Merge #13695: lint: Add linter for circular dependencies

5c613aadd64453c75cb2373c6fcc1326c3cf0b7a lint: Add linter for circular dependencies (Ben Woosley)

Pull request description:

  Protects against added circular depencies, makes it explicit in the
  code when circular dependencies have been removed.

  Modeled after EXPECTED_BOOST_INCLUDES in lint-includes.sh

  Example output:
  ```
  $ test/lint/lint-circular-dependencies.sh
  A new circular dependency in the form of "qt/paymentserver -> qt/walletmodel -> qt/paymentserver" appears to have been introduced.

  $ echo $?
  1
  $ test/lint/lint-circular-dependencies.sh
  Good job! The circular dependency "Fake" is no longer present.
  Please remove it from EXPECTED_CIRCULAR_DEPENDENCIES in test/lint/lint-circular-dependencies.sh
  to make sure this circular dependency is not accidentally reintroduced.

  $ echo $?
  1
  $ test/lint/lint-circular-dependencies.sh
  $ echo $?
  0

  ```

Tree-SHA512: 4519434de29f6d50859daed1480e531c01c1cdbc3f0a5f093251daf62ae2b5b9073fb274b86f541a985e06837aa1165b76558c5f35fb51a759d72e83f1b61e44

1 files changed, 84 insertions, 0 deletions

diff --git a/test/lint/lint-circular-dependencies.sh b/test/lint/lint-circular-dependencies.sh
new file mode 100755
index 0000000000..b8d105b49b
--- /dev/null
+++ b/test/lint/lint-circular-dependencies.sh
@@ -0,0 +1,84 @@
+#!/usr/bin/env bash
+#
+# Copyright (c) 2018 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+#
+# Check for circular dependencies
+
+export LC_ALL=C
+
+EXPECTED_CIRCULAR_DEPENDENCIES=(
+    "chainparamsbase -> util -> chainparamsbase"
+    "checkpoints -> validation -> checkpoints"
+    "index/txindex -> validation -> index/txindex"
+    "policy/fees -> txmempool -> policy/fees"
+    "policy/policy -> validation -> policy/policy"
+    "qt/addresstablemodel -> qt/walletmodel -> qt/addresstablemodel"
+    "qt/bantablemodel -> qt/clientmodel -> qt/bantablemodel"
+    "qt/bitcoingui -> qt/utilitydialog -> qt/bitcoingui"
+    "qt/bitcoingui -> qt/walletframe -> qt/bitcoingui"
+    "qt/bitcoingui -> qt/walletview -> qt/bitcoingui"
+    "qt/clientmodel -> qt/peertablemodel -> qt/clientmodel"
+    "qt/paymentserver -> qt/walletmodel -> qt/paymentserver"
+    "qt/recentrequeststablemodel -> qt/walletmodel -> qt/recentrequeststablemodel"
+    "qt/sendcoinsdialog -> qt/walletmodel -> qt/sendcoinsdialog"
+    "qt/transactiontablemodel -> qt/walletmodel -> qt/transactiontablemodel"
+    "qt/walletmodel -> qt/walletmodeltransaction -> qt/walletmodel"
+    "rpc/rawtransaction -> wallet/rpcwallet -> rpc/rawtransaction"
+    "txmempool -> validation -> txmempool"
+    "validation -> validationinterface -> validation"
+    "wallet/coincontrol -> wallet/wallet -> wallet/coincontrol"
+    "wallet/fees -> wallet/wallet -> wallet/fees"
+    "wallet/rpcwallet -> wallet/wallet -> wallet/rpcwallet"
+    "wallet/wallet -> wallet/walletdb -> wallet/wallet"
+    "policy/fees -> policy/policy -> validation -> policy/fees"
+    "policy/rbf -> txmempool -> validation -> policy/rbf"
+    "qt/addressbookpage -> qt/bitcoingui -> qt/walletview -> qt/addressbookpage"
+    "qt/guiutil -> qt/walletmodel -> qt/optionsmodel -> qt/guiutil"
+    "txmempool -> validation -> validationinterface -> txmempool"
+    "qt/addressbookpage -> qt/bitcoingui -> qt/walletview -> qt/receivecoinsdialog -> qt/addressbookpage"
+    "qt/addressbookpage -> qt/bitcoingui -> qt/walletview -> qt/signverifymessagedialog -> qt/addressbookpage"
+    "qt/guiutil -> qt/walletmodel -> qt/optionsmodel -> qt/intro -> qt/guiutil"
+    "qt/addressbookpage -> qt/bitcoingui -> qt/walletview -> qt/sendcoinsdialog -> qt/sendcoinsentry -> qt/addressbookpage"
+)
+
+EXIT_CODE=0
+
+CIRCULAR_DEPENDENCIES=()
+
+IFS=$'\n'
+for CIRC in $(cd src && ../contrib/devtools/circular-dependencies.py {*,*/*,*/*/*}.{h,cpp} | sed -e 's/^Circular dependency: //'); do
+    CIRCULAR_DEPENDENCIES+=($CIRC)
+    IS_EXPECTED_CIRC=0
+    for EXPECTED_CIRC in "${EXPECTED_CIRCULAR_DEPENDENCIES[@]}"; do
+        if [[ "${CIRC}" == "${EXPECTED_CIRC}" ]]; then
+            IS_EXPECTED_CIRC=1
+            break
+        fi
+    done
+    if [[ ${IS_EXPECTED_CIRC} == 0 ]]; then
+        echo "A new circular dependency in the form of \"${CIRC}\" appears to have been introduced."
+        echo
+        EXIT_CODE=1
+    fi
+done
+
+for EXPECTED_CIRC in "${EXPECTED_CIRCULAR_DEPENDENCIES[@]}"; do
+    IS_PRESENT_EXPECTED_CIRC=0
+    for CIRC in "${CIRCULAR_DEPENDENCIES[@]}"; do
+        if [[ "${CIRC}" == "${EXPECTED_CIRC}" ]]; then
+            IS_PRESENT_EXPECTED_CIRC=1
+            break
+        fi
+    done
+    if [[ ${IS_PRESENT_EXPECTED_CIRC} == 0 ]]; then
+        echo "Good job! The circular dependency \"${EXPECTED_CIRC}\" is no longer present."
+        echo "Please remove it from EXPECTED_CIRCULAR_DEPENDENCIES in $0"
+        echo "to make sure this circular dependency is not accidentally reintroduced."
+        echo
+        EXIT_CODE=1
+    fi
+done
+
+exit ${EXIT_CODE}