Light/dark themes, A2L syntax colouring, muted noise instead of hidden noise

CHANGELOG.md

@@ -3,6 +3,41 @@
 All notable changes to this project are documented here. Versions follow
 [semantic versioning](https://semver.org/).
 
+## [Unreleased]
+
+## [1.3.0] — 2026-07-31
+
+Read the diff in whichever colour scheme suits the screen, with A2L coloured
+like the rest and noise pushed out of the way instead of out of the file.
+
+### Added
+
+- **Light and dark colour schemes.** Both the viewer and the report can be read
+  either way. `--theme dark|light` sets which one they open with (dark stays the
+  default), the viewer has a switch in its toolbar, and the report carries both
+  schemes inside the file — so its own switch works with no internet, and your
+  choice is remembered for the next report you open.
+- **A2L files are syntax-coloured** in the viewer, keywords and block types
+  apart from the calibration object names — so a name still stands out in a
+  page of ASAM keywords.
+
+### Changed
+
+- **Hiding comment or unimportant differences now greys those lines out instead
+  of removing them.** They keep their place and their line numbers, so the code
+  around a real change is still there to read it in, and they no longer count
+  as changes on the minimap or when stepping through changes.
+- **The report shows unimportant differences when you click their badge**, in
+  grey rather than red or green, so a revealed category still reads as one that
+  does not count. Comment differences stay out of the report entirely — only
+  the count of hidden lines is shown — while the viewer keeps showing them.
+
+### Fixed
+
+- **A model's `_data` companion file is filed under that model** in the report
+  instead of landing in Shared / other, so everything generated for one
+  component is read in one place.
+
 ## [1.2.0] — 2026-07-29
 
 Compare a folder against its own git history, sign off a whole file at once,

CLAUDE.md

@@ -50,12 +50,25 @@ place, `diff_engine._status_of`.
 Only noise verdicts are foldable (`scanner.FOLDABLE`). `real-change`, `added`,
 `deleted` and `error` can **never** be folded away by a UI toggle.
 
+Folding a category in the viewer changes the file's verdict and **greys** its
+rows (`view_model.mute_rows`) — it does not remove them. The lines stay
+readable, and only the "where should I look next" surfaces (minimap, F7/F8)
+stop counting them. Collapsing them to a `⋯ N lines hidden` placeholder was
+tried and reverted: a regenerated file is mostly banner churn, so it took the
+context the surviving hunks have to be read in.
+
 ## 3. One seam per shared decision
 
 Any fact two renderers need lives in **one** module they both import.
-`compare_tool/view_model.py` holds `mode_of`, `char_span` and `aligned_rows`;
-the HTML report and the Qt viewer both consume them, so they cannot disagree
-about what changed or how it is coloured.
+`compare_tool/view_model.py` holds `mode_of`, `char_span`, `aligned_rows` and
+`mute_rows`; `compare_tool/theme.py` holds every colour as a named role, one
+value per theme. The HTML report and the Qt viewer both consume them, so they
+cannot disagree about what changed or how it is coloured.
+
+A colour literal outside `theme.py` is a bug: it paints one theme correctly and
+the other by accident. Add a role to **both** palettes (an import-time assert
+enforces it), then use `var(--role)` in the report's CSS or `theme.c(role)` in
+Qt.
 
 Re-implementing a mapping inline "because it is only four lines" is the bug:
 the copies drift the moment a new kind is added. If you find a duplicated

README.md

@@ -89,6 +89,7 @@ scan did find is still printed.
 | `--exit-zero` | Always exit 0 even when real changes exist (report-only mode for pipelines). Compare errors still exit 2 |
 | `--arxml-only` | Scan only `.arxml`/`.xml`/`.a2l` and write a compact per-type report (default `arxml_update.html`) — always written, even when nothing changed |
 | `--review FILE` | Render notes and sign-offs from a review file (`codegen-review.json`, written by the viewer) next to the changes they belong to, plus a `Reviewed` badge that hides the changes already signed off. Must be named explicitly — a report must not pick up someone else's sign-off by accident; no effect with `--arxml-only` |
+| `--theme dark\|light` | Colour scheme the report and the viewer open with (default `dark`). The report carries **both** and has its own switch, so this only sets what the reader sees first |
 | `--qt`, `--viewer` | Open the side-by-side viewer on folders named on the command line, instead of comparing them in the terminal. Needs the `viewer` extra (see below) |
 
 Omitting `old_dir`/`new_dir` opens the viewer. `--gui` (the tkinter panel) was removed in 1.1.0.
@@ -113,6 +114,8 @@ Reading a scan:
 - `F8` / `F7` step through the changes in the open file and then **carry on into the next (previous) file** with something to review, wrapping at the end. `Ctrl+Home` / `Ctrl+End` stay inside the file.
 - `Ctrl+F` **finds text in the open file** (either side, `F3` / `Shift+F3` to step, `Esc` to close). The query survives moving to another file, so an identifier can be chased across the compare.
 - `Hide identical` leaves only the files with a difference in the tree. It is a view: verdicts, counts and the exported report are untouched.
+- Unticking `Comment` / `Unimportant` **greys those lines out** rather than removing them: they stay where they are, keep their line numbers, lose their red/green, and drop off the minimap and out of `F7`/`F8`. The code around a change is what makes it readable, and a regenerated file is mostly banner churn — folding it away took most of the file with it.
+- `☀ Light` / `☾ Dark` in the toolbar switches the colour scheme; `--theme` picks the one it starts in. C, ARXML and A2L are syntax-coloured in both.
 
 `Review mode` adds the note box and a `Review` column in the tree — green when every change in a row is signed off, amber part way, grey when none is. Sign off one change (`Ctrl+R`) or a whole file (`Ctrl+Shift+R`); the notes travel into the exported report.
 
@@ -138,7 +141,7 @@ A shorter name can stop an argument wrapping at 80 columns, so the two sides hol
 
 Everything else keeps its suffix as meaning. `SIG_TORQUE_MIN` → `SIG_TORQUE_MAX` and `CFG_TIMEOUT_MS` → `CFG_TIMEOUT_US` are real changes, and so are `rtb_AND_…` → `rtb_OR_…` (a different block drives that buffer) and `Sub_…_step` → `Sub_…_Init` (a different entry point). Digits glued to a block name (`rtb_Switch1` vs `rtb_Switch2`) are part of the name, not a mangle tail.
 
-**Comment changes are their own category.** A file whose differences are *only* comments is reported as **Comment**, separate from **Unimportant** (UUIDs, timestamps, SW-VERSION, renames, whitespace) — a rewritten comment banner triages differently from a renamed identifier. Separate counts in the CLI summary and its own tree marker in the viewer. A file mixing comments *with* other noise stays Unimportant. The HTML report keeps the verdict but does not display comment content — see [HTML report](#html-report).
+**Comment changes are their own category.** A file whose differences are *only* comments is reported as **Comment**, separate from **Unimportant** (UUIDs, timestamps, SW-VERSION, renames, whitespace) — a rewritten comment banner triages differently from a renamed identifier. Separate counts in the CLI summary and its own tree marker in the viewer. A file mixing comments *with* other noise stays Unimportant. The viewer has a rule toggle for each; the HTML report gives `Unimportant` a badge and leaves comment lines out altogether — see [HTML report](#html-report).
 
 ## Moved block detection
 
@@ -168,11 +171,13 @@ A file whose XML fails to parse is skipped from this summary (its text diff stil
 
 ## Grouping by model / SWC
 
-Files are grouped by **Simulink model** using the Embedded Coder AUTOSAR naming convention (`X.c`, `X.h`, `X.arxml`, `Rte_X.h`, the modular ARXML set, …). Files that match no model land in a final **Shared / other** group.
+Files are grouped by **Simulink model** using the Embedded Coder AUTOSAR naming convention (`X.c`, `X.h`, `X.arxml`, `Rte_X.h`, `X_data.c`, the modular ARXML set, …). Files that match no model land in a final **Shared / other** group.
 
 ## HTML report
 
-Self-contained file, one per compare: badge toggles, folder tree, filter box, collapsible diffs per file. Opens `Unimportant` hidden and `Modified` expanded, so it opens on what matters.
+Self-contained file, one per compare: badge toggles, folder tree, filter box, collapsible diffs per file. Opens `Unimportant` hidden, `Modified` expanded, so it opens on what matters. Clicking `Unimportant` reveals the actual noise lines — painted flat grey rather than red/green, so a revealed category still reads as "does not count" instead of looking like another change. Comment changes never render in the report at all — only a placeholder states how many comment lines were hidden — the report is a record meant to be sent around, and comment churn is left out of it entirely; the side-by-side viewer still shows them, greyed, for a reviewer working file by file. A `☀ Light` / `☾ Dark` button sits in the top right — both palettes are embedded in the file, so switching fetches nothing and works on a machine with no internet.
+
+A whole file with nothing but comment differences still gets no detail section of its own (there is nothing beyond the comment lines to show); it keeps its own `≉` mark and `Comment` count in the folder tree either way.
 
 ![Report viewer](resources/pic/report_page.png)
 
@@ -230,13 +235,14 @@ compare_tool/
 ├── arxml_rules.py   # ARXML rules: UUID, ADMIN-DATA, DATE, comments + extract port interfaces, SWCs (ports/runnables/events)
 ├── a2l_rules.py     # A2L rules: strip C-style comments + extract CHARACTERISTIC/MEASUREMENT
 ├── view_model.py    # renderer-agnostic view model (paint mode, intra-line span, row alignment) shared by the report and the viewer
-├── syntax.py        # line-at-a-time C / XML token spans, Qt-free so it ships in the .pyz
+├── theme.py         # the dark and light palettes as named roles, shared by the report's CSS and every Qt surface
+├── syntax.py        # line-at-a-time C / XML / A2L token spans, Qt-free so it ships in the .pyz
 ├── review.py        # reviewer notes and sign-offs, keyed by change content so they survive a rescan
 ├── gitsource.py     # read-only `git archive` of a commit into a temp folder, so a commit can be the OLD side
 └── report.py        # self-contained HTML report (badge toggles, model overview, grouping, filter, collapsible diffs)
 ```
 
-[docs/architecture.md](docs/architecture.md) covers how these fit together and why: the two diff passes, where a verdict is decided, the shared seams and the result-dict contract. Anything both renderers need lives in `view_model.py` — reimplementing a mapping inline lets the HTML report and the viewer drift apart about what changed.
+[docs/architecture.md](docs/architecture.md) covers how these fit together and why: the two diff passes, where a verdict is decided, the shared seams and the result-dict contract. Anything both renderers need lives in `view_model.py` (what changed) or `theme.py` (what colour it gets) — reimplementing a mapping inline lets the HTML report and the viewer drift apart.
 
 To add a rule: write the strip function in `c_rules.py` / `arxml_rules.py` / `a2l_rules.py`, join it into that ruleset's shadow, register one labelled variant in `_build_variants` in `diff_engine.py`, and add both tests — the pattern alone is noise, and the same pattern *beside* a real change still reports the real change.
 

compare_tool/__init__.py

@@ -1,3 +1,3 @@
 """CodeGen Compare Tool - AUTOSAR MATLAB codegen diff with noise filtering."""
 
-__version__ = "1.2.0"
+__version__ = "1.3.0"

compare_tool/main.py

@@ -2,14 +2,14 @@
 
 Usage:
     python -m compare_tool <old_dir> <new_dir> [--report out.html] [--arxml-only]
-    python -m compare_tool                     # side-by-side viewer
+    python -m compare_tool [--theme light]     # side-by-side viewer
 """
 
 import argparse
 import sys
 from pathlib import Path
 
-from . import review
+from . import review, theme
 from .diff_engine import RULES
 from .report import build_arxml_report, build_report
 from .scanner import (scan, summarize, summarize_a2l, summarize_ifaces,
@@ -47,7 +47,7 @@ def default_report_name(arxml_only):
 
 
 def run_compare(old_root, new_root, out, arxml_only=False, exclude=(),
-                progress=None, reviews=None):
+                progress=None, reviews=None, theme_name=theme.DEFAULT):
     """Scan two trees and write the HTML report.
     Returns (results, counts). Raises :class:`ReportWriteError` when the report
     could not be written -- a run whose record does not exist is not a run that
@@ -68,9 +68,11 @@ def run_compare(old_root, new_root, out, arxml_only=False, exclude=(),
     if arxml_only:
         # ALWAYS written: "no changes" must be an explicit statement, never
         # a silently absent file (indistinguishable from a run that died)
-        page = build_arxml_report(results, old_root, new_root)
+        page = build_arxml_report(results, old_root, new_root,
+                                  theme_name=theme_name)
     else:
-        page = build_report(results, old_root, new_root, reviews)
+        page = build_report(results, old_root, new_root, reviews,
+                            theme_name=theme_name)
     try:
         out.write_text(page, encoding='utf-8')
     except OSError as e:
@@ -184,6 +186,12 @@ def _parser():
                          'diff report; the report is ALWAYS written -- when '
                          'nothing real changed it states "no changes" '
                          'explicitly per file type')
+    ap.add_argument('--theme', choices=theme.THEMES, default=theme.DEFAULT,
+                    help='colour scheme the viewer opens with, and the one the '
+                         'HTML report opens with (default: dark). The report '
+                         'always carries both, so its own button switches with '
+                         'nothing to download; the viewer has the same button '
+                         'in its toolbar')
     ap.add_argument('--exclude', metavar='PATTERN', action='append', default=[],
                     help='skip files matching this glob (relative path or bare '
                          'file name); repeatable. Example: --exclude compare_report.html')
@@ -230,7 +238,7 @@ def main(argv=None):
         from .qtviewer import run_viewer  # deferred: PySide6 may be absent
         try:
             return run_viewer(args.old_dir, args.new_dir, exclude=args.exclude,
-                              arxml_only=args.arxml_only)
+                              arxml_only=args.arxml_only, theme_name=args.theme)
         except ImportError as e:
             # a stdlib-only install (the .pyz, a locked-down box) has no Qt.
             # Say so plainly instead of dumping a traceback.
@@ -275,7 +283,7 @@ def progress(done, total, rel):
     try:
         results, counts = run_compare(old_root, new_root, out, args.arxml_only,
                                       exclude=args.exclude, progress=progress,
-                                      reviews=reviews)
+                                      reviews=reviews, theme_name=args.theme)
     except ReportWriteError as e:
         # what WAS scanned still goes to the terminal -- the compare itself may
         # have been fine, it is only the record that is missing