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Test sccache with temp copy #124074

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c032b94
Test sccache with temp copy
agocke Feb 6, 2026
acc3583
Use portable binary
agocke Feb 6, 2026
2fc886e
Print sccache stats before running
agocke Feb 6, 2026
709d5dd
Apply suggestion from @Copilot
agocke Feb 6, 2026
f53e79d
Use anonymous acces
agocke Feb 7, 2026
e22b6fa
Typo
agocke Feb 7, 2026
7e67bc9
No creds
agocke Feb 7, 2026
a36ccd1
Use sccache with anon backend support
agocke Feb 7, 2026
b8aea3b
Also print stats at end
agocke Feb 7, 2026
3ba5ec6
Remove everything except a single job for testing
agocke Feb 7, 2026
b8c56ec
Add logging
agocke Feb 7, 2026
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19 changes: 19 additions & 0 deletions eng/build.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -584,6 +584,21 @@ arguments+=("-clp:ForceNoAlign")

initDistroRid "$os" "$arch" "$crossBuild"

# Enable sccache for linux-x64 builds if the binary is present in the repo root.
if [[ "$os" == "linux" && "$arch" == "x64" && -f "$scriptroot/../sccache" ]]; then
export PATH="$scriptroot/..:$PATH"
Comment on lines +588 to +589
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Copilot AI Feb 7, 2026

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The enablement check uses -f "$scriptroot/../sccache", but that doesn't guarantee the file is executable. If the file exists without execute permissions, the later sccache -s/compiler launcher will fail and stop the build. Prefer checking -x (and/or verifying command -v sccache after updating PATH) before enabling.

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Copilot AI Feb 7, 2026

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Prepending the repo root to PATH can unintentionally shadow system tools if a same-named executable exists in the repo (now or in the future), making builds harder to reason about. A safer pattern is to invoke sccache via an explicit absolute path and/or add only a dedicated tools directory to PATH.

Suggested change
export PATH="$scriptroot/..:$PATH"
export PATH="$PATH:$scriptroot/.."

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export USE_SCCACHE=true
export SCCACHE_AZURE_BLOB_CONTAINER=runtime-cache
export SCCACHE_AZURE_CONNECTION_STRING="BlobEndpoint=https://runsccache.blob.core.windows.net"
export SCCACHE_AZURE_NO_CREDENTIALS=true
mkdir -p "$scriptroot/../artifacts/log"
export SCCACHE_ERROR_LOG="$scriptroot/../artifacts/log/sccache_debug.log"
export SCCACHE_LOG=debug
sccache --start-server
echo "sccache enabled for linux-x64 build"
sccache -s
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The condition only checks -f "$scriptroot/../sccache", but the code later executes sccache as a command name. If the file exists but isn’t executable (or isn’t found via PATH), this will fail. Prefer checking -x and executing "$scriptroot/../sccache" (or ensuring PATH is updated before any invocation).

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Copilot AI Feb 7, 2026

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Because eng/build.sh runs with set -e, a failure from sccache -s (e.g., server startup failure, unsupported backend, transient network issue) will abort the entire build even though this is just a diagnostic step. Consider making the stats call best-effort (or gating it behind an explicit opt-in) so cache issues don't fail the build.

Suggested change
sccache -s
sccache -s || echo "sccache stats are unavailable; continuing without cache stats"

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Comment on lines 587 to 599
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The guard only checks -f "$scriptroot/../sccache", but with set -e the build will still fail later if that file isn't executable or can't be invoked. It should check that the binary is executable (and ideally invoke it via its full path) before enabling USE_SCCACHE/modifying PATH.

Suggested change
# Enable sccache for linux-x64 builds if the binary is present in the repo root.
if [[ "$os" == "linux" && "$arch" == "x64" && -f "$scriptroot/../sccache" ]]; then
export PATH="$scriptroot/..:$PATH"
export USE_SCCACHE=true
export SCCACHE_AZURE_BLOB_CONTAINER=runtime-cache
export SCCACHE_AZURE_CONNECTION_STRING="BlobEndpoint=https://runsccache.blob.core.windows.net"
export SCCACHE_AZURE_NO_CREDENTIALS=true
echo "sccache enabled for linux-x64 build"
sccache -s
# Enable sccache for linux-x64 builds if the binary is present and executable in the repo root.
if [[ "$os" == "linux" && "$arch" == "x64" && -f "$scriptroot/../sccache" && -x "$scriptroot/../sccache" ]]; then
export PATH="$scriptroot/..:$PATH"
export USE_SCCACHE=true
export SCCACHE_AZURE_BLOB_CONTAINER=runtime-cache
export SCCACHE_AZURE_CONNECTION_STRING="BlobEndpoint=https://runsccache.blob.core.windows.net"
export SCCACHE_AZURE_NO_CREDENTIALS=true
echo "sccache enabled for linux-x64 build"
"$scriptroot/../sccache" -s

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Comment on lines +588 to +599
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The sccache presence check uses -f but the script immediately executes sccache. If the file exists but isn’t executable (or is the wrong binary), the build will fail (this script runs with set -e). Prefer checking -x and/or validating that invoking sccache --version succeeds before enabling it.

Suggested change
if [[ "$os" == "linux" && "$arch" == "x64" && -f "$scriptroot/../sccache" ]]; then
export PATH="$scriptroot/..:$PATH"
export USE_SCCACHE=true
export SCCACHE_AZURE_BLOB_CONTAINER=runtime-cache
export SCCACHE_AZURE_CONNECTION_STRING="BlobEndpoint=https://runsccache.blob.core.windows.net"
export SCCACHE_AZURE_NO_CREDENTIALS=true
mkdir -p "$scriptroot/../artifacts/log"
export SCCACHE_ERROR_LOG="$scriptroot/../artifacts/log/sccache_debug.log"
export SCCACHE_LOG=debug
sccache --start-server
echo "sccache enabled for linux-x64 build"
sccache -s
if [[ "$os" == "linux" && "$arch" == "x64" && -x "$scriptroot/../sccache" ]]; then
if "$scriptroot/../sccache" --version >/dev/null 2>&1; then
export PATH="$scriptroot/..:$PATH"
export USE_SCCACHE=true
export SCCACHE_AZURE_BLOB_CONTAINER=runtime-cache
export SCCACHE_AZURE_CONNECTION_STRING="BlobEndpoint=https://runsccache.blob.core.windows.net"
export SCCACHE_AZURE_NO_CREDENTIALS=true
mkdir -p "$scriptroot/../artifacts/log"
export SCCACHE_ERROR_LOG="$scriptroot/../artifacts/log/sccache_debug.log"
export SCCACHE_LOG=debug
"$scriptroot/../sccache" --start-server
echo "sccache enabled for linux-x64 build"
"$scriptroot/../sccache" -s
fi

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fi
Comment on lines 587 to 600
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Copilot AI Feb 6, 2026

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The sccache integration only affects CoreCLR builds because only src/coreclr/build-runtime.sh checks the USE_SCCACHE environment variable. Other native components (Mono, native libs, host/corehost) do not currently respect this setting and will not use sccache even when enabled. Consider documenting this limitation in the comment, or adding USE_SCCACHE support to other native build scripts if caching is desired for those components as well.

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Comment on lines +597 to +600
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sccache --start-server and sccache -s will hard-fail the entire build if sccache can’t start or the remote backend isn’t reachable (because eng/build.sh runs with set -e). If sccache is intended to be a best-effort accelerator, wrap these invocations so failures don’t abort the build, and only emit stats when the server is actually running.

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# Disable targeting pack caching as we reference a partially constructed targeting pack and update it later.
# The later changes are ignored when using the cache.
export DOTNETSDK_ALLOW_TARGETING_PACK_CACHING=0
Expand Down Expand Up @@ -621,3 +636,7 @@ if [[ "$bootstrap" == "1" ]]; then
fi

"$scriptroot/common/build.sh" ${arguments[@]+"${arguments[@]}"}

if [[ "$os" == "linux" && "$arch" == "x64" && -f "$scriptroot/../sccache" ]]; then
sccache -s
fi
Comment on lines +640 to +642
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The same linux/x64 + sccache-present condition is duplicated here and above. Consider factoring it into a single helper/variable to avoid future drift (e.g., if the condition or path changes in one place but not the other).

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