fix(m10): item-scope take-FX fingerprint; Windows path case-fold; comments

Item scope now reads the active take's FX chain via TakeFX_* (new
fxChainIdentityForItems helper), not the owning track's chain.
normalizeSlashes lowercases on _WIN32 for detectParent. Stale
comments corrected; case-fold tests added.

src/bank_model.h

@@ -44,8 +44,9 @@ struct SourceRange {
 };
 
 // Present only when a sample was resampled FROM another sample. Carries the
-// parent's id and the FX-chain snapshot string captured at resample time, so the
-// null-test / re-capture-from-source action (M10) can reconstruct the chain.
+// parent's id and the FX-chain snapshot string (a thin drift fingerprint, NOT a
+// restorable chunk) captured at resample time; the re-capture-from-source action
+// (M10) uses it to detect chain drift and replay the original capture request.
 struct Provenance {
     std::string parentSampleId;
     std::string fxChainSnapshot;

src/capture_paths.cpp

@@ -1,6 +1,7 @@
 #include "capture_paths.h"
 
 #include <cassert>
+#include <cctype>
 #include <cstdint>
 #include <cstdio>
 #include <cstring>  // std::memcmp
@@ -124,6 +125,13 @@ std::string normalizeSlashes(const std::string& path) {
     if (out.size() > 1 && out.back() == '/') {
         out.pop_back();
     }
+#ifdef _WIN32
+    // Windows paths are case-insensitive. Fold to lowercase so that two paths
+    // that differ only in drive-letter or component casing compare equal (e.g.
+    // "C:/Foo/BAR.wav" == "c:/foo/bar.wav"). On macOS/Linux, exact case is
+    // preserved (the filesystem is case-sensitive; folding would be wrong).
+    for (char& c : out) c = static_cast<char>(std::tolower(static_cast<unsigned char>(c)));
+#endif
     return out;
 }
 

src/capture_paths.h

@@ -68,6 +68,10 @@ std::string hashWavContent(const std::vector<std::uint8_t>& bytes);
 
 // Normalizes a path to forward slashes and strips any trailing slash. Empty in
 // -> empty out. Pure string transform (does not consult the filesystem).
+// Platform case rule: on Windows (_WIN32) the result is also lowercased so that
+// paths differing only in drive-letter or component casing compare equal (Windows
+// paths are case-insensitive). On macOS/Linux the case is preserved exactly (those
+// filesystems are case-sensitive).
 std::string normalizeSlashes(const std::string& path);
 
 // Sanitizes a caller-supplied base name into a filesystem-safe stem: keeps

src/main.cpp

@@ -438,8 +438,8 @@ static reasampler::ProvenanceScope provenanceScopeFor(reasampler::CaptureScope s
 // fingerprint (P1=a) — scope + source mode + exact range + tail + rate + channels +
 // source track GUIDs + the in-scope source FX-chain identity — so "re-capture from
 // source" can replay the request and report drift. NEVER a serialized chain to
-// restore. Item scope folds an empty FX identity (take/item FX are not enumerable
-// via TrackFX_*); the drift signal then keys on scope+range, which is honest.
+// restore. Item scope reads the active take's TakeFX chain (via TakeFX_*) per
+// selected item, combined in item order; Track scope reads the track FX chain.
 static std::optional<reasampler::Provenance> buildCaptureProvenance(
     const reasampler::CaptureRequest& req,
     reasampler::CaptureScope scope,
@@ -472,15 +472,27 @@ static std::optional<reasampler::Provenance> buildCaptureProvenance(
     recipe.sampleRate   = req.sampleRate;
     recipe.channelCount = req.channelCount;
     recipe.trackGuids   = req.trackGuids;
-    // The in-scope FX-chain identity is the per-track chains combined in track order
-    // (Track scope), length-prefixed so distinct partitions never collide. Item scope
-    // has no readable take-FX chain, so each track folds to an empty identity and the
-    // combined result stays stable/honest (drift then keys on scope + range).
+    // The in-scope FX-chain identity:
+    //   Track scope — per-track chains combined in track order (TrackFX_*).
+    //   Item scope  — per-item active-take chains combined in item order (TakeFX_*);
+    //     the owning track's FX chain is OUT OF SCOPE for an item capture and must
+    //     not be fingerprinted here (it is bypassed during render, not heard).
+    if (scope == reasampler::CaptureScope::Item) {
+        const int n = CountSelectedMediaItems(nullptr);
+        std::vector<MediaItem*> items;
+        items.reserve(static_cast<std::size_t>(n < 0 ? 0 : n));
+        for (int i = 0; i < n; ++i) {
+            MediaItem* it = GetSelectedMediaItem(nullptr, i);
+            if (it) items.push_back(it);
+        }
+        recipe.fxChainIdentity = reasampler::fxChainIdentityForItems(items);
+    } else {
         std::vector<std::string> perTrack;
         perTrack.reserve(src.sourceTracks.size());
         for (MediaTrack* tr : src.sourceTracks)
             perTrack.push_back(reasampler::fxChainIdentityForTrack(tr));
         recipe.fxChainIdentity = reasampler::combineChainIdentities(perTrack);
+    }
 
     reasampler::Provenance prov;
     prov.parentSampleId  = *parentId;
@@ -883,12 +895,26 @@ static void RunRecaptureFromSource()
     req.trackGuids   = recipe->trackGuids;
 
     // Read the CURRENT source FX-chain identity BEFORE the render bypasses it, to
-    // compare against the recorded identity for drift reporting.
+    // compare against the recorded identity for drift reporting. Mirror the same
+    // scope split as buildCaptureProvenance: item scope reads take FX via TakeFX_*;
+    // track scope reads the track FX chain via TrackFX_*.
+    std::string currentIdentity;
+    if (scope == reasampler::CaptureScope::Item) {
+        const int n = CountSelectedMediaItems(nullptr);
+        std::vector<MediaItem*> items;
+        items.reserve(static_cast<std::size_t>(n < 0 ? 0 : n));
+        for (int i = 0; i < n; ++i) {
+            MediaItem* it = GetSelectedMediaItem(nullptr, i);
+            if (it) items.push_back(it);
+        }
+        currentIdentity = reasampler::fxChainIdentityForItems(items);
+    } else {
         std::vector<std::string> perTrackNow;
         perTrackNow.reserve(sourceTracks.size());
         for (MediaTrack* tr : sourceTracks)
             perTrackNow.push_back(reasampler::fxChainIdentityForTrack(tr));
-    const std::string currentIdentity = reasampler::combineChainIdentities(perTrackNow);
+        currentIdentity = reasampler::combineChainIdentities(perTrackNow);
+    }
     const bool drifted = (currentIdentity != recipe->fxChainIdentity);
 
     // Render (bank-only; renderOffline never touches the timeline).
@@ -918,6 +944,10 @@ static void RunRecaptureFromSource()
     updated.captureTempo  = res.sample.captureTempo;
     updated.trackGuids    = res.sample.trackGuids;
     updated.createdTimestamp = res.sample.createdTimestamp;
+    // NOTE: levels, clipped, and lengthBeats are carried from the original (via the
+    // *orig copy above) because the offline backend does not populate them today
+    // (res.sample leaves them at defaults). If a later milestone populates these
+    // fields at capture time, refresh them here from res.sample instead.
     reasampler::Provenance prov;
     prov.parentSampleId  = recordedParentId;
     prov.fxChainSnapshot = reasampler::buildFingerprint(refreshed);

src/provenance.h

@@ -46,13 +46,14 @@ enum class ProvenanceScope {
     Track,
 };
 
-// One FX-chain entry as the shell reads it from REAPER (TrackFX_GetFXName /
-// TrackFX_GetFXGUID / TrackFX_GetEnabled). Plain data — the shell fills it, the
+// One FX-chain entry as the shell reads it from REAPER. For Track scope the shell
+// uses TrackFX_GetFXName/GetFXGUID/GetEnabled; for Item scope it uses the TakeFX_*
+// equivalents over the active take's FX chain. Plain data — the shell fills it, the
 // pure fold turns the vector into the identity string.
 struct FxIdentityEntry {
-    std::string name;     // TrackFX_GetFXName
-    std::string guid;     // TrackFX_GetFXGUID -> guidToString (per-instance identity)
-    bool        enabled;  // TrackFX_GetEnabled
+    std::string name;     // TrackFX_GetFXName / TakeFX_GetFXName
+    std::string guid;     // TrackFX_GetFXGUID / TakeFX_GetFXGUID -> guidToString
+    bool        enabled;  // TrackFX_GetEnabled / TakeFX_GetEnabled
 };
 
 // The recorded capture recipe + source FX-chain identity — the thin fingerprint.
@@ -138,8 +139,9 @@ struct BankFileRef {
 //
 // Returns the parent sample id, or nullopt when the capture is not a genuine
 // resample-from-sample. Comparison is exact path identity; the caller normalizes
-// both sides identically so a slash/case difference never spuriously matches or
-// misses (case handling is the caller's normalization contract, not decided here).
+// both sides identically via normalizeSlashes (which lowercases on Windows) so a
+// slash/case difference never spuriously matches or misses. On Windows both sides
+// are lowercased before they reach here; on macOS/Linux they are case-exact.
 std::optional<std::string> detectParent(
     const std::vector<std::string>& sourceItemFiles,
     const std::vector<BankFileRef>& bankFiles);

src/provenance_shell.cpp

@@ -8,6 +8,10 @@
 //   * TrackFX_GetFXName(MediaTrack*, int, char*, int) -> bool       (~7356)
 //   * TrackFX_GetFXGUID(MediaTrack*, int) -> GUID*                  (~7348)
 //   * TrackFX_GetEnabled(MediaTrack*, int) -> bool                  (~7291)
+//   * TakeFX_GetCount(MediaItem_Take*)                              (~6710)
+//   * TakeFX_GetFXName(MediaItem_Take*, int, char*, int) -> bool    (~6758)
+//   * TakeFX_GetFXGUID(MediaItem_Take*, int) -> GUID*               (~6750)
+//   * TakeFX_GetEnabled(MediaItem_Take*, int) -> bool               (~6718)
 //   * CountSelectedMediaItems / GetSelectedMediaItem                (selection reads)
 //   * GetActiveTake(MediaItem*) -> MediaItem_Take*                  (active take)
 //   * GetMediaItemTake_Source(MediaItem_Take*) -> PCM_source*       (~2053)
@@ -28,6 +32,10 @@
 #define REAPERAPI_WANT_TrackFX_GetFXName
 #define REAPERAPI_WANT_TrackFX_GetFXGUID
 #define REAPERAPI_WANT_TrackFX_GetEnabled
+#define REAPERAPI_WANT_TakeFX_GetCount
+#define REAPERAPI_WANT_TakeFX_GetFXName
+#define REAPERAPI_WANT_TakeFX_GetFXGUID
+#define REAPERAPI_WANT_TakeFX_GetEnabled
 #define REAPERAPI_WANT_CountSelectedMediaItems
 #define REAPERAPI_WANT_GetSelectedMediaItem
 #define REAPERAPI_WANT_CountTrackMediaItems
@@ -67,6 +75,37 @@ std::string fxChainIdentityForTrack(MediaTrack* tr) {
     return fxChainIdentity(rows);
 }
 
+std::string fxChainIdentityForItems(const std::vector<MediaItem*>& items) {
+    // For Item scope the in-scope chain is each item's active take's FX chain, NOT
+    // the owning track's FX chain (the track chain is out-of-scope and is bypassed
+    // during render). TakeFX_* is the correct family here.
+    std::vector<std::string> perItem;
+    perItem.reserve(items.size());
+    for (MediaItem* it : items) {
+        if (!it) { perItem.push_back(fxChainIdentity({})); continue; }
+        MediaItem_Take* take = GetActiveTake(it);
+        if (!take) { perItem.push_back(fxChainIdentity({})); continue; }
+        std::vector<FxIdentityEntry> rows;
+        const int n = TakeFX_GetCount(take);
+        rows.reserve(static_cast<std::size_t>(n < 0 ? 0 : n));
+        for (int i = 0; i < n; ++i) {
+            FxIdentityEntry e;
+            char nameBuf[512] = {0};
+            if (TakeFX_GetFXName(take, i, nameBuf, static_cast<int>(sizeof(nameBuf))))
+                e.name = nameBuf;
+            if (GUID* g = TakeFX_GetFXGUID(take, i)) {
+                char gb[64] = {0};
+                guidToString(g, gb);
+                e.guid = gb;
+            }
+            e.enabled = TakeFX_GetEnabled(take, i);
+            rows.push_back(std::move(e));
+        }
+        perItem.push_back(fxChainIdentity(rows));
+    }
+    return combineChainIdentities(perItem);
+}
+
 namespace {
 // The active take source file of one item, normalized. Empty if unresolvable.
 std::string itemSourceFile(MediaItem* it) {

src/provenance_shell.h

@@ -22,20 +22,26 @@
 #include "provenance.h"
 
 class MediaTrack;
+class MediaItem;
 
 namespace reasampler {
 
 class BankBook;
 
-// The in-scope FX-chain identity of a source track, folded to the pure
-// provenance string. For TRACK scope this is the track's own FX chain; for ITEM
-// scope the take/item FX are the in-scope chain — but item/take FX are not
-// enumerable via the TrackFX_* family, so an item-scope capture folds an EMPTY
-// chain identity (the drift signal then keys on scope + range only, which is
-// honest: we do not claim to fingerprint take FX we cannot read). TRACK scope reads
-// TrackFX_GetCount / GetFXName / GetFXGUID / GetEnabled in chain order.
+// The in-scope FX-chain identity of a source track (Track scope), folded to the
+// pure provenance string. Reads the track's own FX chain via TrackFX_GetCount /
+// TrackFX_GetFXName / TrackFX_GetFXGUID / TrackFX_GetEnabled in chain order.
 std::string fxChainIdentityForTrack(MediaTrack* tr);
 
+// The in-scope FX-chain identity for Item scope: enumerates each item's active
+// take FX chain via TakeFX_GetCount / TakeFX_GetFXName / TakeFX_GetFXGUID /
+// TakeFX_GetEnabled, in item order then FX order, combined with
+// combineChainIdentities so distinct per-item partitions never collide. Returns
+// the combined identity string (empty combined identity for a no-FX or no-item
+// set). The items vector is the same source-item set the shell collected for the
+// item-scope capture (selected items whose owning tracks were also collected).
+std::string fxChainIdentityForItems(const std::vector<MediaItem*>& items);
+
 // Reads the media-file path of every SELECTED media item's active take source
 // (GetMediaItemTake_Source -> GetMediaSourceFileName), normalized to forward-slash.
 // Unresolvable items (no take / no source / empty name) are omitted — never an

tests/test_capture_paths.cpp

@@ -18,12 +18,40 @@ static int g_fail = 0;
     std::printf("FAIL line %d: %s\n", __LINE__, #cond); ++g_fail; } } while(0)
 
 static void testNormalizeSlashes() {
-    CHECK(normalizeSlashes("C:\\a\\b") == "C:/a/b");
+#ifdef _WIN32
+    // On Windows paths are lowercased for case-insensitive comparison.
+    CHECK(normalizeSlashes("C:\\a\\b") == "c:/a/b");
     CHECK(normalizeSlashes("a/b/c") == "a/b/c");
     CHECK(normalizeSlashes("a/b/") == "a/b");        // trailing slash stripped
     CHECK(normalizeSlashes("a\\b\\") == "a/b");       // backslash + trailing
     CHECK(normalizeSlashes("/") == "/");              // lone root preserved
     CHECK(normalizeSlashes("") == "");                // empty stays empty
+#else
+    CHECK(normalizeSlashes("C:\\a\\b") == "C:/a/b");
+    CHECK(normalizeSlashes("a/b/c") == "a/b/c");
+    CHECK(normalizeSlashes("a/b/") == "a/b");
+    CHECK(normalizeSlashes("a\\b\\") == "a/b");
+    CHECK(normalizeSlashes("/") == "/");
+    CHECK(normalizeSlashes("") == "");
+#endif
+}
+
+// Windows case-folding: paths differing only in casing must compare equal after
+// normalizeSlashes, since Windows paths are case-insensitive. On non-Windows the
+// function is case-preserving (filesystem is case-sensitive).
+static void testNormalizeSlashesCaseFolding() {
+#ifdef _WIN32
+    // Drive letter and component casing differences are neutralized.
+    CHECK(normalizeSlashes("C:/Foo/BAR.wav") == normalizeSlashes("c:/foo/bar.wav"));
+    CHECK(normalizeSlashes("C:/Foo/BAR.wav") == "c:/foo/bar.wav");
+    // Mixed-case input produces consistently lowercase output.
+    CHECK(normalizeSlashes("C:\\Users\\Daniel\\Proj\\File.WAV")
+          == "c:/users/daniel/proj/file.wav");
+#else
+    // Non-Windows: case is preserved exactly (case-sensitive filesystem).
+    CHECK(normalizeSlashes("C:/Foo/BAR.wav") != normalizeSlashes("c:/foo/bar.wav"));
+    CHECK(normalizeSlashes("C:/Foo/BAR.wav") == "C:/Foo/BAR.wav");
+#endif
 }
 
 static void testSanitizeStem() {
@@ -57,7 +85,12 @@ static void testDeriveRelativePathIsProjectRelative() {
 static void testDeriveAbsoluteDirJoinsProjectDir() {
     BankPaths p = deriveBankPaths("C:\\Users\\d\\proj", "kick", "");
     // Backslashes normalized; bank subfolder appended; no trailing slash.
+    // On Windows the drive-letter + components are lowercased by normalizeSlashes.
+#ifdef _WIN32
+    CHECK(p.absoluteDir == "c:/users/d/proj/reasampler_bank");
+#else
     CHECK(p.absoluteDir == "C:/Users/d/proj/reasampler_bank");
+#endif
     // No unique tag -> stem has no trailing "_".
     CHECK(p.fileName == "kick.wav");
     CHECK(p.relativePath == "reasampler_bank/kick.wav");
@@ -116,7 +149,15 @@ static void testFileStem() {
 
 static void testResolveBankFileAgainstProjectDir() {
     // A relative index entry resolves to <projectDir>/<relativePath>, forward-
-    // slashed, regardless of the input slash style.
+    // slashed, regardless of the input slash style. On Windows the result is also
+    // lowercased (Windows paths are case-insensitive; normalizeSlashes folds them).
+#ifdef _WIN32
+    CHECK(resolveBankFile("C:\\Users\\d\\proj", "reasampler_bank/kick.wav")
+          == "c:/users/d/proj/reasampler_bank/kick.wav");
+    // Backslashes in the stored relative path are normalized on resolution.
+    CHECK(resolveBankFile("C:/p", "reasampler_bank\\a.wav")
+          == "c:/p/reasampler_bank/a.wav");
+#else
     CHECK(resolveBankFile("C:\\Users\\d\\proj", "reasampler_bank/kick.wav")
           == "C:/Users/d/proj/reasampler_bank/kick.wav");
     CHECK(resolveBankFile("/home/d/proj", "reasampler_bank/mix.wav")
@@ -127,6 +168,7 @@ static void testResolveBankFileAgainstProjectDir() {
     // Backslashes in the stored relative path are normalized on resolution.
     CHECK(resolveBankFile("/p", "reasampler_bank\\a.wav")
           == "/p/reasampler_bank/a.wav");
+#endif
 }
 
 static void testResolveBankFileRejectsEmptyInputs() {
@@ -159,10 +201,16 @@ static void testResolveAgainstNewProjectDirAfterSaveAs() {
 static void testRelocationPlanForSaveAs() {
     // Save-As to a different directory: relocation is needed; both bank dirs are
     // <projectDir>/reasampler_bank, forward-slashed, no trailing slash.
+    // On Windows the drive-letter and path components are lowercased.
     BankRelocation r = deriveRelocationPlan("C:\\old\\proj", "C:/new/proj");
     CHECK(r.needed);
+#ifdef _WIN32
+    CHECK(r.oldBankDir == "c:/old/proj/reasampler_bank");
+    CHECK(r.newBankDir == "c:/new/proj/reasampler_bank");
+#else
     CHECK(r.oldBankDir == "C:/old/proj/reasampler_bank");
     CHECK(r.newBankDir == "C:/new/proj/reasampler_bank");
+#endif
 }
 
 static void testRelocationPlanNotNeededForSaveInPlace() {
@@ -501,6 +549,7 @@ static void testHashWavContentDomainSeparationFromWholeFile() {
 
 int main() {
     testNormalizeSlashes();
+    testNormalizeSlashesCaseFolding();
     testSanitizeStem();
     testDeriveRelativePathIsProjectRelative();
     testDeriveAbsoluteDirJoinsProjectDir();