discover: manage go.* files

The discovery repository can be in an incosistent state
after a build. By restoring the go.* files, we ensure a stable
start point.

Add automatic removal of go.sum files from git-fetched
dependencies in vcs_cache during do_create_module_cache.
This prevents checksum mismatch errors caused by stale
go.sum files in dependencies having different checksums
than the git-sourced modules.

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

2 files changed, 27 insertions, 0 deletions

diff --git a/classes/go-mod-discovery.bbclass b/classes/go-mod-discovery.bbclass
index 05265c20..d57a7d38 100644
--- a/classes/go-mod-discovery.bbclass
+++ b/classes/go-mod-discovery.bbclass
@@ -184,9 +184,20 @@ Hint: Set GO_MOD_DISCOVERY_SRCDIR to the directory containing go.mod"
     echo "LDFLAGS:       ${GO_MOD_DISCOVERY_LDFLAGS}"
     echo ""
 
+    # Restore original go.sum from git if it was modified by do_create_module_cache
+    # The build task rewrites go.sum with git-based checksums, but discovery needs
+    # the original proxy-based checksums to download from proxy.golang.org
+    if git -C "${GO_MOD_DISCOVERY_SRCDIR}" diff --quiet go.sum 2>/dev/null; then
+        echo "go.sum is clean"
+    else
+        echo "Restoring original go.sum from git (was modified by previous build)..."
+        git -C "${GO_MOD_DISCOVERY_SRCDIR}" checkout go.sum
+    fi
+
     # Use native go binary
     GO_NATIVE="${STAGING_DIR_NATIVE}${bindir_native}/go"
 
+    echo ""
     echo "Running: go build (to discover all modules)..."
 
     BUILD_CMD="${GO_NATIVE} build -v -trimpath"
@@ -341,9 +352,13 @@ Add to your recipe: GO_MOD_DISCOVERY_GIT_REPO = \"https://github.com/...\"
 Or run 'bitbake ${PN} -c show_upgrade_commands' to see manual options."
     fi
 
+    # CRITICAL: Change to source directory so oe-go-mod-fetcher.py can find go.mod/go.sum
+    cd "${GO_MOD_DISCOVERY_SRCDIR}"
+
     echo "======================================================================"
     echo "GENERATING RECIPE FILES: ${PN} ${PV}"
     echo "======================================================================"
+    echo "Source dir:   ${GO_MOD_DISCOVERY_SRCDIR}"
     echo "Modules JSON: ${GO_MOD_DISCOVERY_MODULES_JSON}"
     echo "Git repo:     ${GO_MOD_DISCOVERY_GIT_REPO}"
     echo "Git ref:      ${GO_MOD_DISCOVERY_GIT_REF}"
diff --git a/classes/go-mod-vcs.bbclass b/classes/go-mod-vcs.bbclass
index 26c8c7f3..cf583462 100644
--- a/classes/go-mod-vcs.bbclass
+++ b/classes/go-mod-vcs.bbclass
@@ -797,6 +797,18 @@ python do_create_module_cache() {
     workdir = Path(d.getVar('WORKDIR'))
     modules_data = json.loads(d.getVar('GO_MODULE_CACHE_DATA'))
 
+    # Remove go.sum files from git-fetched dependencies to prevent checksum conflicts
+    # The module checksums from git sources differ from the proxy checksums, and stale
+    # go.sum files in dependencies can cause "checksum mismatch" errors during build
+    vcs_cache_dir = workdir / "sources" / "vcs_cache"
+    if vcs_cache_dir.exists():
+        import subprocess
+        result = subprocess.run(
+            ['find', str(vcs_cache_dir), '-name', 'go.sum', '-delete'],
+            capture_output=True, text=True
+        )
+        bb.debug(1, "Removed go.sum files from vcs_cache to prevent checksum conflicts")
+
     bb.note(f"Building module cache for {len(modules_data)} modules")
 
     # Track results from processing