fix(scripts): report only what generation changed, not the worktree

The codegen-check hook was `go generate` followed by a bare
`git diff --name-only`, which is the whole unstaged worktree rather than
the generators' output. So a commit whose staged changes were fine failed
whenever anything unrelated sat unstaged — notes, a plan document, the
next commit's files — reporting "Generated code is out of date" and then
a diffstat of files no generator has ever written. `make generate` fixed
nothing, because nothing was stale, so the message sent you looking for a
codegen problem that did not exist. Splitting one piece of work into
several commits is exactly the shape that triggers it.

The tree is snapshotted either side of `go generate` and only what moved
across it is reported. That is deliberately a snapshot rather than the
list of generated paths the issue offers as the other option: a fourth
generator is one //go:generate line away, and a path list is a second
place to remember it.

Two things it has to get right. The comparison is a *symmetric*
difference, because generation can push a file into the unstaged set or
pull it out of one — a hand-edited generated file that the generator puts
back is stale generated code just as much as a source change that
outdates it, and comparing one direction reports it as current. And the
snapshot is content, not names, or a generated file that was already
dirty and is then rewritten further keeps its name on both sides and
slips through.

Closes #131

frontend/src/components/now-playing/now-playing.ts

@@ -13,7 +13,6 @@ import {
     isQueueSourceNavigable,
     navigateToQueueSource,
 } from '@utils/queue-source-link';
-import { PHONE_QUERY } from '@utils/breakpoints';
 import { PlayerController } from '@store/controllers/player-controller';
 import { creditStore } from '@store/credit-store';
 import { QueueController } from '@store/controllers/queue-controller';
@@ -81,19 +80,6 @@ export class NowPlaying extends LitElement {
 
     private reduceMotionQuery?: MediaQueryList;
 
-    /**
-     * Phone width, from the shell's own breakpoint.
-     *
-     * This is in JS rather than in the stylesheet because what changes
-     * is the *content*, not its appearance: the title, artist and
-     * source render as plain text instead of as links, and no CSS rule
-     * can take a click handler off an element.
-     */
-    @state()
-    private phone = false;
-
-    private phoneQuery?: MediaQueryList;
-
     /** Whether each field is actively mid-scroll (class toggle). */
     @state()
     private titleScrolling = false;
@@ -355,12 +341,6 @@ export class NowPlaying extends LitElement {
         this.reduceMotion = this.reduceMotionQuery?.matches ?? false;
         this.reduceMotionQuery?.addEventListener('change', this.handleReduceMotionChange);
 
-        // Same reasoning as above: looked up here, not at module load,
-        // so a test can install its own matchMedia first.
-        this.phoneQuery = window.matchMedia?.(PHONE_QUERY);
-        this.phone = this.phoneQuery?.matches ?? false;
-        this.phoneQuery?.addEventListener('change', this.handlePhoneChange);
-
         this.resizeObserver = new ResizeObserver(() => {
             this.geometryDirty = true;
             this.requestUpdate();
@@ -384,7 +364,6 @@ export class NowPlaying extends LitElement {
         this.attachDragListeners(false);
         window.removeEventListener(SCROLL_CHANGE_EVENT, this.handleScrollModeEvent);
         this.reduceMotionQuery?.removeEventListener('change', this.handleReduceMotionChange);
-        this.phoneQuery?.removeEventListener('change', this.handlePhoneChange);
         this.resizeObserver?.disconnect();
         this.stopScrollCycle('title');
         this.stopScrollCycle('artist');
@@ -509,7 +488,7 @@ export class NowPlaying extends LitElement {
               @mouseleave=${this.handleTitleMouseLeave}
               @transitionend=${() => this.onScrollCycleEnd('title')}
             >
-              <span class="scroll-content">${this.phone ? track.title : trackLink(track.title, track.album, track.releaseGroupMbid, track.recordingMbid) || track.title}</span>
+              <span class="scroll-content">${trackLink(track.title, track.album, track.releaseGroupMbid, track.recordingMbid) || track.title}</span>
             </span>
             <span
               class="track-artist ${artistScrolling ? 'will-scroll' : ''} ${this.artistScrolling ? 'scrolling' : ''}"
@@ -519,15 +498,14 @@ export class NowPlaying extends LitElement {
               @mouseleave=${this.handleArtistMouseLeave}
               @transitionend=${() => this.onScrollCycleEnd('artist')}
             >
-              <span class="scroll-content">${this.phone ? track.artist || 'Unknown Artist' : creditLink(creditStore.credits(track.recordingMbid), track.artist, track.artistMbid) || 'Unknown Artist'}</span>
+              <span class="scroll-content">${creditLink(creditStore.credits(track.recordingMbid), track.artist, track.artistMbid) || 'Unknown Artist'}</span>
             </span>
             ${describeQueueSource(this.queue.source)
                 ? html`
                   <span
-                    class="track-source ${!this.phone && isQueueSourceNavigable(this.queue.source) ? 'navigable' : ''}"
+                    class="track-source ${isQueueSourceNavigable(this.queue.source) ? 'navigable' : ''}"
                     data-testid="now-playing-source"
                     @click=${(e: MouseEvent) => {
-                        if (this.phone) return;
                         if (!isQueueSourceNavigable(this.queue.source)) return;
                         navigateToQueueSource(
                             e.currentTarget as EventTarget,
@@ -593,10 +571,6 @@ export class NowPlaying extends LitElement {
         this.reduceMotion = e.matches;
     };
 
-    private handlePhoneChange = (e: MediaQueryListEvent): void => {
-        this.phone = e.matches;
-    };
-
     private shouldScroll(field: 'title' | 'artist'): boolean {
         const overflows = field === 'title' ? this.titleOverflows : this.artistOverflows;
 
@@ -632,12 +606,6 @@ export class NowPlaying extends LitElement {
             track?.artist ?? '',
             this.shouldScroll('title') ? '1' : '0',
             this.shouldScroll('artist') ? '1' : '0',
-            // Crossing the breakpoint swaps a link for a bare string,
-            // and a link is not guaranteed to measure the same as the
-            // text inside it. The marquee travels a distance read from
-            // that measurement, so this belongs in the key even though
-            // the words are identical either side.
-            this.phone ? '1' : '0',
         ].join('\u0000');
     }
 

frontend/src/components/track-list/track-list.ts

@@ -11,7 +11,6 @@ import {
 import { SelectionController } from '@utils/selection-controller';
 import type { SelectionHost } from '@utils/selection-controller';
 import { ViewLifecycleMixin } from '@utils/view-lifecycle';
-import { PHONE_QUERY } from '@utils/breakpoints';
 import {
     ContextMenuController,
     contextMenuStyles,
@@ -106,6 +105,9 @@ const ROW_CHROME_WIDTH =
 const ROW_HEIGHT = 33;
 const PHONE_ROW_HEIGHT = 52;
 
+/** The shell's phone breakpoint, as `index.css` and every component
+ *  stylesheet spells it. */
+const PHONE_QUERY = '(max-width: 599px)';
 
 // Inline SVG paths for favorite icons — eliminates wa-icon shadow DOM
 // overhead (30-50 shadow roots during scroll).  Font Awesome 6 paths.

frontend/src/utils/breakpoints.ts

@@ -1,23 +0,0 @@
-/**
- * The shell's breakpoints, where JavaScript has to agree with CSS.
- *
- * A media query inside a shadow root is answered by the viewport, so a
- * component normally states what it drops at phone width in its own
- * stylesheet and needs nothing from here. This exists for the cases
- * where the decision is not a style: `track-list` computes its grid in
- * JS from the host width, and `now-playing` renders *different content*
- * on a phone — a plain string instead of a link — which no stylesheet
- * can express.
- *
- * One breakpoint, several expressions of it. It was a private const in
- * track-list.ts when there was one; a second reader is where a copy
- * would start drifting from index.css.
- */
-
-/**
- * Phone width. 600px rather than the sidebar's 900px because 900 is a
- * laptop: the answer there is a narrower sidebar, which is still a
- * sidebar. Below this the shell drops the sidebar column entirely and
- * bottom-nav takes over.
- */
-export const PHONE_QUERY = '(max-width: 599px)';

frontend/test/components/now-playing-phone.test.ts

@@ -1,166 +0,0 @@
-/**
- * The mini player's links are a desktop affordance.
- *
- * `utils/explore-link.ts` makes every track and artist name navigate,
- * and `utils/queue-source-link.ts` makes "Playing from X" navigate — in
- * the bottom bar those are a few characters of text at a font size
- * chosen for a bar, which is not a touch target. Worse, explore-link
- * holds the navigation for one double-click interval and drops it if a
- * second click arrives: a gesture that exists so double-clicking a row
- * can play it, and which means nothing at all on touch.
- *
- * So below the shell's phone breakpoint the three render as plain text
- * and the whole bar's cover art opens the full-screen Now Playing view,
- * which is where the links live.
- *
- * The breakpoint is stubbed rather than emulated for the reason
- * track-list-phone.test.ts states: this tier's viewport is fixed at
- * 1280x800 by the runner, and the component reads matchMedia in
- * connectedCallback precisely so a test can answer it first.
- */
-import { describe, expect, it, beforeEach } from 'vitest';
-
-import '@components/now-playing/now-playing';
-import { Events } from '../../src/events';
-import { emit, flush } from '@test/support/harness';
-import { fixture, shadow, shadowAll, text } from '@test/support/render';
-import type { TrackInfo } from '@store/player-store';
-import type { QueueTrack } from '@store/queue-store';
-
-const TRACK: TrackInfo = {
-  fileName: 'ashes.mp3',
-  filePath: '/music/ashes.mp3',
-  trackLength: 215,
-  seekPosition: 0,
-  state: 'playing',
-  title: 'Ashes to Ashes',
-  artist: 'David Bowie',
-  album: 'Scary Monsters',
-  coverArt: '',
-  coverArtSmall: '',
-  coverArtMedium: '',
-  coverArtLarge: '',
-  trackChangeId: 1,
-  artistMbid: '',
-  releaseGroupMbid: '',
-  recordingMbid: '',
-};
-
-function queueTrack(n: number, title: string): QueueTrack {
-  return {
-    id: n,
-    audioFileId: n,
-    filePath: `/music/${n}.mp3`,
-    position: n,
-    title,
-    artist: 'David Bowie',
-    album: 'Scary Monsters',
-    coverArtPath: '',
-    artistMbid: '',
-    releaseGroupMbid: '',
-    recordingMbid: '',
-  };
-}
-
-/** Mount the bar with the phone breakpoint answering `matches`. */
-async function mountAt(phone: boolean) {
-  const real = window.matchMedia.bind(window);
-
-  window.matchMedia = ((q: string) =>
-    q.includes('max-width: 599px')
-      ? {
-          matches: phone,
-          media: q,
-          addEventListener() {},
-          removeEventListener() {},
-        }
-      : real(q)) as typeof window.matchMedia;
-
-  try {
-    const el = await fixture('now-playing');
-
-    emit(Events.TrackChanged, { ...TRACK, trackChangeId: 20 });
-    emit(Events.QueueChanged, {
-      tracks: [queueTrack(1, 'Ashes to Ashes')],
-      currentIndex: 0,
-      source: { type: 'album', id: 7, label: 'Scary Monsters' },
-    });
-    await flush();
-    await el.updateComplete;
-
-    return el;
-  } finally {
-    window.matchMedia = real;
-  }
-}
-
-describe('the mini player on a phone', () => {
-  beforeEach(() => {
-    emit(Events.TrackChanged, { ...TRACK, trackChangeId: 1 });
-  });
-
-  it('renders the title and artist as plain text', async () => {
-    const el = await mountAt(true);
-
-    expect(shadowAll(el, '.explore-link').length).toBe(0);
-
-    // The words are unchanged — this is about what they are, not about
-    // hiding them. A fix that dropped the text would pass an assertion
-    // about links alone.
-    expect(text(el, '[data-testid="now-playing-title"]')).toContain(
-      'Ashes to Ashes',
-    );
-    expect(text(el, '[data-testid="now-playing-artist"]')).toContain(
-      'David Bowie',
-    );
-  });
-
-  it('does not navigate from the source line', async () => {
-    const el = await mountAt(true);
-    const source = shadow<HTMLElement>(el, '[data-testid="now-playing-source"]');
-
-    expect(source?.classList.contains('navigable')).toBe(false);
-
-    let navigated = false;
-    el.addEventListener('navigate', () => {
-      navigated = true;
-    });
-
-    source?.click();
-
-    expect(navigated).toBe(false);
-  });
-
-  it('still says where the queue came from', async () => {
-    const el = await mountAt(true);
-
-    // Dropping the *link* is the change; dropping the information would
-    // be a different and worse one.
-    expect(text(el, '[data-testid="now-playing-source"]')).toBe(
-      'Playing from Scary Monsters',
-    );
-  });
-
-  it('leaves the desktop bar exactly as it was', async () => {
-    const el = await mountAt(false);
-
-    expect(shadowAll(el, '.explore-link').length).toBeGreaterThan(0);
-
-    const source = shadow<HTMLElement>(el, '[data-testid="now-playing-source"]');
-
-    expect(source?.classList.contains('navigable')).toBe(true);
-
-    let detail: unknown;
-    el.addEventListener('navigate', (e) => {
-      detail = (e as CustomEvent).detail;
-    });
-
-    source?.click();
-
-    expect(detail).toEqual({
-      view: 'explore-album-details',
-      localAlbumId: 7,
-      albumName: 'Scary Monsters',
-    });
-  });
-});

lefthook.yml

@@ -20,19 +20,14 @@ pre-commit:
       glob: "*.go"
       run: go tool golangci-lint run --timeout 5m ./...
 
+    # Snapshots the tree either side of the generators and reports only
+    # what moved across them.  This used to be `go generate` plus a bare
+    # `git diff --name-only`, which is the *whole unstaged worktree* — so
+    # any unrelated edit sitting there was reported as stale generated
+    # code, and `make generate` then fixed nothing.  See the script.
     codegen-check:
       glob: "*.{go,sql,templ}"
-      run: |
+      run: ./scripts/codegen-check.sh
-        go generate ./...
-        if [ -n "$(git diff --name-only)" ]; then
-          echo "Generated code is out of date. Run 'make generate' and stage the changes."
-          # --no-pager, or this blocks forever on `less` waiting for a
-          # keypress that a hook run without a tty will never get: the
-          # commit hangs at exactly the moment it is trying to tell you
-          # why it failed.
-          git --no-pager diff --stat
-          exit 1
-        fi
 
     # frontend/bindings is generated by `wails3`, not `go generate`, so
     # the check above does not cover it.  ~3.5s warm, ~20s on a cold

scripts/codegen-check.sh

@@ -0,0 +1,81 @@
+#!/usr/bin/env bash
+#
+# Fails when `go generate ./...` would change something that is not staged.
+#
+# The obvious spelling of this is `go generate && git diff --name-only`,
+# which is what the hook used to be, and it answers the wrong question:
+# that diff is the *whole unstaged worktree*, so any unrelated edit — a
+# note, a plan document, the next commit's files sitting there while this
+# one lands — was reported as
+#
+#     Generated code is out of date. Run 'make generate' and stage the changes.
+#
+# Running `make generate` then does nothing, because nothing generated is
+# stale, and the message sends you looking for a codegen problem that does
+# not exist.  Splitting one piece of work into several commits is exactly
+# the shape that triggers it, so the workaround was a constraint on commit
+# order for no real reason.
+#
+# So the tree is snapshotted either side of the generators and only what
+# *moved across them* is reported.  That is deliberately not a list of
+# generated paths: sqlcgen, `*_templ.go` and `frontend/src/events.ts` are
+# today's answer, a fourth generator is one `//go:generate` line away, and
+# a path list is a second place to remember it — the same reasoning that
+# keeps staleshape.go parsing sql/schemas/ rather than restating it.
+#
+# Content, not names: a generated file that is *already* dirty and is then
+# rewritten further keeps its name in both snapshots and would otherwise
+# slip through.
+
+set -euo pipefail
+
+cd "$(dirname "$0")/.."
+
+# name + worktree blob hash for every file that differs from the index.
+# A file listed but absent (a deletion) hashes as "gone" rather than
+# aborting the pipeline.
+snapshot() {
+	git diff --name-only | while IFS= read -r f; do
+		if [ -f "$f" ]; then
+			printf '%s %s\n' "$f" "$(git hash-object -- "$f")"
+		else
+			printf '%s gone\n' "$f"
+		fi
+	done
+}
+
+# A brand-new generated file is not in either diff, because it is not
+# tracked at all — the same blind spot bindings-check.sh names.  Both
+# snapshots are taken before the generators run.
+before="$(snapshot)"
+before_untracked="$(git ls-files --others --exclude-standard)"
+
+go generate ./...
+
+after="$(snapshot)"
+after_untracked="$(git ls-files --others --exclude-standard)"
+
+# Symmetric difference, and the symmetry is the whole point.  Generation
+# can push a file *into* the unstaged set (it was current, now it is not)
+# or *out* of it (someone hand-edited generated output and the generator
+# put it back) — and the second is stale generated code just as much as
+# the first.  Comparing one direction only reports "current" for it,
+# which is the failure this script was written to stop.
+moved="$(comm -3 <(printf '%s\n' "$before" | sort) <(printf '%s\n' "$after" | sort) |
+	cut -d' ' -f1 | tr -d '\t' | sort -u | grep -v '^$' || true)"
+
+if [ -n "$moved" ]; then
+	echo "codegen-check: generated code is out of date." >&2
+	echo "Run 'make generate' and stage:" >&2
+	printf '  %s\n' $moved >&2
+	exit 1
+fi
+
+if [ "$after_untracked" != "$before_untracked" ]; then
+	echo "codegen-check: generation produced new files. Stage them:" >&2
+	comm -13 <(printf '%s\n' "$before_untracked" | sort) \
+		<(printf '%s\n' "$after_untracked" | sort) >&2
+	exit 1
+fi
+
+echo "codegen-check: generated code is current"