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_parse_json_field - use explicit keyword arguments
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Addressing review comment
#1376 (comment)
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@aherrmann
aherrmann committed Jul 2, 2020
1 parent 0505fb2 commit ec7380c
Showing 1 changed file with 137 additions and 47 deletions.
184 changes: 137 additions & 47 deletions haskell/cabal.bzl
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Expand Up @@ -892,7 +892,7 @@ def _get_components(components, package):
"""
return components.get(package, _default_components.get(package, struct(lib = True, exe = [])))

def _parse_json_field(json, field, ty, fmt):
def _parse_json_field(json, field, ty, errmsg):
"""Read and type-check a field from a JSON object.
Invokes `fail` on error.
Expand All @@ -901,16 +901,16 @@ def _parse_json_field(json, field, ty, fmt):
json: dict, The parsed JSON object.
field: string, The name of the field.
ty: string, The expected type of the field.
fmt: string, Error message format string. E.g. `Error: {error}`.
errmsg: string, Error message format string. E.g. `Error: {error}`.
Returns:
The value of the field.
"""
if not field in json:
fail(fmt.format(error = "Missing field '{field}'.".format(field = field)))
fail(errmsg.format(error = "Missing field '{field}'.".format(field = field)))
actual_ty = type(json[field])
if actual_ty != ty:
fail(fmt.format(error = "Expected field '{field}' of type '{expected}', but got '{got}'.".format(
fail(errmsg.format(error = "Expected field '{field}' of type '{expected}', but got '{got}'.".format(
field = field,
expected = ty,
got = actual_ty,
Expand Down Expand Up @@ -942,53 +942,53 @@ def _parse_package_spec(package_spec):
location["type"] = "core"
else:
location_type = _parse_json_field(
package_spec["location"],
"type",
"string",
errmsg.format(context = "location description"),
json = package_spec["location"],
field = "type",
ty = "string",
errmsg = errmsg.format(context = "location description"),
)
if location_type == "project package":
location["type"] = "vendored"
elif location_type == "hackage":
location["type"] = location_type
url_prefix = _parse_json_field(
package_spec["location"],
"url",
"string",
errmsg.format(context = location_type + " location description"),
json = package_spec["location"],
field = "url",
ty = "string",
errmsg = errmsg.format(context = location_type + " location description"),
)
location["url"] = url_prefix + "/{name}-{version}.tar.gz".format(**parsed)
# stack does not expose sha-256, see https://github.com/commercialhaskell/stack/issues/5274

elif location_type == "archive":
location["type"] = location_type
location["url"] = _parse_json_field(
package_spec["location"],
"url",
"string",
errmsg.format(context = location_type + " location description"),
json = package_spec["location"],
field = "url",
ty = "string",
errmsg = errmsg.format(context = location_type + " location description"),
)
# stack does not yet expose sha-256, see https://github.com/commercialhaskell/stack/pull/5280

elif location_type in ["git", "hg"]:
location["type"] = location_type
location["url"] = _parse_json_field(
package_spec["location"],
"url",
"string",
errmsg.format(context = location_type + " location description"),
json = package_spec["location"],
field = "url",
ty = "string",
errmsg = errmsg.format(context = location_type + " location description"),
)
location["commit"] = _parse_json_field(
package_spec["location"],
"commit",
"string",
errmsg.format(context = location_type + " location description"),
json = package_spec["location"],
field = "commit",
ty = "string",
errmsg = errmsg.format(context = location_type + " location description"),
)
location["subdir"] = _parse_json_field(
package_spec["location"],
"subdir",
"string",
errmsg.format(context = location_type + " location description"),
json = package_spec["location"],
field = "subdir",
ty = "string",
errmsg = errmsg.format(context = location_type + " location description"),
)
else:
error = "Unexpected location type '{}'.".format(location_type)
Expand Down Expand Up @@ -1105,7 +1105,7 @@ def _pin_packages(repository_ctx, resolved):
all-cabal-hashes: URL to the current revision of all-cabal-hashes.
resolved: the `resolved` argument, extended with reproducibility information.
"""
errmsg = "Unexpected format in all-cabal-hashes: %s"
errmsg = "Unexpected format in {context}: {{error}}"

# Determine current git revision of all-cabal-hashes.
repository_ctx.download(
Expand All @@ -1114,8 +1114,18 @@ def _pin_packages(repository_ctx, resolved):
executable = False,
)
hashes_json = json_parse(repository_ctx.read("all-cabal-hashes-hackage.json"))
hashes_object = _parse_json_field(hashes_json, "object", "dict", "all-cabal-hashes hackage branch")
hashes_commit = _parse_json_field(hashes_object, "sha", "string", "all-cabal-hashes hackage branch")
hashes_object = _parse_json_field(
json = hashes_json,
field = "object",
ty = "dict",
errmsg = errmsg.format(context = "all-cabal-hashes hackage branch"),
)
hashes_commit = _parse_json_field(
json = hashes_object,
field = "sha",
ty = "string",
errmsg = errmsg.format(context = "all-cabal-hashes hackage branch"),
)
hashes_url = "https://raw.githubusercontent.com/commercialhaskell/all-cabal-hashes/" + hashes_commit

resolved = dict(**resolved)
Expand All @@ -1131,14 +1141,29 @@ def _pin_packages(repository_ctx, resolved):
executable = False,
)
json = json_parse(repository_ctx.read("{name}-{version}.json".format(**spec)))
hashes = _parse_json_field(json, "package-hashes", "dict", errmsg)
hashes = _parse_json_field(
json = json,
field = "package-hashes",
ty = "dict",
errmsg = errmsg.format(context = "all-cabal-hashes package description"),
)

# Cabal file downloads are not reproducible due to Hackage revisions.
# We pin the git revision of all-cabal-hashes and sha256 of the Cabal file.
cabal_url = "{url}/{name}/{version}/{name}.cabal".format(url = hashes_url, **spec)
spec["pinned"] = {
"url": _parse_json_field(json, "package-locations", "list", errmsg),
"sha256": _parse_json_field(hashes, "SHA256", "string", errmsg),
"url": _parse_json_field(
json = json,
field = "package-locations",
ty = "list",
errmsg = errmsg.format(context = "all-cabal-hashes package description"),
),
"sha256": _parse_json_field(
hashes,
"SHA256",
"string",
errmsg = errmsg.format(context = "all-cabal-hashes package hashes"),
),
"cabal-sha256": repository_ctx.download(
cabal_url,
output = "{name}-{version}.cabal".format(**spec),
Expand Down Expand Up @@ -1402,9 +1427,24 @@ Try to regenerate it by running the following command:
fail(errmsg.format(error = "Failed to parse JSON."))

# Read snapshot.json data and validate required fields.
expected_checksum = _parse_json_field(pinned, "__GENERATED_FILE_DO_NOT_MODIFY_MANUALLY", "int", errmsg)
all_cabal_hashes = _parse_json_field(pinned, "all-cabal-hashes", "string", errmsg)
raw_resolved = _parse_json_field(pinned, "resolved", "dict", errmsg)
expected_checksum = _parse_json_field(
json = pinned,
field = "__GENERATED_FILE_DO_NOT_MODIFY_MANUALLY",
ty = "int",
errmsg = errmsg,
)
all_cabal_hashes = _parse_json_field(
json = pinned,
field = "all-cabal-hashes",
ty = "string",
errmsg = errmsg,
)
raw_resolved = _parse_json_field(
json = pinned,
field = "resolved",
ty = "dict",
errmsg = errmsg,
)
resolved = {}
for name in sorted(raw_resolved.keys()):
raw_spec = raw_resolved[name]
Expand All @@ -1413,36 +1453,86 @@ Try to regenerate it by running the following command:
for (field, ty) in [("name", "string"), ("version", "string"), ("dependencies", "list")]
}

raw_location = _parse_json_field(raw_spec, "location", "dict", errmsg)
location_type = _parse_json_field(raw_location, "type", "string", errmsg)
raw_location = _parse_json_field(
json = raw_spec,
field = "location",
ty = "dict",
errmsg = errmsg,
)
location_type = _parse_json_field(
json = raw_location,
field = "type",
ty = "string",
errmsg = errmsg,
)
if location_type in ["core", "vendored"]:
spec["location"] = {"type": location_type}
elif location_type in ["hackage", "archive"]:
spec["location"] = {
"type": location_type,
"url": _parse_json_field(raw_location, "url", "string", errmsg),
"url": _parse_json_field(
json = raw_location,
field = "url",
ty = "string",
errmsg = errmsg,
),
}
elif location_type in ["git", "hg"]:
spec["location"] = {
"type": location_type,
"url": _parse_json_field(raw_location, "url", "string", errmsg),
"commit": _parse_json_field(raw_location, "commit", "string", errmsg),
"subdir": _parse_json_field(raw_location, "subdir", "string", errmsg),
"url": _parse_json_field(
json = raw_location,
field = "url",
ty = "string",
errmsg = errmsg,
),
"commit": _parse_json_field(
json = raw_location,
field = "commit",
ty = "string",
errmsg = errmsg,
),
"subdir": _parse_json_field(
json = raw_location,
field = "subdir",
ty = "string",
errmsg = errmsg,
),
}
else:
fail(errmsg.format(error = "Unknown location type '{}'.".format(location_type)))

if location_type == "hackage":
raw_pinned = _parse_json_field(raw_spec, "pinned", "dict", errmsg)
raw_pinned = _parse_json_field(
json = raw_spec,
field = "pinned",
ty = "dict",
errmsg = errmsg,
)
spec["pinned"] = {
field: _parse_json_field(raw_pinned, field, ty, errmsg)
for (field, ty) in [("url", "list"), ("sha256", "string"), ("cabal-sha256", "string")]
}
elif location_type == "archive":
raw_pinned = _parse_json_field(raw_spec, "pinned", "dict", errmsg)
raw_pinned = _parse_json_field(
json = raw_spec,
field = "pinned",
ty = "dict",
errmsg = errmsg,
)
spec["pinned"] = {
"sha256": _parse_json_field(raw_pinned, "sha256", "string", errmsg),
"strip-prefix": _parse_json_field(raw_pinned, "strip-prefix", "string", errmsg),
"sha256": _parse_json_field(
json = raw_pinned,
field = "sha256",
ty = "string",
errmsg = errmsg,
),
"strip-prefix": _parse_json_field(
json = raw_pinned,
field = "strip-prefix",
ty = "string",
errmsg = errmsg,
),
}

resolved[name] = spec
Expand Down

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