OMC 5.4.1

[abra-code]

OMC 5 requires macOS 14.6 or later. For older macOS versions, use OMC 4.x.

OMC 5.4.1 is a point release on top of 5.4, built against ActionUI 0.9.0. It moves the embedded Python to 3.15.2, adds a Chart element and checkbox lists, and fixes a clipboard bug that could keep a command from running, along with a set of ActionUI layout and input fixes.

Rebuild your applets with AppletBuilder 5.4.1. The ActionUI and engine fixes arrive only when an applet is rebuilt. The new Python does not: it has to be requested, and moving an applet from Python 3.14 to 3.15 is a decision of its own (see the next section).

Embedded Python 3.15.2

The embedded Python shipped in AppletBuilder, and copied into every new Python applet, moves from 3.14.8 to 3.15.2, with OpenSSL 4.1.0 (from 3.6.5), expat 2.9.0 and SQLite 3.54.0. lzma is included, as in 5.4.

Existing applets keep their Python until you ask. Turn on "Update Embedded Python" in Build & Run, or pass --update-python to appletbuilder build. Because 3.14 to 3.15 is a minor-version upgrade, AppletBuilder asks before replacing the runtime. The Build & Run pane now shows the applet's embedded Python version, so you can see which applets are still on 3.14.

Before you upgrade an applet:

• Compiled modules must be reinstalled. A package in Contents/Library/Packages that contains a version-specific extension (a file ending in .cpython-314-darwin.so) does not load in 3.15. Install it again with the 3.15 interpreter. Pure-Python packages, and extensions built for the stable ABI (.abi3.so), keep working.
• Anything installed into the runtime's own site-packages is replaced, as with every Python update. Contents/Library/Packages survives.
• Compute a new thinning plan. A plan made for 3.14 does not describe 3.15's standard library. Thinning now follows 3.15's lazy imports; without that, a thinned 3.15 runtime lost modules such as multiprocessing that the standard library loads on first use, and concurrent.futures.ProcessPoolExecutor failed.

What 3.15 changes for handler scripts:

• UTF-8 is the default encoding. open() and other I/O without an encoding argument read and write UTF-8, whatever the locale the applet was started with. Set PYTHONUTF8=0 to get the old behavior, or pass encoding explicitly.
• Lazy imports (PEP 810): lazy import x and lazy from m import n at module level defer the import until the name is first used, which can shorten a handler's start-up.
• New built-ins frozendict and sentinel, unpacking in comprehensions, and a sampling profiler in profiling.sampling.
• Removed: the sre_compile, sre_constants and sre_parse modules; glob.glob0() and glob.glob1(); pathlib.PurePath.is_reserved() (use os.path.isreserved()); platform.java_ver(); http.server.CGIHTTPRequestHandler; types.CodeType.co_lnotab; ctypes.SetPointerType(); the package parameter of importlib.resources.files(); and keyword-argument NamedTuple and zero-field TypedDict forms in typing.
• Changed: sqlite3.connect() takes every argument except database by keyword only; argparse.add_argument('-f', '-foo') now names the destination foo; base64.urlsafe_b64decode() no longer requires padding; datetime.strptime() raises ValueError for a format with %d and no year; importlib.metadata.metadata() raises MetadataNotFound for a missing package instead of returning an empty result; __cached__ is no longer set on modules.
• Tracebacks and several standard library command-line tools print in color by default. A handler that parses their output should set NO_COLOR=1 or PYTHON_COLORS=0.

Security fixes in 3.15.2 that matter to applets:

• tarfile: the tar extraction filter accepted a link member that resolves to the destination folder itself (CVE-2026-114583).
• ssl: certificate chains that use any of a set of compromised eMudhra intermediate CA keys are now refused (CVE-2026-115557). A connection to a server that relies on one of them fails.
• http.cookiejar: a cookie with a negative Version was accepted without checking its domain against the request host.

Charts

The new Chart element draws Swift Charts from JSON: LineMark, PointMark, BarMark, AreaMark, RuleMark, RectangleMark and SectorMark, grouped with Plot and repeated with ForEach. A chart can have axis marks and label formats, axis domains, color, symbol, line-style and symbol-size scales, annotations drawn next to marks, scrolling with a visible range, and a user selection that becomes the element's value and runs valueChangeActionID.

The data comes either inline in the chart's description or as rows, which a handler fills with the same omc_dialog_control commands as a Table (omc_table_set_rows, omc_table_set_rows_from_stdin and the others). Replace the whole description at runtime with omc_set_property chart '<json>'. The schema, with examples, is in the AppletBuilder documentation under Chart, and the UI editor has a template for it.

Checkbox lists and checkbox columns

• A List (or any data-driven container) whose template is a Toggle becomes a checkbox list. Each row holds its own state in the column that isOn names ("isOn": "$1"). Clicking a checkbox writes "true" or "false" into that row and runs the Toggle's actionID with the row index; it does not select the row. The row's other columns can supply title and disabled.
• A Table column with "viewType": "Toggle" shows a checkbox in every row. The cell text is the state, disabledColumn names a column that disables the checkbox per row, and the column's actionID runs with the row index as its context. Toggling does not change the table's selection.

Rows written by a handler change what the checkboxes show and run no action. The full rules are in the Toggle and Table documentation.

Clipboard text reaches commands again

A command with no text of its own gets $OMC_OBJ_TEXT from the clipboard. Two bugs could make such a command fail without running:

• When no clipboard item offered text, the lookup read past the end of the item's list of types.
• Plain UTF-8 text (public.utf8-plain-text) was never read, so an item whose other text types had been promised by an application that has since quit gave no text at all.

Both are fixed, and UTF-16 text is read correctly when it is empty.

ActionUI fixes

• hidden hides the whole element. A hidden element drew its background, border, overlay and shadow while its content was hidden. Its space is still reserved, as documented.
• ScrollViewReader scrolls. It never moved before. It now scrolls to its target when it appears, and again, animated, whenever a handler writes a target, including the same one again.
• Spacer minLength follows its stack. It is a minimum height in a VStack and a minimum width in an HStack. It used to be applied as a minimum width everywhere.
• DatePicker no longer emits tomorrow's date in the evening. A date-only picker wrote the UTC day, so in time zones west of UTC an evening selection came out as the next day. It now writes the local day. A date string with a zone designator (Z, +02:00) is now read as that instant and shown in the Mac's time zone; before, the designator was dropped.
• Stepper labelFormat: %d and %i show the value instead of 0, a format such as %@ or %s shows the plain value instead of crashing the applet, and the number uses the user's decimal separator (2,5 in a German locale).
• A Slider with a very fine step no longer hangs the applet. SwiftUI keeps every step in memory, so a large range with a small step could use gigabytes. A step that makes more than a million steps is ignored and the slider slides freely.
• A reversed range no longer crashes. A TextField lineLimit or number-format fraction length with its maximum below its minimum stopped the applet; the maximum is now raised to the minimum.
• A read-only TextEditor keeps its text. Typing into it changed the screen but not the value, and undoing that typing could crash. Its text stays selectable.
• keyboardShortcut with "modifiers": [] binds the plain key, so a default button can answer Return and a cancel button Escape. An omitted modifiers still means Command.

AppletBuilder

• Build & Run shows what the applet runs on: its OMC engine version, with the version a build would update it to, and its embedded Python version. Both are read from the applet's files; opening a project never runs its interpreter.
• The Test button runs suites the way a terminal does. A suite started from AppletBuilder inherited AppletBuilder's own environment, so every omc.window() call in a tested applet failed ("nothing could be read from descriptor 3") and AppletBuilder's control values reached handlers where a test set none. Each test file now starts clean. OMCTEST_API_VERSION is unchanged at 7.
• Thinning needs a matching Python. When an applet's runtime is already thinned, the analyzer used to fall back to /usr/bin/python3, which is Python 3.9 and cannot read the 3.14 and 3.15 standard libraries, and the resulting plan quietly missed imports. Thinning now uses only an interpreter at least as new as the applet's, and otherwise stops with a message naming the version it needs.
• codesign_applet.sh no longer gets an applet refused by notarization. A helper built with a plain Xcode build carries the debugger entitlement com.apple.security.get-task-allow, and the script carried it over when re-signing, so the notary service refused the app. Signing with a certificate now drops it and says so; an ad hoc signing keeps it. If you keep your own copy of the script beside an applet, replace it with the one in Scripts/.

Compatibility notes

• PhaseAnimator and KeyframeAnimator are removed. A document that still uses one shows an empty view and logs a warning, and the verifier reports an unknown element type. Use the animation and transition properties of the animated view instead.
• "modifiers": [] in a keyboardShortcut used to mean Command and now means no modifier. Remove the key to keep Command.
• DatePicker values: a date string with a zone designator now means that instant, and a date-only picker reports the local day. A handler that worked around the UTC day should drop the workaround.
• Stepper labels show the user's decimal separator. A handler that parses the label text, rather than the value, should expect it.
• A hidden element with a background or border no longer shows them. Unhide it if that drawing was wanted.
• Python 3.15: see the checklist above before turning on "Update Embedded Python" for an applet with installed packages.

In this distribution

• AppletBuilder.app - OMC applet development studio.
• OnMyCommandCM.plugin - contextual menu plugin for use with Shortcuts.app; commands load from ~/Library/Preferences/com.abracode.OnMyCommandCMPrefs.plist.
• OMCService.service - macOS service template for standalone OMC-based system services.
• Skill/ - the OMC AI agent skill (three flavors) plus its installer.
• Scripts/ - codesign_applet.sh, install_contextual_menu_plugin.sh, thin_distribution.sh, OMCApplet.entitlements, and the example com.abracode.OnMyCommandCMPrefs.plist.

See the main OMC README at https://github.com/abra-code/OMC/ for full documentation on commands, runtime context, dialogs, and services.

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This discussion was created from the release OMC 5.4.1.