Drop a folder or a file onto the window

.github/workflows/ci.yml

@@ -1060,7 +1060,7 @@ jobs:
         # in somebody else's file.
         run: |
           set -euo pipefail
-          watched='internal/format/registry.go internal/damage/damage.go cmd/tfg/main.go internal/gui/window/run.go internal/gui/run_cgo.go internal/gui/window/tidy.go internal/audit/parallel.go internal/engine/parallel.go internal/tool/tool.go internal/gui/window/tools.go internal/gui/window/work.go internal/gui/window/closing.go internal/format/video/ahead.go go.mod .github/workflows/ci.yml .github/build-tags .github/race-weights .github/scripts/race_parts.py'
+          watched='internal/format/registry.go internal/damage/damage.go cmd/tfg/main.go internal/gui/window/run.go internal/gui/run_cgo.go internal/gui/window/tidy.go internal/audit/parallel.go internal/engine/parallel.go internal/tool/tool.go internal/gui/window/tools.go internal/gui/window/work.go internal/gui/window/closing.go internal/gui/window/dropping.go internal/format/video/ahead.go go.mod .github/workflows/ci.yml .github/build-tags .github/race-weights .github/scripts/race_parts.py'
           # On a pull request there is no "before" - the field belongs to a push
           # - so this asked for something empty and every pull request answered
           # "touched". That quietly undid the decision of 2026-08-20, because

CHANGELOG.md

@@ -59,6 +59,14 @@ because it turns other people's test suites red.
 
 ### Added
 
+- **Drop a folder or a file onto the window.** A folder dropped onto Single
+  batch, Presets or Several batches becomes the output directory. On the Tools
+  screen it goes into the box of the chosen tool when the tool takes that
+  kind: a file for `archive-scan`, `checksum` and `checksum-check`, a folder
+  for `checksum-write`. A file where a folder goes, several things at once or
+  a path that is not there is refused under the box, and the box keeps its
+  value. An empty path box says it takes a drop.
+
 - **A new format: `otlp`, OpenTelemetry traces, logs and metrics as OTLP
   JSON.** `tfg generate --format otlp` writes them to an exact size, one batch
   on each line as the OTLP file exporter does (`.jsonl`), or one request for
@@ -201,6 +209,10 @@ because it turns other people's test suites red.
 
 ### Changed
 
+- **On Windows, a path picked with Choose... has backslashes.** It is written
+  the way Windows writes paths, the same text a drop of that folder or file
+  puts in the box. It came with forward slashes before.
+
 - **`empty-and-minimal` now includes `otlp`.** The preset builds the smallest
   file of every format this build has, so with `formats` left at `all` it
   gains an `otlp` target of 1266 B, and the recipe `tfg preset eject
@@ -255,6 +267,9 @@ because it turns other people's test suites red.
 
 ### Fixed
 
+- **Choose... is off while files are being made.** The output directory box
+  was frozen during a run and the button beside it was not, so a folder picked
+  mid run went into the box while the run went on writing into the old one.
 - **An AVIF file asked for just above the size where its picture grows is
   written.** In 0.5.0 about a quarter of the files asked for at 16389 or
   16439 B were not written at all, and the run ended with "1 file could not be

README.md

@@ -824,6 +824,12 @@ behind. The window speaks your system's language when it has it (English and
 Polish today) and English otherwise. Preferences lets you choose another, and
 says what the window keeps between runs.
 
+A folder dropped onto the window becomes the output directory, and on the
+Tools screen a file or a folder dropped onto it goes into the box of the chosen
+tool, the same as picking it with Choose... Drop one at a time. Something the
+box cannot take is refused with a sentence under the box, and the box keeps
+what it had.
+
 <p>
   <img src=".github/window-presets.png" width="49%" alt="The Presets screen of the window, with the list of presets open">
   <img src=".github/window-settings.png" width="49%" alt="One batch of log files in the window, with the settings the log format takes">

internal/guard/concurrency_test.go

@@ -42,6 +42,12 @@ var mayBeConcurrent = map[string]string{
 	// cancels it and waits for it the same way (G7). Added 2026-09-29 with the
 	// Tools tab (docs/NARZEDZIA-SUMY-2026-09-29.md section 12.3).
 	"internal/gui/window/tools.go": "a tool reads beside the window, and closing the window waits for it",
+	// Asking the disk what a dropped path is took 21.0 s for a network path
+	// nobody answers for (measured 2026-11-14, docs/DRAG-DROP-2026-11-14.md
+	// section 12.1), and the window would stand still for all of it. One
+	// os.Stat on a worker, the answer back through fyne.Do, nothing shared but
+	// a count read on the interface thread.
+	"internal/gui/window/dropping.go": "what a dropped path is gets asked beside the window, so a network path that does not answer cannot freeze it",
 	// Signals arrive on a channel by definition, and the handler has to run
 	// beside the work it interrupts.
 	"cmd/tfg/main.go": "the interrupt handler has to run beside the work it stops",