Ψ-W3 remediation: fix the verify doc's wrong render source, add missing content checks, soften unverified claims

Corrected the Render-dialog source name the refusal's evidence depends on, added a by-ear content check and a file-size channel proxy, and stopped two comments from overclaiming.

src/shell/capture/capture.cpp

@@ -231,23 +231,28 @@ CaptureName captureNameFor(const std::vector<std::string>& sourceNames,
 
 namespace {
 
-// One console line per genuine collapse failure. The capture itself is intact and was
-// measured after this step, so the failure costs only the size win — but silence here is
-// what made a failed rewrite read exactly like a legitimately stereo capture.
-void reportCollapseFailure(const std::string& absolutePath, const char* what) {
-    ShowConsoleMsg(("ReaSampler capture: the lossless mono collapse " + std::string(what) +
-                    " -- " + absolutePath +
-                    " landed intact, as captured.\n").c_str());
+// One console line per genuine collapse failure — silence here is what made a failed
+// rewrite read exactly like a legitimately stereo capture. Deliberately does NOT claim
+// the captured bytes are intact: a 0-byte render can reach this branch too (it passes the
+// exists/bounds gates upstream; see docs/TODO.md), and this path never verified the bytes
+// it's reporting on.
+void reportCollapseFailure(const std::string& absolutePath, const char* what,
+                           const char* consoleLabel) {
+    ShowConsoleMsg((std::string(consoleLabel) + ": the lossless mono collapse " +
+                    std::string(what) + " -- " + absolutePath +
+                    " already reached the bank; only the size win from the collapse "
+                    "was lost.\n").c_str());
 }
 
 }  // namespace
 
-MonoCollapseOutcome collapseCapturedFileToMono(const std::string& absolutePath) {
+MonoCollapseOutcome collapseCapturedFileToMono(const std::string& absolutePath,
+                                               const char* consoleLabel) {
     const std::vector<std::uint8_t> bytes = util::readFileBytes(absolutePath);
     if (bytes.empty()) {
         // Failed, not Declined: the read that would have decided never happened, so
         // "the channels differ" is a claim this path cannot make.
-        reportCollapseFailure(absolutePath, "could not read the captured file");
+        reportCollapseFailure(absolutePath, "could not read the captured file", consoleLabel);
         return MonoCollapseOutcome::Failed;
     }
 
@@ -265,7 +270,7 @@ MonoCollapseOutcome collapseCapturedFileToMono(const std::string& absolutePath)
     {
         std::ofstream out(tempPath, std::ios::binary | std::ios::trunc);
         if (!out) {
-            reportCollapseFailure(absolutePath, "could not open its temporary file");
+            reportCollapseFailure(absolutePath, "could not open its temporary file", consoleLabel);
             return MonoCollapseOutcome::Failed;
         }
         out.write(reinterpret_cast<const char*>(collapse.bytes.data()),
@@ -275,7 +280,7 @@ MonoCollapseOutcome collapseCapturedFileToMono(const std::string& absolutePath)
         if (!wroteOk) {
             std::error_code ec;
             std::filesystem::remove(tempPath, ec);
-            reportCollapseFailure(absolutePath, "could not write the rebuilt file");
+            reportCollapseFailure(absolutePath, "could not write the rebuilt file", consoleLabel);
             return MonoCollapseOutcome::Failed;
         }
     }
@@ -283,7 +288,7 @@ MonoCollapseOutcome collapseCapturedFileToMono(const std::string& absolutePath)
     std::filesystem::rename(tempPath, absolutePath, ec);
     if (ec) {
         std::filesystem::remove(tempPath, ec);  // don't leave litter on a failed rename
-        reportCollapseFailure(absolutePath, "could not replace the captured file");
+        reportCollapseFailure(absolutePath, "could not replace the captured file", consoleLabel);
         return MonoCollapseOutcome::Failed;
     }
     return MonoCollapseOutcome::Collapsed;
@@ -497,8 +502,9 @@ CaptureResult OfflineRenderBackend::capture(const CaptureRequest& request) {
     // (within a tolerance, see below) the requested window's frames, so a source
     // mode that silently widened the render fails loudly here instead of landing as
     // a successful capture. Auto and Manual add frames by design and are skipped.
-    // (The landed file is read three times on this path — this gate, the mono collapse,
-    // and stampCaptureSample — plus one rewrite when the collapse fires; a
+    // (On TailMode::None the landed file is read three times on this path — this gate,
+    // the mono collapse, and stampCaptureSample — plus one rewrite when the collapse
+    // fires; Auto/Manual skip this gate entirely, so they read it twice. A
     // once-per-capture cost on an already-warm file, judged acceptable.) A
     // bounded/header-only read is not a clean substitute: parseWavLayout only marks the
     // data chunk valid when the buffer holds the chunk's FULL declared body

src/shell/capture/capture.h

@@ -80,14 +80,14 @@ struct CaptureRequest {
 // Every failure is an explicit code, never a thrown exception across the REAPER boundary.
 enum class CaptureStatus {
     Ok,
-    NoProject,          // no active project to render / resolve a bank folder
-    EmptyRange,         // start >= end: nothing to render
-    UnsupportedMode,    // backend does not implement this source mode
-    UnsupportedFormat,  // requested bit depth has no known REAPER blob (Float32 only)
-    RenderFailed,       // the render action ran but produced no output file
-    TransportBusy,      // realtime backend: transport already playing/recording — refused
-    MultiTrackSelection,// a selected-tracks render over >1 track — would render N files
-    BoundsMismatch,     // the rendered file's frame count is not the requested window's
+    NoProject,           // no active project to render / resolve a bank folder
+    EmptyRange,          // start >= end: nothing to render
+    UnsupportedMode,     // backend does not implement this source mode
+    UnsupportedFormat,   // requested bit depth has no known REAPER blob (Float32 only)
+    RenderFailed,        // the render action ran but produced no output file
+    TransportBusy,       // realtime backend: transport already playing/recording — refused
+    MultiTrackSelection, // a selected-tracks render over >1 track — would render N files
+    BoundsMismatch,      // the rendered file's frame count is not the requested window's
 };
 
 struct CaptureResult {
@@ -130,7 +130,10 @@ CaptureName captureNameFor(const std::vector<std::string>& sourceNames,
 // A Failed outcome is ALSO logged to the console here, because a successful capture's
 // CaptureResult::message is not printed by any caller — the return value alone would
 // leave a genuine I/O failure indistinguishable from a legitimately stereo capture.
-MonoCollapseOutcome collapseCapturedFileToMono(const std::string& absolutePath);
+// `consoleLabel` matches each caller's own console-prefix convention (offline:
+// "ReaSampler capture"; realtime: "ReaSampler realtime capture").
+MonoCollapseOutcome collapseCapturedFileToMono(const std::string& absolutePath,
+                                               const char* consoleLabel = "ReaSampler capture");
 
 // Stamps the metadata shared by both backends onto `s`: trackGuids (echoed from the
 // request) + channelCount (measured from the produced file's `fmt`; 0/unknown as the

src/shell/capture/capture_realtime_finalize.cpp

@@ -186,7 +186,8 @@ CaptureResult finalizeRecording(ReaProject* proj, MediaTrack* temp,
 
     // Channel-domain rewrite, after the frame-domain trim so it acts on the final
     // frame set; it preserves the frame count, so the trimmed length above still holds.
-    const MonoCollapseOutcome collapseOutcome = collapseCapturedFileToMono(destPath);
+    const MonoCollapseOutcome collapseOutcome =
+        collapseCapturedFileToMono(destPath, "ReaSampler realtime capture");
 
     // Pure recorded-capture -> Sample mapping (identity, bounds echo, tier).
     RecordedCapture cap;

src/shell/capture/capture_realtime_shell.cpp

@@ -32,7 +32,8 @@
 // it never sums back into the master — no feedback, no monitoring double).
 // Multiple selected tracks sum in the one temp track — a real mix, which is why
 // realtime accepts a multi-track selection where the offline track scope refuses
-// it (that render source cannot express a sum; see shell/capture/CLAUDE.md).
+// it (the offline render source is read as emitting one file per track, DAW-
+// unverified — see src/shell/capture/CLAUDE.md §Gotchas).
 //
 // Why this needs no FxBypassGuard: CreateTrackSend defaults to I_SENDMODE=0
 // (post-fader), which taps the source track after its own FX/fader/pan — its