Installing psycopg2 fails on MacOS with unclear error message

Question

Trying to install psycopg2 using pip 19.1 on MacOS 10.14.4 returns the lengthy error message below. I understand there are warnings related to gcc, but given the actual error messages I cannot find any clues what the underlying problem is.

I have tried the following actions without any luck:

• Upgraded Xcode to the latest version (10.2.1)
• Upgrade Postgresql to 11.2.1
• Uninstalled psycopg2-binary to prevent any dependency issues
• Cleared all files left by a previously successful install at /Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages (Yes, I had it installed at some point and it worked, not sure why I uninstalled)

There seem to be quite some issues around pip and psycopg2 but no question I found on Stackoverflow showed similar error messages, nor did any of the suggested fixes help. Any pointers to potential fixes are very much appreciated!

pip install psycopg2
Collecting psycopg2
  Using cached https://files.pythonhosted.org/packages/23/7e/93c325482c328619870b6cd09370f6dbe1148283daca65115cd63642e60f/psycopg2-2.8.2.tar.gz
Installing collected packages: psycopg2
  Running setup.py install for psycopg2 ... error
    ERROR: Complete output from command /Library/Frameworks/Python.framework/Versions/3.7/bin/python3.7 -u -c 'import setuptools, tokenize;__file__='"'"'/private/var/folders/y4/3pcgz9d54zj29hfq1lmlxpk80000gn/T/pip-install-ci93cz6u/psycopg2/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /private/var/folders/y4/3pcgz9d54zj29hfq1lmlxpk80000gn/T/pip-record-ztnpuu7u/install-record.txt --single-version-externally-managed --compile:
    ERROR: running install
    running build
    running build_py
    creating build
    creating build/lib.macosx-10.9-x86_64-3.7
    creating build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/_json.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/extras.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/compat.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/errorcodes.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/tz.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/_range.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/_ipaddress.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/_lru_cache.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/__init__.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/extensions.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/errors.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/sql.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    copying lib/pool.py -> build/lib.macosx-10.9-x86_64-3.7/psycopg2
    running build_ext
    building 'psycopg2._psycopg' extension
    creating build/temp.macosx-10.9-x86_64-3.7
    creating build/temp.macosx-10.9-x86_64-3.7/psycopg
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/psycopgmodule.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/psycopgmodule.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/green.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/green.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/pqpath.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/pqpath.o
    psycopg/pqpath.c:135:17: warning: implicit conversion from enumeration type 'ConnStatusType' to different enumeration type 'ExecStatusType' [-Wenum-conversion]
                    PQstatus(conn->pgconn) : PQresultStatus(*pgres)));
                    ^~~~~~~~~~~~~~~~~~~~~~
    psycopg/pqpath.c:1710:11: warning: code will never be executed [-Wunreachable-code]
        ret = 1;
              ^
    psycopg/pqpath.c:1815:17: warning: implicit conversion from enumeration type 'ConnStatusType' to different enumeration type 'ExecStatusType' [-Wenum-conversion]
                    PQstatus(curs->conn->pgconn) : PQresultStatus(curs->pgres)));
                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
    3 warnings generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/utils.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/utils.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/bytes_format.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/bytes_format.o
    In file included from psycopg/bytes_format.c:81:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/libpq_support.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/libpq_support.o
    In file included from psycopg/libpq_support.c:29:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/win32_support.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/win32_support.o
    In file included from psycopg/win32_support.c:27:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/solaris_support.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/solaris_support.o
    In file included from psycopg/solaris_support.c:28:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/connection_int.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/connection_int.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/connection_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/connection_type.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/cursor_int.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/cursor_int.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/cursor_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/cursor_type.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/column_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/column_type.o
    In file included from psycopg/column_type.c:27:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/replication_connection_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/replication_connection_type.o
    In file included from psycopg/replication_connection_type.c:27:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/replication_cursor_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/replication_cursor_type.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/replication_message_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/replication_message_type.o
    In file included from psycopg/replication_message_type.c:27:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/diagnostics_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/diagnostics_type.o
    In file included from psycopg/diagnostics_type.c:27:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/error_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/error_type.o
    In file included from psycopg/error_type.c:27:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/conninfo_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/conninfo_type.o
    In file included from psycopg/conninfo_type.c:27:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/lobject_int.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/lobject_int.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/lobject_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/lobject_type.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/notify_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/notify_type.o
    In file included from psycopg/notify_type.c:27:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/xid_type.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/xid_type.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/adapter_asis.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_asis.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/adapter_binary.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_binary.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/adapter_datetime.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_datetime.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/adapter_list.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_list.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/adapter_pboolean.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pboolean.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/adapter_pdecimal.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pdecimal.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/adapter_pint.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pint.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/adapter_pfloat.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pfloat.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/adapter_qstring.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_qstring.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/microprotocols.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/microprotocols.o
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/microprotocols_proto.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/microprotocols_proto.o
    In file included from psycopg/microprotocols_proto.c:27:
    In file included from ./psycopg/psycopg.h:37:
    ./psycopg/config.h:81:13: warning: unused function 'Dprintf' [-Wunused-function]
    static void Dprintf(const char *fmt, ...) {}
                ^
    1 warning generated.
    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/typecast.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/typecast.o
    gcc -bundle -undefined dynamic_lookup -arch x86_64 -g build/temp.macosx-10.9-x86_64-3.7/psycopg/psycopgmodule.o build/temp.macosx-10.9-x86_64-3.7/psycopg/green.o build/temp.macosx-10.9-x86_64-3.7/psycopg/pqpath.o build/temp.macosx-10.9-x86_64-3.7/psycopg/utils.o build/temp.macosx-10.9-x86_64-3.7/psycopg/bytes_format.o build/temp.macosx-10.9-x86_64-3.7/psycopg/libpq_support.o build/temp.macosx-10.9-x86_64-3.7/psycopg/win32_support.o build/temp.macosx-10.9-x86_64-3.7/psycopg/solaris_support.o build/temp.macosx-10.9-x86_64-3.7/psycopg/connection_int.o build/temp.macosx-10.9-x86_64-3.7/psycopg/connection_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/cursor_int.o build/temp.macosx-10.9-x86_64-3.7/psycopg/cursor_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/column_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/replication_connection_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/replication_cursor_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/replication_message_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/diagnostics_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/error_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/conninfo_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/lobject_int.o build/temp.macosx-10.9-x86_64-3.7/psycopg/lobject_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/notify_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/xid_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_asis.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_binary.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_datetime.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_list.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pboolean.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pdecimal.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pint.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pfloat.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_qstring.o build/temp.macosx-10.9-x86_64-3.7/psycopg/microprotocols.o build/temp.macosx-10.9-x86_64-3.7/psycopg/microprotocols_proto.o build/temp.macosx-10.9-x86_64-3.7/psycopg/typecast.o -L/usr/local/lib -lpq -lssl -lcrypto -o build/lib.macosx-10.9-x86_64-3.7/psycopg2/_psycopg.cpython-37m-darwin.so
    ld: library not found for -lssl
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    error: command 'gcc' failed with exit status 1
    ----------------------------------------
ERROR: Command "/Library/Frameworks/Python.framework/Versions/3.7/bin/python3.7 -u -c 'import setuptools, tokenize;__file__='"'"'/private/var/folders/y4/3pcgz9d54zj29hfq1lmlxpk80000gn/T/pip-install-ci93cz6u/psycopg2/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' install --record /private/var/folders/y4/3pcgz9d54zj29hfq1lmlxpk80000gn/T/pip-record-ztnpuu7u/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /private/var/folders/y4/3pcgz9d54zj29hfq1lmlxpk80000gn/T/pip-install-ci93cz6u/psycopg2/

Answer 1

Thanks for adding the error log, without which it would have been very hard to find the issue. Nice work.

This part of the log was really interesting:

    gcc -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -arch x86_64 -g -DPSYCOPG_VERSION=2.8.2 (dt dec pq3 ext lo64) -DPG_VERSION_NUM=110002 -DHAVE_LO64=1 -I/Library/Frameworks/Python.framework/Versions/3.7/include/python3.7m -I. -I/usr/local/Cellar/postgresql/11.2_1/include -I/usr/local/Cellar/postgresql/11.2_1/include/server -c psycopg/typecast.c -o build/temp.macosx-10.9-x86_64-3.7/psycopg/typecast.o
    gcc -bundle -undefined dynamic_lookup -arch x86_64 -g build/temp.macosx-10.9-x86_64-3.7/psycopg/psycopgmodule.o build/temp.macosx-10.9-x86_64-3.7/psycopg/green.o build/temp.macosx-10.9-x86_64-3.7/psycopg/pqpath.o build/temp.macosx-10.9-x86_64-3.7/psycopg/utils.o build/temp.macosx-10.9-x86_64-3.7/psycopg/bytes_format.o build/temp.macosx-10.9-x86_64-3.7/psycopg/libpq_support.o build/temp.macosx-10.9-x86_64-3.7/psycopg/win32_support.o build/temp.macosx-10.9-x86_64-3.7/psycopg/solaris_support.o build/temp.macosx-10.9-x86_64-3.7/psycopg/connection_int.o build/temp.macosx-10.9-x86_64-3.7/psycopg/connection_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/cursor_int.o build/temp.macosx-10.9-x86_64-3.7/psycopg/cursor_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/column_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/replication_connection_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/replication_cursor_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/replication_message_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/diagnostics_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/error_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/conninfo_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/lobject_int.o build/temp.macosx-10.9-x86_64-3.7/psycopg/lobject_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/notify_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/xid_type.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_asis.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_binary.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_datetime.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_list.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pboolean.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pdecimal.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pint.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_pfloat.o build/temp.macosx-10.9-x86_64-3.7/psycopg/adapter_qstring.o build/temp.macosx-10.9-x86_64-3.7/psycopg/microprotocols.o build/temp.macosx-10.9-x86_64-3.7/psycopg/microprotocols_proto.o build/temp.macosx-10.9-x86_64-3.7/psycopg/typecast.o -L/usr/local/lib -lpq -lssl -lcrypto -o build/lib.macosx-10.9-x86_64-3.7/psycopg2/_psycopg.cpython-37m-darwin.so
    ld: library not found for -lssl

The 2nd gcc had a mention of this:

-L/usr/local/lib -lpq -lssl -lcrypto -o ...

That means, compilation process was looking for a library (-l) that happens to be ssl. See gcc manual (https://linux.die.net/man/1/gcc). It says that -l is to search the library named library (in our case ssl) when linking.

Something with ssl library was missing.

Google search lead to a reported issue: https://github.com/psycopg/psycopg2/issues/492. Joe Kemp's answer (https://github.com/psycopg/psycopg2/issues/492#issuecomment-278481164) suggests setting an environment variable like so:

export LDFLAGS="-L/usr/local/opt/openssl/lib"

Other options were listed here: Can't install psycopg2 with pip in virtualenv on Mac OS X 10.7.

It appears that your setting LDFLAGS solved the issue.

Answer 2

I had this problem running pip install psycopg2 while I was running OSX 10.14.4. I fixed it by:

1. Running pg_config and noticed the variable:

   CPPFLAGS = -I/usr/local/Cellar/icu4c/63.1/include -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk -I/usr/local/opt/openssl/include -I/usr/local/opt/readline/include -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/usr/include/libxml2
   

   However /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk did not exist on my machine.

   So I changed it to /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk

2. I ran these two commands:

   export CPPFLAGS="-I/usr/local/Cellar/icu4c/63.1/include -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.sdk -I/usr/local/opt/openssl/include -I/usr/local/opt/readline/include -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.14.sdk/usr/include/libxml2"
   
   pip install psycopg2