Different results betweent "compiledb make" and "make | compiledb"

[J-keaper]

I have these following files.

➜  test-compiledb$ tree                        
.
├── Makefile 
├── main.c
└── subdir
    ├── Makefile
    └── main.c

➜  test-compiledb$ cat Makefile 
default:
	make -w -C subdir
	gcc main.c -o main.o
clean:
	rm -rf subdir/main.o main.o
➜  test-compiledb$ cat subdir/Makefile
default:
	gcc main.c -o main.o 

I found the different results between compiledb make and make | compiledb.

➜  test-compiledb$ compiledb make           
## Building [make]...
make -w -C subdir
make[1]: Entering directory `/Users/jiajiawang/Workspace/test-compiledb/subdir'
gcc main.c -o main.o
make[1]: Leaving directory `/Users/jiajiawang/Workspace/test-compiledb/subdir'
gcc main.c -o main.o

➜  test-compiledb$ cat compile_commands.json 
[
 {
  "directory": "/Users/jiajiawang/Workspace/test-compiledb",
  "arguments": [
   "gcc",
   "main.c",
   "-o",
   "main.o"
  ],
  "file": "main.c"
 }
]

One entry correspond to main.c in subdir is missing.
It's confusing that if you use make | compiledb, everything is ok.

➜  test-compiledb$ make | compiledb            
➜  test-compiledb$ cat compile_commands.json   
[
 {
  "directory": "/Users/jiajiawang/Workspace/test-compiledb/subdir",
  "arguments": [
   "gcc",
   "main.c",
   "-o",
   "main.o"
  ],
  "file": "main.c"
 },
 {
  "directory": "/Users/jiajiawang/Workspace/test-compiledb",
  "arguments": [
   "gcc",
   "main.c",
   "-o",
   "main.o"
  ],
  "file": "main.c"
 }
]

Can someone tell me why？

[J-keaper]

Add more detail message.

Verbose message for compiledb make:

➜  test-compiledb$ compiledb -v make
## Building [make]...
make -w -C subdir
make[1]: Entering directory `/Users/jiajiawang/Workspace/test-compiledb/subdir'
gcc main.c -o main.o
make[1]: Leaving directory `/Users/jiajiawang/Workspace/test-compiledb/subdir'
gcc main.c -o main.o

## Processing build commands from <stdout>
Line 1: Failed to parse build command [Details: (<class 'bashlex.tokenizer.MatchedPairError'>) unexpected EOF while looking for matching '`' (position 69)]. Ignoring: 'make: Entering directory `/Users/jiajiawang/Workspace/test-compiledb''
New command: make -w -C subdir
New command: gcc main.c -o main.o
Adding command 0: gcc main.c -o main.o
Line 4: Failed to parse build command [Details: (<class 'bashlex.tokenizer.MatchedPairError'>) unexpected EOF while looking for matching '`' (position 68)]. Ignoring: 'make: Leaving directory `/Users/jiajiawang/Workspace/test-compiledb''
## Failed to read previous compile_commands.json: Expecting value: line 1 column 1 (char 0)
## Writing compilation database with 1 entries to compile_commands.json
## Done.

Verbose message for make | compiledb:

➜  test-compiledb$ make | compiledb -v
## Processing build commands from <stdin>
New command: make -w -C subdir
New command: gcc main.c -o main.o
Adding command 0: gcc main.c -o main.o
New command: gcc main.c -o main.o
Adding command 1: gcc main.c -o main.o
## Loaded compilation database with 2 entries from compile_commands.json
## Writing compilation database with 2 entries to compile_commands.json
## Done.

Hope this is helpful.