i18n: missing translations are reported, never a failure (#2729)

A message a catalog lacks, or translates as an empty string, shows in
English and fails nothing:

- build.rs no longer requires every formats catalog to carry the same
  messages, and tr_format! gets a last arm that formats the English
  source, so a message no catalog has builds.
- Coverage tests (every language translates X) and tests of one
  language's exact wording are gone; the language-switching, layout,
  date, placeholder and user-value tests read the catalog's own value
  instead of a hard-coded translation.
- i18n::tests::translation_gaps_report lists, per language, the plain
  and format messages it lacks and its untranslated What's New lines.
  It always passes; cargo xtask ci
  runs it from the test step's binary after the tests.
- catalogs_load checks that every catalog file is a JSON object of
  strings with each key once; it.json named "Dimensions" twice.

apps/lightcraft/src/native_menu.rs

@@ -456,10 +456,6 @@ mod tests {
             set_language(*language);
             assert!(seen.insert(structure_of(&bar)), "{language:?} shares another language's menu structure key");
         }
-        set_language(Locale::ZhHant);
-        assert_eq!(label_text("File"), "檔案");
-        assert_eq!(label_text("Settings…"), "設定…");
-        assert_eq!(label_text("Quit LightCraft"), "結束 LightCraft");
         set_language(Locale::En);
     }
 

crates/ui-egui/build.rs

@@ -7,9 +7,9 @@
 //! `{:+}`… keep their meaning). The English source is the fallback arm. Adding a language means
 //! adding its file (and its `language_table!` entry); this script picks the file up by name.
 //!
-//! Every catalog must carry the same messages: a `tr_format!` call whose message is in no catalog
+//! A message a language lacks (or translates as an empty string) shows the English source: that
-//! does not compile, so a message missing from one language would otherwise go unnoticed until it
+//! language has no arm for it, and a message no catalog has formats the English source through the
-//! shows English.
+//! macro's last arm. `i18n::tests::translation_gaps_report` lists the gaps per language.
 //!
 //! It also bakes the contributor credits into the binary as static Rust tables (`$OUT_DIR/credits.rs`,
 //! included by `src/credits.rs`; craftrules `standards/contributors.md`): commit stats from
@@ -61,25 +61,14 @@ fn generate() -> Result<String, Box<dyn std::error::Error>> {
         let Some(code) = name.strip_suffix("-formats.json").filter(|code| *code != "en") else { continue };
         println!("cargo:rerun-if-changed=locales/{name}");
         let variant = variant_for(code)?;
-        let messages: BTreeMap<String, String> =
+        let mut messages: BTreeMap<String, String> =
             serde_json::from_str(&fs::read_to_string(&path)?).map_err(|error| format!("locales/{name}: {error}"))?;
+        messages.retain(|_, translated| !translated.is_empty());
         catalogs.push((code.to_string(), variant, messages));
     }
     catalogs.sort_by(|a, b| a.0.cmp(&b.0));
 
-    // Every catalog translates the same messages.
     let all: BTreeSet<&String> = catalogs.iter().flat_map(|(_, _, messages)| messages.keys()).collect();
-    let mut problems = Vec::new();
-    for (code, _, messages) in &catalogs {
-        for key in &all {
-            if !messages.contains_key(*key) {
-                problems.push(format!("locales/{code}-formats.json is missing {key:?}"));
-            }
-        }
-    }
-    if !problems.is_empty() {
-        return Err(problems.join("\n").into());
-    }
 
     let mut source = String::from(concat!(
         "/// Translate a format string, checked by `format!` in every language.\n",
@@ -98,6 +87,9 @@ fn generate() -> Result<String, Box<dyn std::error::Error>> {
         source.push_str(&format!("            _ => format!({en} $(, $($args)*)?),\n        }}\n    }};\n"));
     }
     source.push_str(concat!(
+        "    ($english:literal $(, $($args:tt)*)?) => {\n",
+        "        format!($english $(, $($args)*)?)\n",
+        "    };\n",
         "}\n",
         "\n",
         "// `macro_rules!` is textual: the module re-export is what lets call sites say\n",

crates/ui-egui/locales/it.json

@@ -2344,7 +2344,6 @@
   "Loupe Info 1": "Info lente 1",
   "Loupe Info 2": "Info lente 2",
   "Use Defaults": "Usa predefiniti",
-  "Dimensions": "Dimensioni",
   "Camera & Lens": "Fotocamera e obiettivo",
   "View → View Options chooses the lines Info 1 and Info 2 show.": "Visualizza → Opzioni di visualizzazione sceglie le righe di Info 1 e Info 2."
 }

crates/ui-egui/src/headless.rs

@@ -2495,7 +2495,7 @@ mod tests {
         assert!(!row.cancellable, "{row:?}");
         assert!(h.app.session.activity.cancel(row.id).is_err(), "Photos can't be stopped once asked");
         let current = h.app.export.as_ref().map(|e| e.progress.lock().unwrap().1.clone()).unwrap_or_default();
-        assert_eq!(current, "Wird zu Apple Fotos hinzugefügt…");
+        assert_eq!(current, crate::i18n::Locale::De.tr("Adding to Apple Photos…"));
         // the row says so on the next frame (issue #345)
         h.step();
         let row = h.app.session.activity.list().into_iter().find(|r| r.kind == "export").expect("the export's row");
@@ -4570,9 +4570,6 @@ mod tests {
             assert_eq!(crate::i18n::language(), locale);
             for (mode, key) in [("basic", "Info Overlay: File"), ("exposure", "Info Overlay: Exposure"), ("off", "Info Overlay Off")] {
                 let expected = locale.tr(key);
-                if locale != Locale::En {
-                    assert_ne!(expected, key, "this locale must translate the tested message");
-                }
                 assert_eq!(h.request("ui.key", json!({"key": "i", "cmd": true}), t)["ok"], true);
                 assert_eq!(serde_json::to_value(h.app.ui.info_overlay).unwrap(), json!(mode));
                 assert_eq!(h.app.ui.toast.as_ref().expect("overlay toast").0, expected);

crates/ui-egui/src/lightroom_import.rs

@@ -684,25 +684,17 @@ mod tests {
     }
 
     #[test]
-    fn skipped_images_are_one_line_in_the_ui_language() {
+    fn skipped_images_are_one_line() {
         let value = json!({"report": {"photos": 3, "collections": 0, "warnings": ["w1", "w2"], "skipped": [
             {"image": 7, "reason": "missingFile"},
             {"image": 8, "reason": "missingRoot"},
             {"image": 9, "reason": "masterSkipped"},
         ]}});
-        let details = |locale| {
-            crate::i18n::set_language(locale);
-            let dialog = result_dialog(&value, "done");
         crate::i18n::set_language(crate::i18n::Locale::En);
-            let crate::state::Dialog::LightroomResult { details, .. } = dialog else { panic!("not a Lightroom result") };
+        let crate::state::Dialog::LightroomResult { details: en, .. } = result_dialog(&value, "done") else { panic!("not a Lightroom result") };
-            details
-        };
-        let en = details(crate::i18n::Locale::En);
         assert_eq!(en.len(), 4, "{en:?}");
         assert_eq!(en[1], "3 catalog images were not imported because their records in the catalog are incomplete.");
         assert_eq!(&en[2..], ["w1", "w2"]);
-        let es = details(crate::i18n::Locale::Es);
-        assert_eq!(es[1], "No se importaron 3 imágenes del catálogo porque sus registros en el catálogo están incompletos.");
     }
 
     #[test]

crates/ui-egui/src/panels/grid.rs

@@ -1533,18 +1533,6 @@ mod tests {
         }
     }
 
-    #[test]
-    fn library_context_menu_labels_have_french_translations() {
-        let saved = crate::i18n::language();
-        crate::i18n::set_language(crate::i18n::Locale::Fr);
-        for (label, expected) in
-            [("Pick", "Sélectionnée"), ("Reject", "Rejeter"), ("Group into Stack", "Regrouper en pile"), ("HDR Panorama…", "Panorama HDR…")]
-        {
-            assert_eq!(crate::i18n::tr(label), expected);
-        }
-        crate::i18n::set_language(saved);
-    }
-
     #[test]
     fn square_grid_groups_and_auto_levels() {
         let l = layout(&[1.0; 5], &[(0, 3), (3, 2)], 400.0, 100.0, true);

crates/ui-egui/src/panels/keyword_list.rs

@@ -520,6 +520,35 @@ fn in_tree(tree: &[KeywordNode], path: &str) -> bool {
     tree.iter().any(|n| same(&n.path, path) || (lightcraft_catalog::keywords::is_under(path, &n.path) && in_tree(&n.children, path)))
 }
 
+/// The labels the Keyword List and its dialogs pass to `tr` through variables, out of reach of a
+/// literal search: the translation gaps report (`i18n`) checks them.
+#[cfg(test)]
+pub(crate) const VARIABLE_LABELS: &[&str] = &[
+    "Include on Export",
+    "Export Containing Keywords",
+    "Export Synonyms",
+    "Person",
+    "Merge Keywords",
+    "No keywords yet",
+    "No keywords match",
+    "Add to Selected Photos",
+    "Remove from Selected Photos",
+    "Keywords",
+    "& Containing",
+    "Will Export",
+    "No keywords are exported",
+    "Add to All Selected Photos",
+    "Set name",
+    "Edit Set…",
+    "Edit Keyword Set",
+    "A keyword set needs a name",
+    "Recent Keywords",
+    "Keywords (⌥1–⌥9)",
+    "Save as a new set",
+    "Import Keywords…",
+    "Export Keywords…",
+];
+
 #[cfg(test)]
 mod tests {
     use lightcraft_catalog::{Op, Photo, Source};
@@ -589,45 +618,4 @@ mod tests {
         let (c, ids) = library(&[&["Ärzte", "ÄRZTE"], &[]]);
         assert_eq!(Ticks::of(&c, &ids).tick("ärzte"), Tick::Some);
     }
-
-    /// The labels the Keyword List and its dialogs pass to `tr` through variables (out of reach of
-    /// a literal search) are translated in every language.
-    #[test]
-    fn labels_passed_through_variables_are_translated() {
-        use crate::i18n::Locale;
-        let labels = [
-            "Include on Export",
-            "Export Containing Keywords",
-            "Export Synonyms",
-            "Person",
-            "Merge Keywords",
-            "No keywords yet",
-            "No keywords match",
-            "Add to Selected Photos",
-            "Remove from Selected Photos",
-            "Keywords",
-            "& Containing",
-            "Will Export",
-            "No keywords are exported",
-            "Add to All Selected Photos",
-            "Set name",
-            "Edit Set…",
-            "Edit Keyword Set",
-            "A keyword set needs a name",
-            "Recent Keywords",
-            "Keywords (⌥1–⌥9)",
-            "Save as a new set",
-            "Import Keywords…",
-            "Export Keywords…",
-        ];
-        let dir = std::path::Path::new(env!("CARGO_MANIFEST_DIR")).join("locales");
-        for code in ["de", "es", "fr", "pt-br", "ru", "uk", "it", "ka", "ja", "zh-hans", "zh-hant", "pl", "cs", "sv", "fi", "id", "vi"] {
-            let text = std::fs::read_to_string(dir.join(format!("{code}.json"))).unwrap();
-            let catalog: std::collections::HashMap<String, String> = serde_json::from_str(&text).unwrap();
-            for label in labels {
-                assert!(catalog.contains_key(label), "{code}: “{label}”");
-            }
-        }
-        assert_eq!(Locale::ALL.len(), 18, "a language added: list its file above");
-    }
 }

crates/ui-egui/src/panels/masking.rs

@@ -897,25 +897,6 @@ fn brush_settings(app: &mut LightcraftApp, ui: &mut egui::Ui) {
 mod tests {
     use super::*;
 
-    #[test]
-    fn masking_context_actions_use_catalog_translations() {
-        let saved = crate::i18n::language();
-        crate::i18n::set_language(crate::i18n::Locale::Fr);
-        for (english, translated) in [
-            ("Duplicate Mask", "Dupliquer le masque"),
-            ("Invert Mask", "Inverser le masque"),
-            ("Hide Mask", "Masquer le masque"),
-            ("Move Up", "Monter"),
-            ("Brush", "Pinceau"),
-            ("Luminance Range", "Plage de luminance"),
-        ] {
-            assert_eq!(menu_label(english), translated, "{english}");
-        }
-        // An arbitrary user name has no catalog entry and is left unchanged.
-        assert_eq!(menu_label("My custom mask"), "My custom mask");
-        crate::i18n::set_language(saved);
-    }
-
     /// The grid keeps four 52 pt tiles when the labels fit, and gives a long (translated) label
     /// room by dropping a column rather than drawing it past its tile.
     #[test]

crates/ui-egui/src/tests_album_picker.rs

@@ -343,20 +343,12 @@ mod import_review {
         }
     }
 
-    /// Every shipped locale paints translated destination choices and initializes a translated new name.
+    /// Every shipped locale paints its own destination choices and names a new album in its language.
     #[test]
     fn import_album_picker_localizes_choices_in_every_shipped_language() {
         use crate::i18n::Locale;
         let Review { mut h, .. } = review();
         for locale in Locale::ALL {
-            for source in
-                ["None", "New album", "New album…", "Imported Photos", "Choose an album…", "Search albums", "No albums yet", "No albums match"]
-            {
-                assert!(!locale.tr(source).is_empty());
-                if *locale != Locale::En {
-                    assert_ne!(locale.tr(source), source, "{locale:?}: {source}");
-                }
-            }
             let r = h.request("ui.set", json!({"language": locale.code()}), T);
             assert_eq!(r["ok"], true, "{r}");
             assert!(h.settle(SETTLE));

docs/localization-cs.md

@@ -46,8 +46,9 @@ ani anglické zdrojové řetězce. Rozložení panelů a seznamu jazyků je beze
 ## Ověření a revize
 
 Testy `i18n::tests` ověřují registraci příkazu, přepínání přes nabídku a řídicí kanál,
-uložení jazyka, pokrytí katalogů, placeholdery, neutrální formulace počtů, datum, čas
+uložení jazyka, placeholdery, datum, čas a české glyfy. Překladové šablony kontroluje také
-a české glyfy. Překladové šablony kontroluje také Rust při sestavení.
+Rust při sestavení. Chybějící překlady se zobrazují anglicky a vypisuje je
+`i18n::tests::translation_gaps_report`; žádný test kvůli nim neselže.
 
 Při jazykové korektuře doporučujeme zkontrolovat „asistované třídění“, „sada“ pro Stack,
 „bodová barva“, „měkký nátisk“ a názvy kreativních přednastavení.

docs/localization-de.md

@@ -29,8 +29,8 @@ cargo test -p lightcraft-ui-egui i18n::tests
 LIGHTCRAFT_LANGUAGE=de lightcraft-cli snapshot --demo -o deutsch.png --size 1600x1000
 ```
 
-Die Tests prüfen Katalogabdeckung, Platzhalter, Sprachwechsel per Menü und Steuerkanal,
+Die Tests prüfen Platzhalter, Sprachwechsel per Menü und Steuerkanal, Speicherung,
-Speicherung, Datumsformate, unveränderte Benutzernamen und gerenderte Texte sowie Umlaute
+Datumsformate, unveränderte Benutzernamen und gerenderte Texte sowie Umlaute und ß. Fehlende
-und ß. Ein weiterer Render-Test prüft die Schaltflächenbreiten; der Importtest prüft
+Übersetzungen erscheinen auf Englisch; `i18n::tests::translation_gaps_report` listet sie auf. Ein weiterer Render-Test prüft die Schaltflächenbreiten; der Importtest prüft
 auch den Sprachwechsel nach der Hintergrundprüfung der Quellen. Akzeptierte Sprachangaben umfassen `de`, `de-DE`, `de_AT.UTF-8` und `de-CH`;
 gespeichert wird stets `de`. Weitere Hinweise stehen in [localization.md](localization.md).

docs/localization-fi.md

@@ -52,8 +52,9 @@ englanniksi. Käännös ei muuta kirjastotietoja eikä englanninkielisiä lähde
 ## Testaus
 
 `i18n::tests` tarkistaa komennon rekisteröinnin, vaihdon valikosta ja ohjauskanavasta,
-kielen tallennuksen, luetteloiden kattavuuden, paikkamerkit, määrämuodot, päivämäärän, ajan ja
+kielen tallennuksen, paikkamerkit, päivämäärän, ajan ja suomen kirjaimet. Rust tarkistaa
-suomen kirjaimet. Rust tarkistaa muotoilumallit käännösvaiheessa.
+muotoilumallit käännösvaiheessa. Puuttuvat käännökset näkyvät englanniksi, ja
+`i18n::tests::translation_gaps_report` luettelee ne; mikään testi ei epäonnistu niiden takia.
 
 Kielentarkistuksessa kannattaa katsoa erityisesti: ”Väriluokittelu” (Color Grading),
 ”Valoalueet / Valkoiset” (Highlights / Whites), ”Näyttövedos” (Soft Proofing),

docs/localization-ka.md

@@ -19,7 +19,7 @@ not translated. Descriptions for SAM 3 go to the model unchanged.
 ## Georgian script
 
 Mkhedruli has no upper and lower case: `i18n::upper_first` leaves Georgian letters alone, and the
-interface never uses Mtavruli (a test checks the whole catalog). Commands are verbal nouns. Counts
+interface never uses Mtavruli. Commands are verbal nouns. Counts
 are count-neutral, noun first (`იმპორტირებულია ფოტო: 3`); English plural endings are dropped with
 `{:.0}`. Dates read `კვირა, 20.09.2026` (`{weekday}, {day:02}.{month:02}.{year}`), months `09.2026`.
 
@@ -73,7 +73,7 @@ cargo test -p lightcraft-ui-egui i18n::tests -- --nocapture
 LIGHTCRAFT_LANGUAGE=ka lightcraft-cli snapshot --demo -o georgian.png --size 1600x1000
 ```
 
-The tests check catalog coverage, placeholders, switching language by menu and control channel,
+The tests check placeholders, switching language by menu and control channel, saving, the `ka`
-saving, the `ka` locale tags, dates, count wording, the absence of Mtavruli and that sentence case
+locale tags, dates and that sentence case keeps Georgian lowercase. Messages Georgian lacks show in
-keeps Georgian lowercase. More notes are in
+English; `i18n::tests::translation_gaps_report` lists them. More notes are in
 [localization.md](localization.md).

docs/localization-vi.md

@@ -66,8 +66,9 @@ LIGHTCRAFT_LANGUAGE=vi lightcraft-cli snapshot --demo -o vi.png --size 1600x1000
 LIGHTCRAFT_LANGUAGE=vi lightcraft-cli snapshot --demo -o vi-narrow.png --size 1280x800
 ```
 
-Các test tiếng Việt bắt buộc phủ catalog union, nhãn lệnh/control/Settings/Smart Album,
+Các test tiếng Việt kiểm tra đổi ngôn ngữ, lưu `vi`, formats, ngày, dữ liệu người dùng và glyph
-đổi ngôn ngữ, lưu `vi`, formats, ngày, dữ liệu người dùng, và glyph dấu.
+dấu. Chuỗi còn thiếu hiện bằng tiếng Anh và được `i18n::tests::translation_gaps_report` liệt kê;
+không test nào thất bại vì thiếu bản dịch.
 
 ## Nguồn dịch (clean-room)
 

docs/localization-zh-hans.md

@@ -34,5 +34,6 @@ LightCraft 的界面支持英语、简体中文、繁体中文（台湾）和日
 
 `LIGHTCRAFT_LANGUAGE=zh-hans lightcraft-cli snapshot ...` 可以渲染中文界面用于检查。
 
-翻译是否完整、两种目录的键与占位符是否一致、字形是否齐全，都由
+两种目录的占位符是否一致、字形是否齐全，由
 `cargo test -p lightcraft-ui-egui i18n::tests` 验证（字形检查只在指定 `CRAFT_FONTS_DIR` 时实际执行）。
+缺少的译文显示为英文，由 `i18n::tests::translation_gaps_report` 列出，不会让测试失败。

docs/localization.md

@@ -12,11 +12,10 @@ are in [`localization-zh-hans.md`](localization-zh-hans.md), [`localization-zh-h
 
 1. **Translate the two catalogs.** Copy `locales/ja.json` and `locales/ja-formats.json` to
    `locales/<code>.json` and `locales/<code>-formats.json`, then translate the values. Keys are the
-   English source strings and must stay byte-for-byte identical. The plain catalog may grow at its
+   English source strings and must stay byte-for-byte identical. Both catalogs may grow at their
-   own pace: a message it lacks shows in English, and `cargo test -p lightcraft-ui-egui i18n::tests
+   own pace: a message a catalog lacks, or translates as an empty string, shows in English, and
-   -- --nocapture` lists the gaps (it fails on an empty entry or mismatched placeholders). The
+   nothing fails. The translation gaps report lists what each language lacks (see
-   formats catalog must carry every message (the build fails otherwise; a message copied in English,
+   [Testing and looking at it](#testing-and-looking-at-it)). The formats catalog also holds the date
-   value equal to its key, is an untranslated placeholder until someone translates it), including the date
    patterns (`{year}`, `{month} {year}`, `{weekday}, {day} {month} {year}`…) that date headings and
    capture times use in every language but English; weekday names go in the plain catalog.
 2. **Add the table entry** in `crates/ui-egui/src/i18n.rs`:
@@ -81,18 +80,23 @@ tr_format!("Added {n} photo{} to “{}”", if n == 1 { "" } else { "s" }, album
   `"已将 {n} 张照片添加到“{1}”{0:.0}"`. Keep the source's spec (`{:.1}`, `{d:+}`, `{:.0}%`).
 - `format!` rejects an unused argument, so a value a language does not need — the English plural
   suffix (`"s"` / `""`) — is consumed as `{:.0}` (a string at precision 0 prints nothing).
-- Every formats catalog carries the same messages (`build.rs` fails the build otherwise), and a
+- A language whose formats catalog lacks a message shows the English source there, and a
-  `tr_format!` call whose message is in no catalog does not compile: add it to every
+  `tr_format!` call whose message is in no catalog formats the English source (the macro's last
-  `*-formats.json` file.
+  arm). A new message builds with no catalog entry.
 
 ## Testing and looking at it
 
 ```sh
-cargo test -p lightcraft-ui-egui i18n::tests                       # catalogs, keys, placeholders, commands
+cargo test -p lightcraft-ui-egui i18n::tests                       # catalogs load, placeholders, switching
 CRAFT_FONTS_DIR=../craft-fonts cargo test -p lightcraft-ui-egui i18n::tests   # + glyph coverage
+cargo test -p lightcraft-ui-egui --lib -- --exact i18n::tests::translation_gaps_report --nocapture
 ```
 
-The glyph tests are skipped without `CRAFT_FONTS_DIR` (there are no CJK faces to check then).
+The tests fail on a broken catalog (malformed JSON, a repeated key, placeholders that differ from
+the source), never on a missing translation. The last command is the translation gaps report: per
+language, the count and list of plain and format messages it lacks and the number of untranslated
+What's New lines. It always passes, and `cargo xtask ci` prints it after its test step. The glyph
+tests are skipped without `CRAFT_FONTS_DIR` (there are no CJK faces to check then).
 To look at a language, render it headless:
 
 ```sh
@@ -114,5 +118,5 @@ when a region has no dedicated entry.
 Help ▸ What's New shows `docs/whats-new.md`, and each of its lines (a heading, or one wrapped line of a
 bullet, without the `- ` or `### `) is looked up like any message, so a catalog can translate the notes
 line by line (German does). A line that is re-wrapped or edited no longer matches its translation and
-shows in English until the catalog is updated; untranslated lines are reported by
+shows in English until the catalog is updated; the translation gaps report counts the untranslated
-`display_label_gaps_are_reported`, never failed.
+lines.

xtask/src/main.rs

@@ -37,7 +37,8 @@ commands:
   ci [--hardware] [--summary-md]
                   fmt --check, clippy -D warnings, heif, test, GPU probe, parity refs, layers, assets, wasm
                   (stops at first failure). Tests run under cargo test (cargo nextest with
-                  LIGHTCRAFT_NEXTEST=1), without examples, then doctests with cargo test --doc. Writes
+                  LIGHTCRAFT_NEXTEST=1), without examples, then doctests with cargo test --doc; after
+                  them it prints the translation gaps report (never a failure). Writes
                   target/ci/report.json (machine, GPU adapters, data,
                   steps, skipped tests) and target/ci/summary.md; --hardware also runs the GPU tests on
                   every backend with a hardware adapter; --summary-md prints the Markdown summary
@@ -238,6 +239,39 @@ fn doctests() -> (Command, String) {
     (c, "cargo test --workspace --doc".to_owned())
 }
 
+/// The test that prints the messages each language lacks (shown in English); it always passes.
+const TRANSLATION_GAPS_TEST: &str = "i18n::tests::translation_gaps_report";
+
+/// Print the translation gaps report into the log: [`TRANSLATION_GAPS_TEST`] of lightcraft-ui-egui,
+/// run from the test binary the test step built (found with `--no-run` and the step's own
+/// arguments, so nothing rebuilds). A report that can't run is a note, never a failed step.
+fn translation_gaps() {
+    eprintln!("\n=== ci: translation gaps ===");
+    let mut c = cargo();
+    c.args(["test", "--no-run", "--message-format=json"]).args(with_test_targets(&["--workspace"]));
+    let binary = c.output().map_err(|e| format!("cargo test --no-run: {e}")).and_then(|out| {
+        String::from_utf8_lossy(&out.stdout)
+            .lines()
+            .filter_map(|line| serde_json::from_str::<serde_json::Value>(line).ok())
+            .find(|m| {
+                m["reason"] == "compiler-artifact"
+                    && m["target"]["name"] == "lightcraft_ui_egui"
+                    && m["profile"]["test"] == true
+                    && m["target"]["kind"].as_array().is_some_and(|kinds| kinds.iter().any(|kind| kind == "lib"))
+            })
+            .and_then(|m| m["executable"].as_str().map(PathBuf::from))
+            .ok_or_else(|| format!("no lightcraft-ui-egui test binary in the build (cargo exited with {})", out.status))
+    });
+    let ran = binary.and_then(|binary| {
+        let mut c = Command::new(&binary);
+        c.args(["--exact", TRANSLATION_GAPS_TEST, "--nocapture", "--quiet"]);
+        run(c, &format!("{} --exact {TRANSLATION_GAPS_TEST} --nocapture --quiet", binary.display()))
+    });
+    if let Err(e) = ran {
+        eprintln!("note: the translation gaps report did not run: {e}");
+    }
+}
+
 pub fn run(mut cmd: Command, what: &str) -> Result<(), String> {
     eprintln!("$ {what}");
     let status = cmd.status().map_err(|e| format!("{what}: failed to spawn: {e}"))?;
@@ -431,6 +465,7 @@ fn cmd_ci(args: &[&str]) -> Result<(), String> {
         if *name == "test" {
             // right after the workspace tests, before parity and wasm build other feature sets
             probe();
+            translation_gaps();
         }
         if let Err(e) = r {
             failure = Some((*name, e));