dotnet/aspnetcore · error · ValueError

Invalid Debian version format: {version}

Error message

Invalid Debian version format: {version}

What it means

parse_debian_version applies the regex ^(?:(\d+):)?([^-]+)(?:-(.+))?$ to a version string and raises ValueError if it does not match. This parser underpins compare_debian_versions used to pick the highest version of each package from the index. Debian versions are normally epoch:upstream-revision, but malformed entries (empty string, version starting with '-', containing only a hyphen, etc.) break the regex.

Source

Thrown at eng/common/cross/install-debs.py:160

def parse_release_file(content, path):
    """Parses the Release file and returns sha256 checksum of the specified path."""

    # data looks like this:
    # <checksum>  <size>  <path>
    matches = re.findall(r'^ (\S*) +(\S*) +(\S*)$', content, re.MULTILINE)

    for entry in matches:
        # the file has both md5 and sha256 checksums, we want sha256 which has a length of 64
        if entry[2] == path and len(entry[0]) == 64:
            return entry[0]

    raise Exception(f"Could not find checksum for {path} in Release file.")

def parse_debian_version(version):
    """Parse a Debian package version into epoch, upstream version, and revision."""
    match = re.match(r'^(?:(\d+):)?([^-]+)(?:-(.+))?$', version)
    if not match:
        raise ValueError(f"Invalid Debian version format: {version}")
    epoch, upstream, revision = match.groups()
    return int(epoch) if epoch else 0, upstream, revision or ""

def compare_upstream_version(v1, v2):
    """Compare upstream or revision parts using Debian rules."""
    def tokenize(version):
        tokens = re.split(r'([0-9]+|[A-Za-z]+)', version)
        return [int(x) if x.isdigit() else x for x in tokens if x]

    tokens1 = tokenize(v1)
    tokens2 = tokenize(v2)

    for token1, token2 in zip(tokens1, tokens2):
        if type(token1) == type(token2):
            if token1 != token2:
                return (token1 > token2) - (token1 < token2)
        else:
            return -1 if isinstance(token1, str) else 1

View on GitHub (pinned to 294cab2f9b)

Solutions

1. Re-download the Packages.gz from a clean mirror — corruption during fetch is the usual cause.
2. Verify the --mirror and --suite produce a well-formed Packages.gz (open it and grep for 'Version:' lines).
3. If a single malformed package is to blame, exclude it from the requested package list or filter it before parse_package_index.
4. Inspect the offending version string in the exception message to determine whether it is empty, hyphen-only, or otherwise non-Debian.

Example fix

# before — corrupt Packages.gz from a flaky mirror
python3 install-debs.py --mirror http://bad-mirror/debian --suite sid ...
# ValueError: Invalid Debian version format: 

# after
python3 install-debs.py --mirror http://deb.debian.org/debian --suite sid ...

# Pre-validate version strings before feeding them to compare_debian_versions
import re
DEB_VERSION_RE = re.compile(r'^(?:(\d+):)?([^-]+)(?:-(.+))?$')
def is_valid_debian_version(v: str) -> bool:
    return bool(v) and bool(DEB_VERSION_RE.match(v))

for name, info in packages.items():
    v = info.get('Version')
    if not is_valid_debian_version(v):
        print(f'Skipping {name}: malformed Version {v!r}')
        continue

import re
_DEB_VERSION_RE = re.compile(r'^(?:(\d+):)?([^-]+)(?:-(.+))?$')
def is_valid_debian_version(v: object) -> bool:
    return isinstance(v, str) and bool(v) and bool(_DEB_VERSION_RE.match(v))

try:
    epoch, upstream, revision = parse_debian_version(version)
except ValueError as e:
    if 'Invalid Debian version format' in str(e):
        print(f'Skipping entry with malformed version {version!r}; re-download Packages.gz')
        continue
    raise

When it happens

Trigger: parse_package_index extracts Version fields from Packages.gz entries and calls compare_debian_versions whenever a package name already has a recorded version. If a mirror's Packages.gz contains a corrupt/empty Version field, the regex fails and ValueError is raised. Also triggered by manually feeding a non-Debian version string into the comparator.

Common situations: Corrupt or partial Packages.gz download that produced garbage Version fields; a mirror shipping a test/development package with a non-conformant version; an upstream package whose versioning violates Debian policy.

Related errors

• SHA256 mismatch for {url}: expected {checksum}, got {sha256}
• Failed to download {url}, Status Code: {response.status}
• Failed to download {url} after {max_retries} attempts.
• SHA256 mismatch for {path}: expected {packages_sha}, got {sh
• Signature verification failed: {result.stderr.decode('utf-8'

AI-assisted analysis of dotnet/aspnetcore@294cab2f9b (2026-08-06). Data as JSON: /api/errors/ea7261baa6c9cec3. Report an issue: GitHub.