fix

fetch.bs

@@ -590,7 +590,7 @@ user-agent-defined <a for=header>value</a> for the
  <li><p>A <dfn export for=body id=concept-body-total-bytes>total bytes</dfn> (an
  integer), initially 0.
 
- <li><p>A <dfn export for=body id=concept-body-replayable>replayable flag</dfn>, initially unset.
+ <li><p>A <dfn export for=body id=concept-body-source>source</dfn>, initially null.
 </ul>
 
 <p>A <a for=/>body</a> <var>body</var> is said to be
@@ -3029,8 +3029,7 @@ in addition to <a>HTTP fetch</a> above.
 
  <li><p>If <var>actualResponse</var>'s <a for=response>status</a> is not <code>303</code>,
  <var>request</var>'s <a for=request>body</a> is non-null, and <var>request</var>'s
- <a for=request>body</a>'s <a for=body>replayable flag</a> is unset, then return a
- <a>network error</a>.
+ <a for=request>body</a>'s <a for=body>source</a> is null, then return a <a>network error</a>.
 
  <li>
   <p>If <i>CORS flag</i> is set and <var>actualResponse</var>'s
@@ -3056,6 +3055,17 @@ in addition to <a>HTTP fetch</a> above.
  to `<code>GET</code>` and <var>request</var>'s <a for=request>body</a>
  to null.
 
+ <li>
+  <p>If <var>request</var>'s <a for=request>body</a> is not null, then set <var>request</var>'s
+  <a for=request>body</a> to the first part of <a lt=extract for=BodyInit>extracting</a>
+  <var>request</var>'s <a for=request>body</a>'s <a for=body>source</a>.
+
+  <p class="note no-backref"><var>request</var>'s <a for=request>body</a>'s <a for=body>source</a>'s
+  nullity has already been checked.
+
+  <p class="note no-backref">The <a lt=extract for=BodyInit>extracting</a> operation cannot throw
+  as it was called for the same <a for=body>source</a> before.
+
  <li><p>Append <var>actualResponse</var>'s
  <a for=response>location URL</a> to <var>request</var>'s
  <a for=request>url list</a>.
@@ -3091,8 +3101,7 @@ steps:
   <var>request</var> otherwise.
 
   <p class="note no-backref">A <var>request</var> is typically cloned as it needs to be possible to
-  add <a>headers</a> and read its
-  <a for=request>body</a> without affecting <var>request</var>. As
+  add <a>headers</a> without affecting <var>request</var>. As
   <var>request</var> is reused with redirects, authentication, and proxy authentication.
 
  <li>
@@ -3373,9 +3382,22 @@ steps:
    <li class=XXX><p>Needs testing: multiple `<code>WWW-Authenticate</code>` headers, missing,
    parsing issues.
 
-   <li><p>If <var>request</var>'s <a for=request>body</a> is non-null and <var>request</var>'s
-   <a for=request>body</a>'s <a for=body>replayable flag</a> is unset, then return a
-   <a>network error</a>.
+   <li>
+    <p>If <var>request</var>'s <a for=request>body</a> is non-null, then run these subsubsteps:
+
+    <ol>
+     <li><p>If <var>request</var>'s <a for=request>body</a>'s <a for=body>source</a> is null,
+     then return a <a>network error</a>.
+
+     <li>
+      <p>
+      <p>Set <var>request</var>'s <a for=request>body</a> to the first part of
+      <a lt=extract for=BodyInit>extracting</a> <var>request</var>'s <a for=request>body</a>'s
+      <a for=body>source</a>.
+
+      <p class="note no-backref">The <a lt=extract for=BodyInit>extracting</a> operation cannot
+      throw as it was called for the same <a for=body>source</a> before.
+    </ol>
 
    <li>
     <p>If <var>request</var>'s
@@ -4266,7 +4288,7 @@ typedef (Blob or BufferSource or FormData or URLSearchParams or ReadableStream o
 
  <li><p>Let <var>action</var> be null.
 
- <li><p>Let <var>replayable</var> be false.
+ <li><p>Let <var>source</var> be null.
 
  <li>
   <p>Switch on <var>object</var>'s type:
@@ -4279,7 +4301,7 @@ typedef (Blob or BufferSource or FormData or URLSearchParams or ReadableStream o
     <p>If <var>object</var>'s {{Blob/type}}
     attribute is not the empty byte sequence, set <var>Content-Type</var> to its value.
 
-    <p>Set <var>replayable</var> to true.
+    <p>Set <var>source</var> to object.
 
    <dt><code>BufferSource</code>
    <dd>
@@ -4289,7 +4311,7 @@ typedef (Blob or BufferSource or FormData or URLSearchParams or ReadableStream o
     <var>stream</var>. If that threw an exception,
     <a abstract-op>error</a> <var>stream</var> with that exception.
 
-    <p>Set <var>replayable</var> to true.
+    <p>Set <var>source</var> to object.
 
    <dt>{{FormData}}
    <dd>
@@ -4303,7 +4325,7 @@ typedef (Blob or BufferSource or FormData or URLSearchParams or ReadableStream o
     <a><code>multipart/form-data</code> boundary string</a> generated by the
     <a><code>multipart/form-data</code> encoding algorithm</a>.
 
-    <p>Set <var>replayable</var> to true.
+    <p>Set <var>source</var> to object.
 
    <dt>{{URLSearchParams}}
    <dd>
@@ -4316,15 +4338,15 @@ typedef (Blob or BufferSource or FormData or URLSearchParams or ReadableStream o
     <p>Set <var>Content-Type</var> to
     `<code>application/x-www-form-urlencoded;charset=UTF-8</code>`.
 
-    <p>Set <var>replayable</var> to true.
+    <p>Set <var>source</var> to object.
 
    <dt><code>USVString</code>
    <dd>
     <p>Set <var>action</var> to an action that runs <a>utf-8 encode</a> on <var>object</var>.
 
     <p>Set <var>Content-Type</var> to `<code>text/plain;charset=UTF-8</code>`.
 
-    <p>Set <var>replayable</var> to true.
+    <p>Set <var>source</var> to object.
 
    <dt>{{ReadableStream}}
    <dd><p>Set <var>stream</var> to <var>object</var>.
@@ -4350,9 +4372,7 @@ typedef (Blob or BufferSource or FormData or URLSearchParams or ReadableStream o
   </ol>
 
  <li><p>Let <var>body</var> be a <a for=/>body</a> whose <a for=body>stream</a> is
- <var>stream</var>.
-
- <li><p>Set <var>body</var>'s <a for=body>replayable flag</a> if <var>replayable</var> is true.
+ <var>stream</var> and whose <a fore=body>source</a> is <var>source</var>.
 
  <li><p>Return <var>body</var> and <var>Content-Type</var>.
 </ol>