be assigned the value for that keyword.
-#
-# Return 1 if we set something
-
-sub _set_config($$$)
-{
-    my ($ref, $key, $value) = @_;
-    my $r = $ref->{$key};
-    my $t = ref($r);
-    if ('ARRAY' eq $t) {
-        info(2, "  append $value to list $key\n");
-        if ('ARRAY' eq ref($value)) {
-            push(@$r, @$value);
-        } else {
-            push(@$r, $value);
-        }
-    } else {
-        # opt is a scalar or not defined
-        #  only way for $value to NOT be an array is if there is a bug in
-        #  the caller such that a scalar ref was passed where a prior call
-        #  had passed a list ref for the same RC option name
-        die("unexpected ARRAY for $key value")
-            if ('ARRAY' eq ref($value));
-        $$r = $value;
-        info(2, "  assign $$r to $key\n");
-    }
-}
-
-sub apply_config($$)
-{
-    my ($ref, $config) = @_;
-    my $set_value = 0;
-    foreach (keys(%{$ref})) {
-        # if sufficiently verbose, could mention that key is ignored
-        next unless exists($config->{$_});
-        my $v = $config->{$_};
-        $set_value = 1;
-        _set_config($ref, $_, $v);    # write into options
-    }
-    return $set_value;
-}
-
 # use these list values from the RC file unless the option is
 #   passed on the command line
 my (@rc_filter, @rc_ignore, @rc_exclude_patterns,
@@ -1284,27 +1233,66 @@ sub warnDeprecated
     return $opt_used;
 }
 
+sub _set_config($$$)
+{
+    # write an RC configuration value - array or scalar
+    my ($ref, $key, $value) = @_;
+    my $r = $ref->{$key};
+    my $t = ref($r);
+    if ('ARRAY' eq $t) {
+        info(2, "  append $value to list $key\n");
+        if ('ARRAY' eq ref($value)) {
+            push(@$r, @$value);
+        } else {
+            push(@$r, $value);
+        }
+    } else {
+        # opt is a scalar or not defined
+        #  only way for $value to NOT be an array is if there is a bug in
+        #  the caller such that a scalar ref was passed where a prior call
+        #  had passed a list ref for the same RC option name
+        die("unexpected ARRAY for $key value")
+            if ('ARRAY' eq ref($value));
+        $$r = $value;
+        info(2, "  assign $$r to $key\n");
+    }
+}
+
 #
-# read_config(filename)
-#
-# Read configuration file FILENAME and return a reference to a hash containing
-# all valid key=value pairs found.
+# read_config(filename, $optionsHash)
 #
+# Read configuration file FILENAME and write supported key/values into
+#   RC options hash
+# Return: 1 if some config value was set, 0 if not (used for error messaging)
 
-sub read_config($)
+sub read_config($$);    # forward decl, to make perl happy about recursive call
+my %included_config_files;
+my @include_stack;
+
+sub read_config($$)
 {
-    my $filename = shift;
-    my %result;
+    my ($filename, $opts) = @_;
     my $key;
     my $value;
     local *HANDLE;
 
+    my $set_value = 0;
     info(1, "read_config: $filename\n");
+    if (exists($included_config_files{abs_path($filename)})) {
+        lcovutil::ignorable_error($lcovutil::ERROR_USAGE,
+                                  'config file inclusion loop detected: "' .
+                                      join('" -> "', @include_stack) .
+                                      '" -> "' . $filename . '"');
+        return 0;
+    }
+
     if (!open(HANDLE, "<", $filename)) {
         lcovutil::ignorable_error($lcovutil::ERROR_USAGE,
                               "cannot read configuration file '$filename': $!");
-        return undef;
+        return 0;    # didn't set anything
     }
+    $included_config_files{abs_path($filename)} = 1;
+    push(@include_stack, $filename);
     VAR: while (<HANDLE>) {
         chomp;
         # Skip comments
@@ -1337,15 +1325,15 @@ sub read_config($)
         }
         if (defined($key) && defined($value)) {
             info(2, "  set: $key = $value\n");
-            if (exists($result{$key})) {
-                if ('ARRAY' eq ref($result{$key})) {
-                    push(@{$result{$key}}, $value);
-                } else {
-                    $result{$key} = [$result{$key}, $value];
-                }
-            } else {
-                $result{$key} = $value;
+            # special case: read included file
+            if ($key eq 'config_file') {
+                $set_value |= read_config($value, $opts);
+                next;
             }
+            # skip if application doesn't use this setting
+            next unless exists($opts->{$key});
+            _set_config($opts, $key, $value);
+            $set_value = 1;
         } else {
             my $context = MessageContext::context();
             push(
@@ -1357,7 +1345,9 @@ sub read_config($)
         }
     }
     close(HANDLE) or die("unable to close $filename: $!\n");
-    return \%result;
+    delete $included_config_files{abs_path($filename)};
+    pop(@include_stack);
+    return $set_value;
 }
 
 # common utility used by genhtml, geninfo, lcov to clean up RC options,
@@ -1387,17 +1377,14 @@ sub apply_rc_params($)
 
     if (0 != scalar(@opt_config_files)) {
         foreach my $f (@opt_config_files) {
-            my $cfg = read_config($f);
-            $set_value |= apply_config(\%rcHash, $cfg);
+            $set_value |= read_config($f, \%rcHash);
         }
     } else {
         foreach my $v (['HOME', '.lcovrc'], ['LCOV_HOME', 'etc', 'lcovrc']) {
             next unless exists($ENV{$v->[0]});
             my $f = File::Spec->catfile($ENV{$v->[0]}, splice(@$v, 1));
             if (-r $f) {
-                my $config = read_config($f);
-                # Copy configuration file and --rc values to variables
-                $set_value |= apply_config(\%rcHash, $config);
+                $set_value |= read_config($f, \%rcHash);
                 last;
             }
         }
diff --git a/man/genhtml.1 b/man/genhtml.1
@@ -3231,7 +3231,10 @@ for more details.
 Specify a configuration file to use.
 See man
 .B lcovrc(5)
-for details of the file format and options.
+for details of the file format and options.  Also see the
+.I config_file
+entry in the same man page for details on how to include one config file into
+another.
 
 When this option is specified, neither the system\-wide configuration file
 /etc/lcovrc, nor the per\-user configuration file ~/.lcovrc is read.
diff --git a/man/geninfo.1 b/man/geninfo.1
@@ -572,7 +572,13 @@ libtool, disable this option to prevent problems when capturing coverage data.
 .br
 .RS
 Specify a configuration file to use.
-See the lcovrc man page for details of the file format and options.
+See man
+.B lcovrc(5)
+for details of the file format and options.
+Also see the
+.I config_file
+entry in the same man page for details on how to include one config file into
+another.
 
 When this option is specified, neither the system\-wide configuration file
 /etc/lcovrc, nor the per\-user configuration file ~/.lcovrc is read.
diff --git a/man/lcov.1 b/man/lcov.1
@@ -671,7 +671,10 @@ libtool, disable this option to prevent problems when capturing coverage data.
 Specify a configuration file to use.
 See man
 .B lcovrc(5)
-for details of the file format and options.
+for details of the file format and options.  Also see the
+.I config_file
+entry in the same man page for details on how to include one config file into
+another.
 
 When this option is specified, neither the system\-wide configuration file
 /etc/lcovrc, nor the per\-user configuration file ~/.lcovrc is read.
diff --git a/man/lcovrc.5 b/man/lcovrc.5
@@ -148,7 +148,21 @@ See the OPTIONS section below for details.
 .br
 #
 .br
-
+# include some other config file
+.br
+#   e.g, user-specific options.  Note the environment variable expansion
+.br
+# config_file = $ENV{HOME}/.user_lcovrc
+.br
+#   or project specific - hard-coded from environment variable
+.br
+# config_file = /path/to/myproject/.lcovrc
+.br
+#   or in the current run directory
+.br
+# config_file = $ENV{PWD}/.lcovrc
+.br
+.br
 # External style sheet file
 .br
 #genhtml_css_file = gcov.css
@@ -727,6 +741,44 @@ maximum during parallel processing.
 
 .SH OPTIONS
 
+.BR config_file " ="
+.I filename
+.IP
+
+Include another config file.
+
+Inclusion is equivalent to inserting the text from
+.I filename
+at this point in the current file.  As a result, settings from the included
+file are processed after earlier settings in the current file, but before later settings from the current file.
+As a result:
+
+.BR "Scalar options"
+set earlier in the current file are overridden by settings from the included file, and scalar options from the included file are overridden by later setting in the current file.
+
+.BR "Array options"
+from earlier in the current file appear before setting from the included file, and array options from later in the current file appear after.
+
+Config file inclusion is recursive:  an included config file may include another file - and so on.
+Inclusion loops are not supported and will result in a
+.I usage
+error.
+
+The most common usecase for config file inclusion is so that a site-wide or project-wide options file can include a user-specific or module-specific options file - for example, as
+
+.RS 3
+.IP
+ ...
+.br
+config_file = $ENV{HOME}/.lcovrc_user
+.br
+ ...
+.PP
+.RE
+
+
+.PP
+
 .BR genhtml_css_file " ="
 .I filename
 .IP
diff --git a/tests/gendiffcov/errs/msgtest.sh b/tests/gendiffcov/errs/msgtest.sh
@@ -3,7 +3,7 @@ set +x
 
 source ../../common.tst
 
-rm -f test.cpp *.gcno *.gcda a.out *.info *.log *.json diff.txt
+rm -f test.cpp *.gcno *.gcda a.out *.info *.log *.json diff.txt loop*.rc markers.err*
 rm -rf select criteria annotate empty unused_src scriptErr scriptFixed epoch inconsistent highlight etc mycache cacheFail expect subset context labels
 
 clean_cover
@@ -203,6 +203,30 @@ if [ 0 != $? ] ; then
     fi
 fi
 
+# loop in config file inclusion
+echo "config_file = loop1.rc" > loop1.rc
+echo lcov $LCOV_OPTS --summary initial.info --config-file loop1.rc --ignore usage
+$COVER $LCOV_TOOL $LCOV_OPTS --summary initial.info --config-file loop1.rc --ignore usage 2>&1 | tee err_selfloop.log
+grep "config file inclusion loop" err_selfloop.log
+if [ 0 != $? ] ; then
+    echo "ERROR: missing config file message"
+    if [ 0 == $KEEP_GOING ] ; then
+        exit 1
+    fi
+fi
+
+echo "config_file = loop3.rc" > loop2.rc
+echo 'config_file = $ENV{PWD}/loop2.rc' > loop3.rc
+echo lcov $LCOV_OPTS --summary initial.info --config-file loop2.rc --ignore usage
+$COVER $LCOV_TOOL $LCOV_OPTS --summary initial.info --config-file loop2.rc --ignore usage 2>&1 | tee err_loop.log
+grep "config file inclusion loop" err_loop.log
+if [ 0 != $? ] ; then
+    echo "ERROR: missing config file message"
+    if [ 0 == $KEEP_GOING ] ; then
+        exit 1
+    fi
+fi
+
 
 echo lcov $LCOV_OPTS --capture -d . -o build.info --build-dir $LCOV_HOME
 $COVER $LCOV_TOOL $LCOV_OPTS --capture -d . -o build.info --build-dir $LCOV_HOME 2>&1 | tee build_dir_unused.log
