--- a/mercurial/cmdutil.py	Wed Jul 07 15:09:26 2021 +0200
+++ b/mercurial/cmdutil.py	Fri Jul 02 11:44:13 2021 -0700
@@ -346,19 +346,18 @@
     return isinstance(x, hunkclasses)
 
 
-def newandmodified(chunks, originalchunks):
+def isheader(x):
+    headerclasses = (crecordmod.uiheader, patch.header)
+    return isinstance(x, headerclasses)
+
+
+def newandmodified(chunks):
     newlyaddedandmodifiedfiles = set()
     alsorestore = set()
     for chunk in chunks:
-        if (
-            ishunk(chunk)
-            and chunk.header.isnewfile()
-            and chunk not in originalchunks
-        ):
-            newlyaddedandmodifiedfiles.add(chunk.header.filename())
-            alsorestore.update(
-                set(chunk.header.files()) - {chunk.header.filename()}
-            )
+        if isheader(chunk) and chunk.isnewfile():
+            newlyaddedandmodifiedfiles.add(chunk.filename())
+            alsorestore.update(set(chunk.files()) - {chunk.filename()})
     return newlyaddedandmodifiedfiles, alsorestore
 
 
@@ -517,12 +516,12 @@
         diffopts.git = True
         diffopts.showfunc = True
         originaldiff = patch.diff(repo, changes=status, opts=diffopts)
-        originalchunks = patch.parsepatch(originaldiff)
+        original_headers = patch.parsepatch(originaldiff)
         match = scmutil.match(repo[None], pats)
 
         # 1. filter patch, since we are intending to apply subset of it
         try:
-            chunks, newopts = filterfn(ui, originalchunks, match)
+            chunks, newopts = filterfn(ui, original_headers, match)
         except error.PatchError as err:
             raise error.InputError(_(b'error parsing patch: %s') % err)
         opts.update(newopts)
@@ -532,15 +531,11 @@
         # version without the edit in the workdir. We also will need to restore
         # files that were the sources of renames so that the patch application
         # works.
-        newlyaddedandmodifiedfiles, alsorestore = newandmodified(
-            chunks, originalchunks
-        )
+        newlyaddedandmodifiedfiles, alsorestore = newandmodified(chunks)
         contenders = set()
         for h in chunks:
-            try:
+            if isheader(h):
                 contenders.update(set(h.files()))
-            except AttributeError:
-                pass
 
         changed = status.modified + status.added + status.removed
         newfiles = [f for f in changed if f in contenders]
@@ -3630,12 +3625,12 @@
             diff = patch.diff(repo, None, ctx.node(), m, opts=diffopts)
         else:
             diff = patch.diff(repo, ctx.node(), None, m, opts=diffopts)
-        originalchunks = patch.parsepatch(diff)
+        original_headers = patch.parsepatch(diff)
 
         try:
 
             chunks, opts = recordfilter(
-                repo.ui, originalchunks, match, operation=operation
+                repo.ui, original_headers, match, operation=operation
             )
             if operation == b'discard':
                 chunks = patch.reversehunks(chunks)
@@ -3648,9 +3643,7 @@
         # "remove added file <name> (Yn)?", so we don't need to worry about the
         # alsorestore value. Ideally we'd be able to partially revert
         # copied/renamed files.
-        newlyaddedandmodifiedfiles, unusedalsorestore = newandmodified(
-            chunks, originalchunks
-        )
+        newlyaddedandmodifiedfiles, unusedalsorestore = newandmodified(chunks)
         if tobackup is None:
             tobackup = set()
         # Apply changes

--- a/tests/test-commit-interactive.t	Wed Jul 07 15:09:26 2021 +0200
+++ b/tests/test-commit-interactive.t	Fri Jul 02 11:44:13 2021 -0700
@@ -1713,20 +1713,58 @@
   record this change to 'plain3'?
   (enter ? for help) [Ynesfdaq?] y
   
+
+Rename file but discard edits
+
+  $ echo content > new-file
+  $ hg add -q new-file
+  $ hg commit -qm 'new file'
+  $ hg mv new-file renamed-file
+  $ echo new-content >> renamed-file
+  $ hg commit -i -d '24 0' -m content-rename<<EOF
+  > y
+  > n
+  > EOF
+  diff --git a/new-file b/renamed-file
+  rename from new-file
+  rename to renamed-file
+  1 hunks, 1 lines changed
+  examine changes to 'new-file' and 'renamed-file'?
+  (enter ? for help) [Ynesfdaq?] y
+  
+  @@ -1,1 +1,2 @@
+   content
+  +new-content
+  record this change to 'renamed-file'?
+  (enter ? for help) [Ynesfdaq?] n
+  
+  $ hg status
+  M renamed-file
+  ? editedfile.orig
+  ? editedfile.rej
+  ? editor.sh
+  $ hg diff
+  diff -r * renamed-file (glob)
+  --- a/renamed-file	Thu Jan 01 00:00:24 1970 +0000
+  +++ b/renamed-file	Thu Jan 01 00:00:00 1970 +0000
+  @@ -1,1 +1,2 @@
+   content
+  +new-content
+
 The #if execbit block above changes the hash here on some systems
   $ hg status -A plain3
   C plain3
   $ hg tip
-  changeset:   32:* (glob)
+  changeset:   34:* (glob)
   tag:         tip
   user:        test
-  date:        Thu Jan 01 00:00:23 1970 +0000
-  summary:     moving_files
+  date:        Thu Jan 01 00:00:24 1970 +0000
+  summary:     content-rename
   
 Editing patch of newly added file
 
   $ hg update -C .
-  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cat > editor.sh << '__EOF__'
   > cat "$1"  | sed "s/first/very/g"  > tt
   > mv tt  "$1"
@@ -1737,7 +1775,7 @@
   > This is the third line
   > __EOF__
   $ hg add newfile
-  $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit -i -d '23 0' -medit-patch-new <<EOF
+  $ HGEDITOR="\"sh\" \"`pwd`/editor.sh\"" hg commit -i -d '25 0' -medit-patch-new <<EOF
   > y
   > e
   > EOF
@@ -1770,7 +1808,7 @@
   $ cd folder
   $ echo "foo" > bar
   $ hg add bar
-  $ hg commit -i -d '23 0' -mnewfilesubdir  <<EOF
+  $ hg commit -i -d '26 0' -mnewfilesubdir  <<EOF
   > y
   > y
   > EOF
@@ -1786,15 +1824,15 @@
   
 The #if execbit block above changes the hashes here on some systems
   $ hg tip -p
-  changeset:   34:* (glob)
+  changeset:   36:* (glob)
   tag:         tip
   user:        test
-  date:        Thu Jan 01 00:00:23 1970 +0000
+  date:        Thu Jan 01 00:00:26 1970 +0000
   summary:     newfilesubdir
   
   diff -r * -r * folder/bar (glob)
   --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
-  +++ b/folder/bar	Thu Jan 01 00:00:23 1970 +0000
+  +++ b/folder/bar	Thu Jan 01 00:00:26 1970 +0000
   @@ -0,0 +1,1 @@
   +foo