From 24e7398e225fc288d0a299fc6cd77fcf1539835c Mon Sep 17 00:00:00 2001
From: Klaus Aehlig <klaus.aehlig@huawei.com>
Date: Mon, 16 Jan 2023 16:55:41 +0100
Subject: just-mr fetch: fix overwriting distfiles

Both, the python script as well as the compiled variant of just-mr
fetch try to overwrite already existing distfiles in the distdir.
While it is unclear if overwriting existing distfiles or not
copying to distdir if a file with that name already exists is the
better behaviour, we at least should not error out, as the compiled
just-mr currently does as it sets permission to 444 and hence cannot
overwrite later; fix this by addwing owner write permissions before
overwriting.
---
 src/other_tools/ops_maps/repo_fetch_map.cpp | 30 +++++++++++++++++++++--------
 test/end-to-end/just-mr/fetch.sh            |  6 ++++++
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/src/other_tools/ops_maps/repo_fetch_map.cpp b/src/other_tools/ops_maps/repo_fetch_map.cpp
index 274124a1..e0ff438e 100644
--- a/src/other_tools/ops_maps/repo_fetch_map.cpp
+++ b/src/other_tools/ops_maps/repo_fetch_map.cpp
@@ -51,13 +51,20 @@ auto CreateRepoFetchMap(gsl::not_null<ContentCASMap*> const& content_cas_map,
                     auto content_path =
                         casf.BlobPath(ArtifactDigest(content, 0, false));
                     if (content_path) {
-                        if (not FileSystemManager::CopyFile(
-                                *content_path, fetch_dir / distfile)) {
+                        auto target_name = fetch_dir / distfile;
+                        if (FileSystemManager::Exists(target_name)) {
+                            std::filesystem::permissions(
+                                target_name,
+                                std::filesystem::perms::owner_write,
+                                std::filesystem::perm_options::add);
+                        }
+                        if (not FileSystemManager::CopyFile(*content_path,
+                                                            target_name)) {
                             (*logger)(fmt::format(
                                           "Failed to copy content {} from CAS "
-                                          "into fetch directory {}",
+                                          "to {}",
                                           content,
-                                          fetch_dir.string()),
+                                          target_name.string()),
                                       /*fatal=*/true);
                             return;
                         }
@@ -87,12 +94,19 @@ auto CreateRepoFetchMap(gsl::not_null<ContentCASMap*> const& content_cas_map,
             auto content_path =
                 casf.BlobPath(ArtifactDigest(key.archive.content, 0, false));
             if (content_path) {
+                auto target_name = fetch_dir / distfile;
+                if (FileSystemManager::Exists(target_name)) {
+                    std::filesystem::permissions(
+                        target_name,
+                        std::filesystem::perms::owner_write,
+                        std::filesystem::perm_options::add);
+                }
                 if (not FileSystemManager::CopyFile(*content_path,
-                                                    fetch_dir / distfile)) {
+                                                    target_name)) {
                     (*logger)(fmt::format("Failed to copy content {} from CAS "
-                                          "into fetch directory {}",
+                                          "to {}",
                                           key.archive.content,
-                                          fetch_dir.string()),
+                                          target_name.string()),
                               /*fatal=*/true);
                     return;
                 }
@@ -108,4 +122,4 @@ auto CreateRepoFetchMap(gsl::not_null<ContentCASMap*> const& content_cas_map,
         }
     };
     return AsyncMapConsumer<ArchiveRepoInfo, bool>(fetch_repo, jobs);
-}
\ No newline at end of file
+}
diff --git a/test/end-to-end/just-mr/fetch.sh b/test/end-to-end/just-mr/fetch.sh
index 8009f151..8bd78929 100644
--- a/test/end-to-end/just-mr/fetch.sh
+++ b/test/end-to-end/just-mr/fetch.sh
@@ -67,4 +67,10 @@ newfoocontent=$(git hash-object "${DISTDIR}/foo-1.2.3.tar")
 echo "Foo archive has now content ${newfoocontent}"
 test "${newfoocontent}" = "${foocontent}"
 
+# Verify that fetching accepts distfiles already present
+"${JUST_MR}" --local-build-root "${LBR}" --distdir "${DISTDIR}" fetch 2>&1
+newfoocontent=$(git hash-object "${DISTDIR}/foo-1.2.3.tar")
+echo "Foo archive has now content ${newfoocontent}"
+test "${newfoocontent}" = "${foocontent}"
+
 echo OK
-- 
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