config: show unset config items with --debug

Summary: Previously there was no way to use the "config" command to see a config entry was %unset. Now, the --debug flag will give positive indication a config is <%unset> (and tell you where it was unset).

Reviewed By: zzl0

Differential Revision: D47012143

fbshipit-source-id: 611eba126fbdd13593aa64dff23ff7e53eca726b

eden/scm/lib/config/model/src/config.rs

@@ -225,7 +225,7 @@ pub struct ValueLocation {
 }
 
 impl ValueSource {
-    /// Return the actual value stored in this config value, or `None` if uset.
+    /// Return the actual value stored in this config value, or `None` if unset.
     pub fn value(&self) -> &Option<Text> {
         &self.value
     }

eden/scm/lib/hgcommands/src/commands/config.rs

@@ -89,8 +89,7 @@ pub fn run(ctx: ReqCtx<ConfigOpts>, repo: &mut OptionalRepo) -> Result<u8> {
     ctx.maybe_start_pager(repo.config())?;
 
     formatter.begin_list()?;
-    let verbose = ctx.global_opts().verbose;
-    let exit_code = show_configs(ctx.opts.args, config, formatter.as_mut(), verbose)?;
+    let exit_code = show_configs(ctx, config, formatter.as_mut())?;
     formatter.end_list()?;
 
     Ok(exit_code)
@@ -100,7 +99,7 @@ struct ConfigItem<'a> {
     source: String,
     section: &'a str,
     key: &'a str,
-    value: String,
+    value: Option<String>,
     single_item: bool,
     builtin: bool,
 }
@@ -114,7 +113,9 @@ impl<'a> Serialize for ConfigItem<'a> {
         let name = format!("{}.{}", self.section, self.key);
         item.serialize_field("name", name.as_str())?;
         item.serialize_field("source", &self.source)?;
+
         item.serialize_field("value", &self.value)?;
+
         item.end()
     }
 }
@@ -125,6 +126,12 @@ impl<'a> Formattable for ConfigItem<'a> {
         options: &FormatOptions,
         writer: &mut dyn formatter::StyleWrite,
     ) -> std::result::Result<(), anyhow::Error> {
+        let value: &str = match &self.value {
+            Some(value) => value.as_ref(),
+            None if options.debug => "<%unset>",
+            _ => return Ok(()),
+        };
+
         let source_section = if options.debug {
             format!("{}: ", self.source)
         } else {
@@ -140,7 +147,7 @@ impl<'a> Formattable for ConfigItem<'a> {
             "{}{}{}\n",
             source_section,
             kv_section,
-            self.value.replace('\n', "\\n")
+            value.replace('\n', "\\n")
         )?;
         Ok(())
     }
@@ -151,6 +158,7 @@ fn get_config_item<'a>(
     section: &'a str,
     key: &'a str,
     single_item: bool,
+    debug: bool,
 ) -> Option<ConfigItem<'a>> {
     let sources_list = config.get_sources(section, key);
     let config_value_source = match sources_list.last() {
@@ -159,12 +167,13 @@ fn get_config_item<'a>(
         }
         Some(s) => s,
     };
-    let value = match config_value_source.value() {
-        None => {
-            return None;
-        }
-        Some(v) => v.to_string(),
-    };
+
+    let value = config_value_source.value();
+
+    // Don't expose %unset unless --debug was specified.
+    if value.is_none() && !debug {
+        return None;
+    }
 
     let builtin = config_value_source.source().starts_with("builtin:");
     let source = config_value_source
@@ -190,24 +199,30 @@ fn get_config_item<'a>(
         source,
         section,
         key,
-        value,
+        value: value.as_ref().map(|v| v.to_string()),
         single_item,
         builtin,
     })
 }
 
 fn show_configs(
-    requested_configs: Vec<String>,
+    ctx: ReqCtx<ConfigOpts>,
     config: &ConfigSet,
     formatter: &mut dyn ListFormatter,
-    verbose: bool,
 ) -> Result<u8> {
-    let requested_items: Vec<_> = requested_configs
+    let verbose = ctx.global_opts().verbose;
+    let debug = ctx.global_opts().debug;
+
+    let requested_items: Vec<_> = ctx
+        .opts
+        .args
         .iter()
         .filter(|a| a.contains('.'))
         .cloned()
         .collect();
-    let requested_sections: BTreeSet<_> = requested_configs
+    let requested_sections: BTreeSet<_> = ctx
+        .opts
+        .args
         .into_iter()
         .filter_map(|a| {
             if !a.contains('.') {
@@ -228,7 +243,7 @@ fn show_configs(
         let item = &requested_items[0];
         let parts: Vec<_> = item.splitn(2, '.').collect();
 
-        if let Some(item) = get_config_item(config, parts[0], parts[1], true) {
+        if let Some(item) = get_config_item(config, parts[0], parts[1], true, debug) {
             formatter.format_item(&item)?;
             return Ok(0);
         }
@@ -253,7 +268,7 @@ fn show_configs(
         let mut keys = config.keys(section);
         keys.sort();
         for key in keys {
-            if let Some(item) = get_config_item(config, section, &key, false) {
+            if let Some(item) = get_config_item(config, section, &key, false, debug) {
                 if empty_selection && item.builtin && !verbose {
                     continue;
                 }

eden/scm/tests/test-config.t

@@ -136,6 +136,24 @@ Test "%unset"
   $ hg showconfig unsettest
   unsettest.set-after-unset=should be set (.hg/hgrc)
 
+  $ hg showconfig unsettest.both
+  [1]
+  $ hg showconfig unsettest.both --debug
+  *: <%unset> (glob)
+
+  $ hg showconfig unsettest.both -Tjson
+  [
+  ]
+  [1]
+  $ hg showconfig unsettest.both -Tjson --debug
+  [
+  {
+    "name": "unsettest.both",
+    "source": "*", (glob)
+    "value": null
+  }
+  ]
+
 Test exit code when no config matches
 
   $ hg config Section.idontexist