"Failed to stat include file ...: No such file or directory" with meson projects

[dezgeg]

To reproduce, first pick an example meson project and build it once:

git clone https://github.com/MusicPlayerDaemon/mpc.git
cd mpc
meson setup build
ninja -C build

Now rebuild one file with debug prints on:

SCCACHE_LOG=debug SCCACHE_START_SERVER=1 SCCACHE_NO_DAEMON=1 sccache &
touch src/args.c && ninja -C build

Output:

ninja: Entering directory `build'
[0/2] Compiling C object mpc.p/src_args.c.o[2025-12-05T15:42:36Z DEBUG sccache::server] handle_client: compile
[2025-12-05T15:42:36Z DEBUG sccache::server] check_compiler: Supported compiler
[2025-12-05T15:42:36Z DEBUG sccache::server] parse_arguments: Ok: ["-Impc.p", "-I.", "-I..", "-I../src", "-I../subprojects/libmpdclient/include", "-Isubprojects/libmpdclient", "-I../subprojects/libmpdclient", "-fdiagnostics-color=always", "-D_FILE_OFFSET_BITS=64", "-Wall", "-Winvalid-pch", "-Wextra", "-Wpedantic", "-std=c99", "-O0", "-g", "-D_GNU_SOURCE", "-fvisibility=hidden", "-Wcast-qual", "-Wdouble-promotion", "-Wmissing-declarations", "-Wmissing-prototypes", "-Wshadow", "-Wstrict-prototypes", "-Wunused", "-Wstrict-prototypes", "-Wvla", "-Wwrite-strings", "-Wno-deprecated-declarations", "-MD", "-MQ", "mpc.p/src_args.c.o", "-MF", "mpc.p/src_args.c.o.d", "-o", "mpc.p/src_args.c.o", "-c", "../src/args.c"]
[2025-12-05T15:42:36Z DEBUG sccache::compiler::compiler] [src_args.c.o]: get_cached_or_compile: ["-Impc.p", "-I.", "-I..", "-I../src", "-I../subprojects/libmpdclient/include", "-Isubprojects/libmpdclient", "-I../subprojects/libmpdclient", "-fdiagnostics-color=always", "-D_FILE_OFFSET_BITS=64", "-Wall", "-Winvalid-pch", "-Wextra", "-Wpedantic", "-std=c99", "-O0", "-g", "-D_GNU_SOURCE", "-fvisibility=hidden", "-Wcast-qual", "-Wdouble-promotion", "-Wmissing-declarations", "-Wmissing-prototypes", "-Wshadow", "-Wstrict-prototypes", "-Wunused", "-Wstrict-prototypes", "-Wvla", "-Wwrite-strings", "-Wno-deprecated-declarations", "-MD", "-MQ", "mpc.p/src_args.c.o", "-MF", "mpc.p/src_args.c.o.d", "-o", "mpc.p/src_args.c.o", "-c", "../src/args.c"]
[2025-12-05T15:42:36Z DEBUG sccache::compiler::c] Failed to stat include file /home/dezgeg/mpc/build/src/args.c: No such file or directory (os error 2)
[2025-12-05T15:42:36Z DEBUG sccache::compiler::c] Disabling preprocessor cache mode
[2025-12-05T15:42:36Z DEBUG sccache::compiler::compiler] [src_args.c.o]: generate_hash_key took 0.018 s
[2025-12-05T15:42:36Z DEBUG sccache::compiler::compiler] [src_args.c.o]: Hash key: 5d1237295116f8faba99f272a846d52dd372556d8d637395840d941c0d97c3f8
[2025-12-05T15:42:36Z DEBUG sccache::compiler::compiler] [src_args.c.o]: Cache hit in 0.000 s
[2025-12-05T15:42:36Z DEBUG sccache::server] compile result: cache hit

Problematic line is: Failed to stat include file /home/dezgeg/mpc/build/src/args.c: No such file or directory (os error 2) - it should not have the /build/ subdirectory.

If we look at the preprocessor's output we see that it should be is /home/dezgeg/mpc/build/../src/args.c:

/usr/bin/cc -x c -E -Impc.p -I. -I.. -I../src -I../subprojects/libmpdclient/include -Isubprojects/libmpdclient -I../subprojects/libmpdclient -MD -MF mpc.p/src_args.c.o.d -MQ mpc.p/src_args.c.o -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Wpedantic -std=c99 -O0 -g -D_GNU_SOURCE -fvisibility=hidden -Wcast-qual -Wdouble-promotion -Wmissing-declarations -Wmissing-prototypes -Wshadow -Wstrict-prototypes -Wunused -Wstrict-prototypes -Wvla -Wwrite-strings -Wno-deprecated-declarations ../src/args.c | grep 'args.c'

# 0 "../src/args.c"
# 1 "../src/args.c"
# 5 "../src/args.c" 2

The problematic part of the code seems to be

sccache/src/compiler/c.rs

Line 896 in 9de8d18

let normalized = normalize_path(&path_buf);

- the normalize_path() call for a string like ../src/args.c just throws away the ../ prefix.