Run a project inside VS Code: a real terminal by default, output channel optional

[ramedw]

What

Run / Run Selected Project (F9) launched the project's executable detached with its output discarded — a console application's output was gone before anyone could read it. It now runs inside the editor. ddk.projects.runIn picks where:

mode	what you get
terminal (default)	the executable is the process of its own DDK Run: <project> terminal (run parameters applied, cwd = the exe's directory). A real console, so the program's own colors work, the view follows output, and a program reading stdin can be typed into. VS Code reports the exit code. A re-run replaces that project's terminal.
output	stdout/stderr piped into a new DDK Run output channel: header with the exact command line, footer with exit code (or signal) and elapsed time, concurrent runs labelled by project, cleared per run, revealed only once a program actually prints (ddk.projects.runRevealOutput).
detached	the previous behavior.

ddk run (CLI/MCP) is untouched and still launches detached.

Why terminal is the default

A program coloring its output through SetConsoleTextAttribute — DUnitX's test runner, for instance — writes no color information into stdout. The color is an attribute of the console screen buffer's cells, set by a side-channel API call that fails outright once the handle is a pipe. In output mode those colors are therefore unrecoverable by any reader, and the Output panel renders no ANSI escape sequences either. Only a real console produces them, and ConPTY re-encodes them into sequences the terminal draws — which is what a VS Code terminal is.

Consequences for output mode, all documented in the settings and README: plain text (ANSI sequences, carriage-return overwrites and other control characters are stripped rather than shown as ←[32m litter), no keyboard input (a program reading stdin sees EOF), the process is a child of VS Code so closing VS Code breaks its pipe, and VS Code's "smart scroll" stops the panel from following output once the cursor leaves the last line.

Encoding (output mode only)

ddk.projects.runOutputEncoding defaults to ansi — Windows' own default charset for non-Unicode text (GetACP, read from HKLM\SYSTEM\CurrentControlSet\Control\Nls\CodePage\ACP), which is what a program writing to a redirected handle normally produces. Also available: oem (the console codepage chcp reports), utf8 (what a current Delphi RTL emits while redirected), fixed codepages, and auto (per line UTF-8, falling back to ANSI). CP437/850/852 are decoded from built-in tables, since TextDecoder supports no DOS codepage; the tables were generated from and verified byte-exact against .NET's encodings. A terminal decodes its own output, so the setting does not apply there.

Verification

Driven from a console-less parent process, the way the extension host runs, against probes compiled with dcc32 (a console application and a VCL GUI application):

• Output capture end to end: umlauts, en dash, stderr, arguments, exit code 3 — all correct in the channel.
• Encoding matrix: ansi (1252 bytes), oem (CP850 bytes), utf8, auto both ways, explicit cp850; codepage detection returns ACP 1252 / console 850 on the test machine.
• Sanitizing: SGR/256-color/erase/cursor sequences, OSC titles (BEL- and ST-terminated), charset escapes, CR overwrites, BEL, tab preserved — 15 cases.
• Line handling: CRLF and LF, a line straddling two chunks, a multi-byte character split across chunks, unterminated lines flushed when the program goes quiet, blank lines, per-line labels.
• Failure path: a missing executable produces exactly one ✖ … ENOENT footer (error and close both fire on a failed spawn).
• windowsHide suppresses the empty console window a captured console application would otherwise pop up, and does not hide a VCL main form (the VCL ignores the hidden show-command).

npm run check-types, npm run lint (only the 4 warnings that predate this branch, in untouched files) and node esbuild.js are clean.

The version stays [Unreleased] in the changelog — bumping it is a separate release commit, as in this repo's history.

🤖 Generated with Claude Code