Add explicit allRefs = true; argument to fetchGit

Sometimes it's necessary to fetch a git repository at a revision and
it's unknown which ref contains the revision in question. An example
would be a Cargo.lock which only provides the URL and the revision when
using a git repository as build input.

However it's considered a bad practice to perform a full checkout of a
repository since this may take a lot of time and can eat up a lot of
disk space. This patch makes a full checkout explicit by adding an
`allRefs` argument to `builtins.fetchGit` which fetches all refs if
explicitly set to true.

Closes #2409
This commit is contained in:
Maximilian Bosch 2020-07-17 20:34:57 +02:00
parent 629af83b2d
commit 2857b1baaf
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GPG key ID: 091DBF4D1FC46B8E

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@ -59,12 +59,13 @@ struct GitInputScheme : InputScheme
if (maybeGetStrAttr(attrs, "type") != "git") return {};
for (auto & [name, value] : attrs)
if (name != "type" && name != "url" && name != "ref" && name != "rev" && name != "shallow" && name != "submodules" && name != "lastModified" && name != "revCount" && name != "narHash")
if (name != "type" && name != "url" && name != "ref" && name != "rev" && name != "shallow" && name != "submodules" && name != "lastModified" && name != "revCount" && name != "narHash" && name != "allRefs")
throw Error("unsupported Git input attribute '%s'", name);
parseURL(getStrAttr(attrs, "url"));
maybeGetBoolAttr(attrs, "shallow");
maybeGetBoolAttr(attrs, "submodules");
maybeGetBoolAttr(attrs, "allRefs");
if (auto ref = maybeGetStrAttr(attrs, "ref")) {
if (std::regex_search(*ref, badGitRefRegex))
@ -169,10 +170,12 @@ struct GitInputScheme : InputScheme
bool shallow = maybeGetBoolAttr(input.attrs, "shallow").value_or(false);
bool submodules = maybeGetBoolAttr(input.attrs, "submodules").value_or(false);
bool allRefs = maybeGetBoolAttr(input.attrs, "allRefs").value_or(false);
std::string cacheType = "git";
if (shallow) cacheType += "-shallow";
if (submodules) cacheType += "-submodules";
if (allRefs) cacheType += "-all-refs";
auto getImmutableAttrs = [&]()
{
@ -337,6 +340,9 @@ struct GitInputScheme : InputScheme
throw;
}
}
} else {
if (allRefs) {
doFetch = true;
} else {
/* If the local ref is older than tarball-ttl seconds, do a
git fetch to update the local ref to the remote ref. */
@ -344,6 +350,7 @@ struct GitInputScheme : InputScheme
doFetch = stat(localRefFile.c_str(), &st) != 0 ||
(uint64_t) st.st_mtime + settings.tarballTtl <= (uint64_t) now;
}
}
if (doFetch) {
Activity act(*logger, lvlTalkative, actUnknown, fmt("fetching Git repository '%s'", actualUrl));
@ -352,7 +359,9 @@ struct GitInputScheme : InputScheme
// we're using --quiet for now. Should process its stderr.
try {
auto ref = input.getRef();
auto fetchRef = ref->compare(0, 5, "refs/") == 0
auto fetchRef = allRefs
? "refs/*"
: ref->compare(0, 5, "refs/") == 0
? *ref
: "refs/heads/" + *ref;
runProgram("git", true, { "-C", repoDir, "fetch", "--quiet", "--force", "--", actualUrl, fmt("%s:%s", fetchRef, fetchRef) });