fix: assign new IDs to loaded instruments

Fixes #146.

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## Unreleased
 ### Fixed
+- Assign new IDs to loaded instruments, and fix ID collisions in case they
+  somehow still appear ([#146][i146])
 - In x86 templates, do not optimize away phase modulations when unisons are used
   even if all phase inputs are zeros, as unisons use the phase modulation
   mechanism to offset the different oscillators
@@ -176,3 +178,4 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 [i129]: https://github.com/vsariola/sointu/issues/129
 [i130]: https://github.com/vsariola/sointu/issues/130
 [i139]: https://github.com/vsariola/sointu/issues/139
+[i146]: https://github.com/vsariola/sointu/issues/146

tracker/files.go

@@ -171,6 +171,7 @@ success:
 	for len(m.d.Song.Patch) <= m.d.InstrIndex {
 		m.d.Song.Patch = append(m.d.Song.Patch, defaultInstrument.Copy())
 	}
+	m.assignUnitIDs(instrument.Units)
 	m.d.Song.Patch[m.d.InstrIndex] = instrument
 	if m.d.Song.Patch[m.d.InstrIndex].Comment != "" {
 		m.commentExpanded = true

tracker/model.go

@@ -225,6 +225,7 @@ func (m *Model) change(kind string, t ChangeType, severity ChangeSeverity) func(
 				m.send(m.d.Song.Score.Copy())
 			}
 			if m.changeType&PatchChange != 0 {
+				m.fixIDCollisions()
 				m.d.InstrIndex = clamp(m.d.InstrIndex, 0, len(m.d.Song.Patch)-1)
 				m.d.InstrIndex2 = clamp(m.d.InstrIndex2, 0, len(m.d.Song.Patch)-1)
 				unitCount := 0
@@ -441,6 +442,37 @@ func (m *Model) assignUnitIDs(units []sointu.Unit) {
 	}
 }
 
+func (m *Model) fixIDCollisions() {
+	// loop over all instruments and units and check if two units have the same
+	// ID. If so, give the later units new IDs.
+	usedIDs := map[int]bool{}
+	needsFix := false
+	maxID := 0
+	for i, instr := range m.d.Song.Patch {
+		for j, unit := range instr.Units {
+			if usedIDs[unit.ID] {
+				m.d.Song.Patch[i].Units[j].ID = 0
+				needsFix = true
+			}
+			if unit.ID > maxID {
+				maxID = unit.ID
+			}
+			usedIDs[unit.ID] = true
+		}
+	}
+	if needsFix {
+		m.Alerts().Add("Some units had duplicate IDs, they were fixed", Error)
+		for i, instr := range m.d.Song.Patch {
+			for j, unit := range instr.Units {
+				if unit.ID == 0 {
+					maxID++
+					m.d.Song.Patch[i].Units[j].ID = maxID
+				}
+			}
+		}
+	}
+}
+
 func (m *Model) updatePatternUseCount() {
 	for i, track := range m.d.Song.Score.Tracks {
 		for len(m.cachePatternUseCount) <= i {