fix: Release reader lock on exceptions

Author: effigies

src/files/tsv.ts

@@ -14,45 +14,47 @@ async function _loadTSV(file: BIDSFile, maxRows: number = -1): Promise<ColumnsMa
     .pipeThrough(new TextLineStream())
     .getReader()
 
-  const headerRow = await reader.read()
-  const headers = (headerRow.done || !headerRow.value) ? [] : headerRow.value.split('\t')
-
-  // Initialize columns in array for construction efficiency
-  const initialCapacity = maxRows >= 0 ? maxRows : 1000
-  const columns: string[][] = headers.map(() => new Array<string>(initialCapacity))
-
-  maxRows = maxRows >= 0 ? maxRows : Infinity
-  let rowIndex = 0 // Keep in scope after loop
-  for (; rowIndex < maxRows; rowIndex++) {
-    const { done, value } = await reader.read()
-    if (done) break
-
-    // Expect a newline at the end of the file, but otherwise error on empty lines
-    if (!value) {
-      const nextRow = await reader.read()
-      if (nextRow.done) break
-      throw { key: 'TSV_EMPTY_LINE', line: rowIndex + 2 }
-    }
-
-    const values = value.split('\t')
-    if (values.length !== headers.length) {
-      throw { key: 'TSV_EQUAL_ROWS', line: rowIndex + 2 }
-    }
-    columns.forEach((column, columnIndex) => {
-      // Double array size if we exceed the current capacity
-      if (rowIndex >= column.length) {
-        column.length = column.length * 2
+  try {
+    const headerRow = await reader.read()
+    const headers = (headerRow.done || !headerRow.value) ? [] : headerRow.value.split('\t')
+
+    // Initialize columns in array for construction efficiency
+    const initialCapacity = maxRows >= 0 ? maxRows : 1000
+    const columns: string[][] = headers.map(() => new Array<string>(initialCapacity))
+
+    maxRows = maxRows >= 0 ? maxRows : Infinity
+    let rowIndex = 0 // Keep in scope after loop
+    for (; rowIndex < maxRows; rowIndex++) {
+      const { done, value } = await reader.read()
+      if (done) break
+
+      // Expect a newline at the end of the file, but otherwise error on empty lines
+      if (!value) {
+        const nextRow = await reader.read()
+        if (nextRow.done) break
+        throw { key: 'TSV_EMPTY_LINE', line: rowIndex + 2 }
       }
-      column[rowIndex] = values[columnIndex]
-    })
-  }
 
-  reader.releaseLock()
+      const values = value.split('\t')
+      if (values.length !== headers.length) {
+        throw { key: 'TSV_EQUAL_ROWS', line: rowIndex + 2 }
+      }
+      columns.forEach((column, columnIndex) => {
+        // Double array size if we exceed the current capacity
+        if (rowIndex >= column.length) {
+          column.length = column.length * 2
+        }
+        column[rowIndex] = values[columnIndex]
+      })
+    }
 
-  // Construct map, truncating columns to number of rows read
-  return new ColumnsMap(
-    headers.map((header, index) => [header, columns[index].slice(0, rowIndex)]),
-  )
+    // Construct map, truncating columns to number of rows read
+    return new ColumnsMap(
+      headers.map((header, index) => [header, columns[index].slice(0, rowIndex)]),
+    )
+  } finally {
+    reader.releaseLock()
+  }
 }
 
 export const loadTSV = filememoizeAsync(_loadTSV)