fix(dav): upsert upload matches server-converted ext (xls→xlsx) (#82)

OnlyOffice converts legacy binary Office uploads (.xls/.doc/.ppt) into
OOXML (.xlsx/.docx/.pptx) on the server. UploadToFolderReplacing matched
by the exact stem|ext via FindFilesByDedupKey, so a repeated
`oo dav upload FOLDER f.xls --replace` never found the stored f.xlsx and
appended a second file (live: ids 3799+3887, 3800+3888).

- EquivalentUploadExt / FindFilesByStemExt: match by stem with a
  legacy↔OOXML extension equivalence, so .xls finds the saved .xlsx.
- planUploadReplacement: pick the surviving file and the redundant
  duplicate ids for a replacing upload.
- UploadToFolderReplacing updates the existing file in place (UpdateFile,
  stable id, no delete window), removes extra duplicates, and falls back
  to conversion-aware delete + upload when the portal rejects the update.
- AssertNoFileConflict (--no-replace) uses the same conversion-aware
  matching so a .xls upload conflicts with an existing .xlsx.
- Offline tests cover the matcher, the plan and the repeated-.xls
  regression; pdf/xlsx behaviour unchanged.

files_replace_test.go

@@ -0,0 +1,120 @@
+package onlyoffice
+
+import (
+	"testing"
+	"time"
+)
+
+func TestEquivalentUploadExt(t *testing.T) {
+	tests := []struct {
+		a, b string
+		want bool
+	}{
+		{".xls", ".xlsx", true},
+		{".XLS", ".xlsx", true},
+		{"xls", "xlsx", true},
+		{".doc", ".docx", true},
+		{".ppt", ".pptx", true},
+		{".pdf", ".pdf", true},
+		{"", "", true},
+		{".xls", ".docx", false},
+		{".xlsx", "", false},
+		{".csv", ".xlsx", false},
+	}
+	for _, tc := range tests {
+		if got := EquivalentUploadExt(tc.a, tc.b); got != tc.want {
+			t.Errorf("EquivalentUploadExt(%q,%q)=%v want %v", tc.a, tc.b, got, tc.want)
+		}
+		if got := EquivalentUploadExt(tc.b, tc.a); got != tc.want {
+			t.Errorf("EquivalentUploadExt(%q,%q)=%v want %v (symmetric)", tc.b, tc.a, got, tc.want)
+		}
+	}
+}
+
+func TestFindFilesByStemExtMatchesConvertedXLS(t *testing.T) {
+	xlsx := &FileEntry{ID: jsonNum("3799"), Title: strPtr("ES29-extracto.xlsx"), FileExst: strPtr(".xlsx")}
+	pdf := &FileEntry{ID: jsonNum("5"), Title: strPtr("ES29-extracto.pdf"), FileExst: strPtr(".pdf")}
+	other := &FileEntry{ID: jsonNum("3887"), Title: strPtr("ES87-extracto.xlsx"), FileExst: strPtr(".xlsx")}
+	files := []*FileEntry{xlsx, pdf, other}
+
+	got := FindFilesByStemExt(files, "ES29-extracto", ".xls")
+	if len(got) != 1 || got[0] != xlsx {
+		t.Fatalf("converted .xls match = %+v, want the saved .xlsx only", got)
+	}
+}
+
+func TestFindFilesByStemExtKeepsExactMatch(t *testing.T) {
+	xlsx := &FileEntry{ID: jsonNum("3799"), Title: strPtr("foo.xlsx"), FileExst: strPtr(".xlsx")}
+	pdf := &FileEntry{ID: jsonNum("5"), Title: strPtr("foo.pdf"), FileExst: strPtr(".pdf")}
+	files := []*FileEntry{xlsx, pdf}
+
+	if got := FindFilesByStemExt(files, "foo", ".xlsx"); len(got) != 1 || got[0] != xlsx {
+		t.Fatalf("exact .xlsx match = %+v, want only xlsx", got)
+	}
+	if got := FindFilesByStemExt(files, "foo", ".pdf"); len(got) != 1 || got[0] != pdf {
+		t.Fatalf("exact .pdf match = %+v, want only pdf", got)
+	}
+	if got := FindFilesByStemExt(files, "foo", ".docx"); len(got) != 0 {
+		t.Fatalf("unrelated ext matched %+v, want none", got)
+	}
+}
+
+func TestFindFilesByStemExtEmptyStem(t *testing.T) {
+	f := &FileEntry{ID: jsonNum("1"), Title: strPtr("foo.xlsx"), FileExst: strPtr(".xlsx")}
+	if got := FindFilesByStemExt([]*FileEntry{f}, "", ".xlsx"); len(got) != 0 {
+		t.Fatalf("empty stem matched %+v, want none", got)
+	}
+}
+
+func TestPlanUploadReplacementFreshUpload(t *testing.T) {
+	plan := planUploadReplacement(nil, "ES29-extracto", ".xls")
+	if plan.UpdateID != "" || len(plan.DeleteIDs) != 0 {
+		t.Fatalf("empty folder plan = %+v, want a fresh upload", plan)
+	}
+}
+
+func TestPlanUploadReplacementUpdatesConvertedFile(t *testing.T) {
+	xlsx := &FileEntry{ID: jsonNum("3799"), Title: strPtr("ES29-extracto.xlsx"), FileExst: strPtr(".xlsx")}
+	plan := planUploadReplacement([]*FileEntry{xlsx}, "ES29-extracto", ".xls")
+	if plan.UpdateID != "3799" {
+		t.Fatalf("UpdateID = %q, want 3799 (update the saved .xlsx in place)", plan.UpdateID)
+	}
+	if len(plan.DeleteIDs) != 0 {
+		t.Fatalf("DeleteIDs = %v, want none", plan.DeleteIDs)
+	}
+}
+
+func TestPlanUploadReplacementCollapsesDuplicates(t *testing.T) {
+	older := time.Date(2026, 9, 1, 10, 0, 0, 0, time.UTC)
+	newer := older.Add(time.Hour)
+	first := &FileEntry{ID: jsonNum("3799"), Title: strPtr("ES29-extracto.xlsx"), FileExst: strPtr(".xlsx"), Updated: &older}
+	second := &FileEntry{ID: jsonNum("3887"), Title: strPtr("ES29-extracto.xlsx"), FileExst: strPtr(".xlsx"), Updated: &newer}
+	plan := planUploadReplacement([]*FileEntry{first, second}, "ES29-extracto", ".xls")
+	if plan.UpdateID != "3887" {
+		t.Fatalf("UpdateID = %q, want the newest duplicate 3887", plan.UpdateID)
+	}
+	if len(plan.DeleteIDs) != 1 || plan.DeleteIDs[0] != 3799 {
+		t.Fatalf("DeleteIDs = %v, want [3799]", plan.DeleteIDs)
+	}
+}
+
+// TestPlanUploadReplacementRepeatedXLS is the regression for #82: the second
+// upload of the same .xls must find the server-converted .xlsx and update it,
+// not append a second file.
+func TestPlanUploadReplacementRepeatedXLS(t *testing.T) {
+	const stem = "ES29-extracto"
+
+	// First upload: nothing in the folder.
+	if plan := planUploadReplacement(nil, stem, ".xls"); plan.UpdateID != "" {
+		t.Fatalf("first upload plan = %+v, want create", plan)
+	}
+	// OnlyOffice converts .xls -> .xlsx on upload; second upload must match it.
+	saved := &FileEntry{ID: jsonNum("3799"), Title: strPtr(stem + ".xlsx"), FileExst: strPtr(".xlsx")}
+	plan := planUploadReplacement([]*FileEntry{saved}, stem, ".xls")
+	if plan.UpdateID != "3799" {
+		t.Fatalf("second upload plan = %+v, want in-place update of 3799 (no duplicate)", plan)
+	}
+	if len(plan.DeleteIDs) != 0 {
+		t.Fatalf("second upload would delete %v, want none", plan.DeleteIDs)
+	}
+}