Output default values for plugin config fields from plz query config

Author: marcuscaisey

.gitignore

@@ -9,6 +9,7 @@
 __pycache__
 
 .idea
+.vscode
 *.iml
 /venv
 /out

src/query/BUILD

@@ -14,6 +14,7 @@ go_library(
         "//src/core",
         "//src/fs",
         "//src/parse",
+        "//src/plz",
     ],
 )
 

src/query/config.go

@@ -9,6 +9,7 @@ import (
 	"github.com/please-build/gcfg"
 
 	"github.com/thought-machine/please/src/core"
+	"github.com/thought-machine/please/src/plz"
 )
 
 // Config prints configuration settings in human-readable format.
@@ -29,7 +30,15 @@ func Config(config *core.Configuration, options []string) {
 
 			values, err := gcfg.Get(config, section, subsection, name)
 			if err != nil {
-				log.Fatalf("Failed to get %s: %s", option, err)
+				if section == "plugin" {
+					if defaultValues, ok := pluginConfigFieldDefaultValues(config, subsection, name); ok {
+						values = defaultValues
+						err = nil
+					}
+				}
+				if err != nil {
+					log.Fatalf("Failed to get %s: %s", option, err)
+				}
 			}
 
 			for _, value := range values {
@@ -39,6 +48,53 @@ func Config(config *core.Configuration, options []string) {
 	}
 }
 
+// pluginConfigFieldDefaultValues returns the default values of a plugin config field and a boolean indicating whether
+// the plugin field actually exists.
+func pluginConfigFieldDefaultValues(config *core.Configuration, pluginName string, name string) ([]string, bool) {
+	plugin, ok := config.Plugin[pluginName]
+	if !ok {
+		return nil, false
+	}
+
+	state := core.NewBuildState(config)
+	plz.Run([]core.BuildLabel{plugin.Target}, nil, state, state.Config, state.TargetArch)
+	subrepo := state.Graph.SubrepoOrDie(pluginName)
+	subrepo.State.Initialise(subrepo)
+
+	for key, field := range subrepo.State.RepoConfig.PluginConfig {
+		configKey := field.ConfigKey
+		if configKey == "" {
+			configKey = strings.ReplaceAll(key, "_", "")
+		}
+		if strings.EqualFold(configKey, name) {
+			values := normaliseBuildLabels(field.DefaultValue, subrepo.Name)
+			return values, true
+		}
+	}
+
+	return nil, false
+}
+
+// normaliseBuildLabels returns a copy of values with each build label made absolute.
+// For example, //tools/bar in subrepo foo is replaced by ///foo//tools/bar.
+func normaliseBuildLabels(values []string, subrepo string) []string {
+	valuesCopy := make([]string, len(values))
+	for i, value := range values {
+		if core.LooksLikeABuildLabel(value) {
+			target, annotation := core.SplitLabelAnnotation(value)
+			if label, err := core.TryParseBuildLabel(target, "", subrepo); err == nil {
+				annotatedLabel := core.AnnotatedOutputLabel{
+					BuildLabel: label,
+					Annotation: annotation,
+				}
+				value = annotatedLabel.String()
+			}
+		}
+		valuesCopy[i] = value
+	}
+	return valuesCopy
+}
+
 // ConfigJSON prints the configuration settings as JSON.
 func ConfigJSON(config *core.Configuration) {
 	data, err := gcfg.RawJSON(config)

test/plz_query/config/BUILD

@@ -17,6 +17,27 @@ BUILD.plz
 60000000000""",
 )
 
+please_repo_e2e_test(
+    name = "plugin_config_field_default_value",
+    repo = "test_repo",
+    data = {"plugin": [":foo_plugin"]},
+    plz_command = "plz -o please.pluginrepo:file://$TMP_DIR/$DATA_PLUGIN query config plugin.foo.fooctool plugin.foo.bartools > output.txt",
+    expected_output = {"output.txt": """fooc
+///foo//tools/bar:bar
+///baz//tools/bar:bar
+"""},
+)
+
+genrule(
+    name = "foo_plugin",
+    srcs = {
+        "plugin": ["foo_plugin"],
+        "tool": ["//test/plugins/tools:fooc"],
+    },
+    outs = ["foo_plugin.tar.gz"],
+    cmd = "mv $SRCS_PLUGIN foo_plugin && mv $SRCS_TOOL foo_plugin/tools && tar -czf $OUT foo_plugin",
+)
+
 plz_e2e_test(
     name = "json_config",
     cmd = "plz query config --json",

test/plz_query/config/foo_plugin/.plzconfig

@@ -0,0 +1,10 @@
+[PluginDefinition]
+name = foo
+
+[PluginConfig "fooc_tool"]
+DefaultValue = fooc
+
+[PluginConfig "bar_tools"]
+Repeatable = true
+DefaultValue = //tools/bar
+DefaultValue = ///baz//tools/bar

test/plz_query/config/test_repo/.plzconfig

@@ -0,0 +1,2 @@
+[Plugin "foo"]
+Target = //:foo

test/plz_query/config/test_repo/BUILD_FILE

@@ -0,0 +1,4 @@
+plugin_repo(
+    name = "foo",
+    revision = "v1.0.0",
+)