## Summary `read-excel-file` throws on any `.xlsx` written by openpyxl that contains an empty-string cell. A single such cell rejects the entire workbook, so no rows are returned at all. Version tested: **9.3.4** (also present in 9.3.x generally; the `inlineStr` branch is unchanged since it was added). ``` Error: Couldn't read "inline string" cell value ``` ## Root cause openpyxl writes a cell holding an empty string as an inline string with **no child element**: ```xml <c r="A2" t="inlineStr"><is><t>Marie</t></is></c> <!-- populated --> <c r="B2" t="inlineStr"></c> <!-- holds "" --> ``` In `source/xlsx/parseCell.js`, `state.inlineString` is only initialised when an `<is>` tag opens: ```js } else if (tagName === 'is') { state.is = true; state.inlineString = ''; } ``` For the second cell no `<is>` ever opens, so `inlineString` stays `undefined`, and `parseCellValue.js` throws: ```js case 'inlineStr': value = inlineString; if (value === undefined) { throw new Error('Couldn\'t read "inline string" cell value'); } ``` The throw escapes the sheet parse, so one empty-string cell fails the whole file. ## Minimal reproduction ```python # openpyxl 3.1.5 from openpyxl import Workbook wb = Workbook() ws = wb.active ws.append(["Nom", "Courriel"]) ws.append(["Marie", ""]) # empty string, not None wb.save("repro.xlsx") ``` ```js import readXlsxFile from 'read-excel-file/node' await readXlsxFile('repro.xlsx') // Error: Couldn't read "inline string" cell value ``` Confirmed to throw on 9.3.4 in both openpyxl's normal and `write_only` modes. Neither mode emits a `sharedStrings.xml`, so every string in these files is an inline string. ## Only an empty string triggers it I generated each case and inspected the resulting XML: | cell value | XML openpyxl writes | breaks | |------------|---------------------|--------| | `""` | `<c r="B2" t="inlineStr"></c>` | **yes** | | `None` | cell omitted from the row entirely | no | | `" "` | `<c r="B2" t="inlineStr"><is><t xml:space="preserve"> </t></is></c>` | no | ## Real-world impact This is not a synthetic edge case. openpyxl is the standard Python route to `.xlsx`, and exporters commonly emit `""` rather than `None` for a missing field. A concrete example from our codebase: a 200-row contact export written by openpyxl 3.1.5 contains 2211 `t="inlineStr"` cells, of which **587** have no `<is>` child. Any one of them alone is fatal, so the file is simply unreadable. ## Suggested fix Treat a missing `<is>` on an `inlineStr` cell as an empty string rather than throwing. Either initialise `inlineString` when the cell opens with `t="inlineStr"`, or default to `''` in the `inlineStr` branch of `parseCellValue`. The spec does expect `<is>` to be present, so openpyxl is arguably at fault. But the reading of a typed cell with no value is unambiguous, other readers (exceljs among them) accept it, and rejecting an entire user-uploaded workbook over it is a harsh outcome. This is the same shape as #68 (`Invalid "shared" string index: undefined`), where a single unresolvable string reference also fails the whole file. If you'd rather keep the strict default, an opt-in such as `{ tolerateInvalidCells: true }` would work just as well for us. ## Current workaround We pre-process the worksheet XML and give bare `inlineStr` cells an empty `<is><t></t></is>` before calling `readSheet`. It works, but it means unzipping and repacking the workbook, which we would like to drop.