ci: let apt fail over between mirrors instead of hanging

The hosted Ubuntu x64 runners read the archive through
mirror+file:/etc/apt/apt-mirrors.txt. With Acquire::Retries above 0
(including the apt default of 3), a failover from a dead first entry
of that list (connection refused, DNS failure or a stalled host) to
the next entry goes idle: apt-get fetches a few InRelease files from
the second mirror and then waits until the step timeout. With
Acquire::Retries=0 the same failover completes. Seen on noble
(apt 2.8.3) and jammy (apt 2.4.14).

Every apt step this branch hardened now picks the retry count at
runtime, applied to both update and install: 0 when the runner has the
mirror list (moving to the next mirror is the retry), 3 otherwise
(arm64 runners and any host with plain sources keep their retries).
--error-on=any, the http and https timeouts and the step timeouts are
unchanged.

Proof: the step text extracted from the edited _build.yml (update plus
install of zlib1g-dev), run under bash -e in ubuntu:24.04 and
ubuntu:22.04 containers with runner-shaped mirror lists:
- first mirror refused: exit 0 in 8 s / 9 s, every index and deb
  fetched from the second mirror
- first mirror stalled (192.0.2.1): exit 0 in 68 s / 69 s, one 30 s
  timeout each for update and install, then the second mirror
- healthy first mirror: exit 0 in 7 s / 9 s
- no mirror list, plain sources: the prefix keeps Retries=3, exit 0
  in 8 s / 7 s
- every mirror dead: update exits 100 in under 1 s, install skipped
- revert check, the previous step text with a dead first mirror
  (refused or stalled): idle with no Packages index at the 180 s cap
  on both releases

Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>

.github/workflows/_build.yml

@@ -67,7 +67,7 @@ jobs:
       - name: Install deps (Ubuntu)
         if: startsWith(matrix.os, 'ubuntu')
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
 
       - uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
         with:
@@ -252,7 +252,7 @@ jobs:
 
       - name: Install deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
 
       - uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
         with:

.github/workflows/_lint.yml

@@ -38,15 +38,15 @@ jobs:
 
       - name: Install build deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev cmake
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev cmake
 
       - name: Install LLVM 20
         timeout-minutes: 10
         run: |
           wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
           echo "deb http://apt.llvm.org/noble/ llvm-toolchain-noble-20 main" | sudo tee /etc/apt/sources.list.d/llvm-20.list
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang-format-20
+          APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update
+          sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang-format-20
 
       - uses: actions/cache@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
         id: cppcheck-cache
@@ -84,15 +84,15 @@ jobs:
 
       - name: Install build deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
 
       - name: Install LLVM 21 (pinned analyzer toolchain)
         timeout-minutes: 10
         run: |
           wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
           echo "deb http://apt.llvm.org/noble/ llvm-toolchain-noble-21 main" | sudo tee /etc/apt/sources.list.d/llvm-21.list
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang-tidy-21
+          APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update
+          sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang-tidy-21
 
       - name: Memory-analyzer gate
         run: scripts/ci/lint-mem.sh clang-tidy-21

.github/workflows/_memwaste.yml

@@ -38,7 +38,7 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Install deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 clang llvm
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 clang llvm
       - name: Event lane on this repository
         run: |
           # `cmd | tee` reports TEE's status: without this a failing lane
@@ -68,7 +68,7 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Install deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 clang llvm
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 clang llvm
       - name: CPU scaling lane (src/ at 2x against 4x)
         # Report-only: the script exits 1 when it flags a super-linear function.
         continue-on-error: true
@@ -96,7 +96,7 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Install deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 clang llvm
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 clang llvm
       - name: Access lane on this repository
         run: |
           # `cmd | tee` reports TEE's status: without this a failing lane

.github/workflows/_smoke.yml

@@ -146,7 +146,7 @@ jobs:
         if: startsWith(matrix.os, 'ubuntu')
         timeout-minutes: 10
         run: |
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update -qq && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y -qq clamav > /dev/null 2>&1
+          APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update -qq && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y -qq clamav > /dev/null 2>&1
           # apt auto-starts the clamav-freshclam daemon, which holds a lock on
           # freshclam's log/db; stop it so the manual freshclam below can run
           # (else: "Failed to lock the log file ... Resource temporarily unavailable").

.github/workflows/_soak.yml

@@ -67,7 +67,7 @@ jobs:
       - name: Install deps (Linux)
         if: startsWith(matrix.os, 'ubuntu')
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 git
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 git
       - name: Build
         if: ${{ !inputs.use_release_artifacts }}
         run: scripts/build.sh ${{ inputs.version && format('--version {0}', inputs.version) || '' }} CC=${{ matrix.cc }} CXX=${{ matrix.cxx }}
@@ -285,7 +285,7 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Install soak dependencies
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y python3 git
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y python3 git
       - name: Download selected portable release container
         uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
@@ -359,7 +359,7 @@ jobs:
       - name: Install deps (Linux)
         if: startsWith(matrix.os, 'ubuntu')
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 git
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 git
       - name: Build (ASan)
         run: |
           SANITIZE="-fsanitize=address,undefined -fno-omit-frame-pointer"

.github/workflows/_test.yml

@@ -170,7 +170,7 @@ jobs:
       - name: Install deps (Ubuntu)
         if: startsWith(matrix.os, 'ubuntu')
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev ccache
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev ccache
 
       # Ubuntu 23.10+ ships kernel.apparmor_restrict_unprivileged_userns=1, which
       # blocks unshare(CLONE_NEWUSER) for unprivileged users. Without this, the
@@ -372,15 +372,15 @@ jobs:
 
       - name: Install deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev ccache
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev ccache
 
       - name: Install LLVM 21 (pinned diagnostic toolchain)
         timeout-minutes: 10
         run: |
           wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
           echo "deb http://apt.llvm.org/noble/ llvm-toolchain-noble-21 main" | sudo tee /etc/apt/sources.list.d/llvm-21.list
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang-21
+          APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update
+          sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang-21
 
       - name: Compiler cache (content-verified, restore)
         uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
@@ -532,7 +532,7 @@ jobs:
       - name: Install deps (Ubuntu)
         if: runner.os == 'Linux'
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang zlib1g-dev ccache
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang zlib1g-dev ccache
 
       - name: Install deps (macOS)
         if: runner.os == 'macOS'

.github/workflows/bug-repro.yml

@@ -56,7 +56,7 @@ jobs:
       - name: Install deps (Ubuntu)
         if: startsWith(matrix.os, 'ubuntu')
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
 
       - name: Run bug-reproduction board
         if: ${{ github.event_name == 'push' || inputs.platforms == 'all' || inputs.platforms == matrix.group }}

.github/workflows/cache-warm.yml

@@ -37,7 +37,7 @@ jobs:
       - name: Install deps (Ubuntu)
         if: startsWith(matrix.os, 'ubuntu')
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev ccache
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev ccache
 
       - name: Install ccache (macOS)
         if: startsWith(matrix.os, 'macos')

.github/workflows/codeql.yml

@@ -96,7 +96,7 @@ jobs:
       - name: Install build dependencies
         if: ${{ matrix.language == 'c-cpp' }}
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
 
       # PR c-cpp: compile the third-party objects (tree-sitter grammars,
       # sqlite, mimalloc, lz4, zstd, the tree-sitter runtime: ~1.3 GB of

.github/workflows/dry-run.yml

@@ -143,7 +143,7 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Install deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev clang llvm libclang-rt-dev
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev clang llvm libclang-rt-dev
       - name: Fuzz smoke (extract, cypher, config)
         run: scripts/fuzz.sh all --runs 20000 --seed 1
       - name: Upload reproducers

.github/workflows/fast-repro.yml

@@ -27,7 +27,7 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Install deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
       - name: test-repro (single platform, ASan; CBM_REPRO_ONLY filters suites)
         env:
           # Optionally narrow to specific suites for a fast targeted check, e.g.

.github/workflows/nightly-soak.yml

@@ -46,7 +46,7 @@ jobs:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       - name: Install deps
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev clang llvm libclang-rt-dev
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev clang llvm libclang-rt-dev
       - name: Fuzz exploration (30 min per target)
         run: scripts/fuzz.sh all --max-total-time 1800 --seed 0
       - name: Upload reproducers

.github/workflows/pr.yml

@@ -69,7 +69,7 @@ jobs:
       - name: Build this checkout's engine
         timeout-minutes: 20
         run: |
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+          APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
           scripts/build.sh CC=gcc CXX=g++
       - name: Select the tests
         id: select
@@ -213,7 +213,7 @@ jobs:
       - name: Install deps (Ubuntu)
         if: matrix.os == 'ubuntu-latest'
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev ccache
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev ccache
 
       - name: Install ccache (macOS)
         if: matrix.os == 'macos-15'
@@ -322,7 +322,7 @@ jobs:
         if: ${{ steps.release.outcome == 'failure' }}
         timeout-minutes: 20
         run: |
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+          APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
           scripts/build.sh CC=gcc CXX=g++
           mkdir -p "$RUNNER_TEMP/cbm-bin"
           cp build/c/codebase-memory-mcp "$RUNNER_TEMP/cbm-bin/"
@@ -334,7 +334,7 @@ jobs:
         if: ${{ steps.release.outcome != 'failure' }}
         timeout-minutes: 20
         run: |
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+          APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
           scripts/build.sh CC=gcc CXX=g++
       - name: Select with the team artifact (engine shadow)
         env:

.github/workflows/smoke.yml

@@ -52,7 +52,7 @@ jobs:
       - name: Install deps (Linux)
         if: startsWith(matrix.os, 'ubuntu')
         timeout-minutes: 10
-        run: sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 git
+        run: APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev python3 git
       - name: Build (production path with explicit test seams)
         run: scripts/build.sh CC=${{ matrix.cc }} CXX=${{ matrix.cxx }} TEST_SEAMS=1
       - name: Smoke invariants

.github/workflows/test-impact-artifact.yml

@@ -46,11 +46,11 @@ jobs:
       - name: Install build deps and LLVM 21 (coverage toolchain)
         timeout-minutes: 10
         run: |
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
+          APT_RETRIES=3; [ -f /etc/apt/apt-mirrors.txt ] && APT_RETRIES=0; sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update && sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y zlib1g-dev
           wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | sudo tee /etc/apt/trusted.gpg.d/apt.llvm.org.asc
           echo "deb http://apt.llvm.org/noble/ llvm-toolchain-noble-21 main" | sudo tee /etc/apt/sources.list.d/llvm-21.list
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update
-          sudo apt-get -o Acquire::Retries=3 -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang-21 llvm-21 libclang-rt-21-dev
+          sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 --error-on=any update
+          sudo apt-get -o Acquire::Retries=$APT_RETRIES -o Acquire::http::Timeout=30 -o Acquire::https::Timeout=30 install -y clang-21 llvm-21 libclang-rt-21-dev
 
       - name: Build the production binary and the coverage runner
         run: |