nwjs/nw.js · critical · Exception

%d patches failed to apply. Your build will not be correct.

Error message

%d patches failed to apply. Your build will not be correct.

What it means

Raised by apply_patch_config() in tools/patcher.py after the loop over patches completes, when results['fail'] > 0. Each patch is applied via git_apply_patch_file; if any return 'fail', the build is considered incorrect because the Chromium source tree will be in a partially-patched state. The exception halts the build to prevent shipping a broken binary.

Source

Thrown at tools/patcher.py:95

    if dopatch:
      result = apply_patch_file(patch_file, patch['path']
                                if 'path' in patch else None)
      results[result] += 1

      if 'note' in patch:
        write_note('NOTE', patch['note'])
    else:
      results['skip'] += 1

  sys.stdout.write('\n%d patches total (%d applied, %d skipped, %d failed)\n' % \
      (len(patches), results['apply'], results['skip'], results['fail']))

  if results['fail'] > 0:
    sys.stdout.write('\n')
    write_note('ERROR',
               '%d patches failed to apply. Your build will not be correct.' %
               results['fail'])
    raise Exception(
        '%d patches failed to apply. Your build will not be correct.' %
        results['fail'])


# Parse command-line options.
disc = """
This utility applies patch files.
"""

parser = OptionParser(description=disc)
parser.add_option(
    '--patch-file', dest='patchfile', metavar='FILE', help='patch source file')
parser.add_option(
    '--patch-dir',
    dest='patchdir',
    metavar='DIR',
    help='patch target directory')
# NWJS: Path of config file has been hard-coded in this script, so this option

View on GitHub (pinned to e15da848e9)

Solutions

Inspect the per-patch 'This patch failed to apply' NOTE output above the summary to identify which patch(es) failed.
Rebase the offending .patch file against the current Chromium source: regenerate with git diff or manually fix context lines.
Reset the source tree to a clean state (git checkout . in the Chromium src dir) and re-run patcher to rule out a half-patched tree.
Verify the Chromium revision matches what the NW.js patches target (check DEPS / the pinned commit).

Defensive patterns

Strategy: try-catch

Validate before calling

import subprocess

def patch_applies_cleanly(patch_path, src_dir):
    result = subprocess.run(['git', 'apply', '--check', patch_path], cwd=src_dir)
    return result.returncode == 0

Try / catch

try:
    apply_patch_config()
except Exception as e:
    if 'patches failed to apply' in str(e):
        # reset tree and rebase patches against current Chromium rev
        subprocess.run(['git', 'checkout', '.'], cwd=src_dir)
        raise SystemExit('Rebase failed patches against the current Chromium revision, then rebuild.')
    raise

Prevention

Keep the Chromium revision in sync with what the NW.js patches target (check DEPS).
Reset the source tree to a clean state before re-running patcher to avoid half-patched conflicts.
Re-generate stale .patch files with git diff when rebasing onto a new Chromium version.
Watch line-ending settings (core.autocrlf) that can break git apply.

When it happens

Trigger: A patch in patch.cfg no longer applies cleanly against the checked-out Chromium revision (context mismatch, already-applied hunk, conflicting upstream change); a patch file referenced by patch.cfg is missing from patch/patches/; line-ending or whitespace drift causing git apply to reject a hunk.

Common situations: Upgrading the Chromium revision without rebasing the NW.js patches; switching OS line endings (CRLF/LF) that confuse git apply; partial previous run leaving the tree half-patched so re-application conflicts; stale patch files after a branch switch.

Related errors

AI-assisted analysis of nwjs/nw.js@e15da848e9 (2026-08-13). Data as JSON: /api/errors/2d88ce50717d5f86. Report an issue: GitHub.